draft-ietf-mpls-cr-ldp-06.txt   rfc3212.txt 
MPLS Working Group Bilel Jamoussi, Editor Network Working Group B. Jamoussi, Editor, Nortel Networks
Internet Draft Nortel Networks Corp. Request for Comments: 3212 L. Andersson, Utfors AB
Expiration Date: May 2002 Category: Standards Track R. Callon, Juniper Networks
R. Dantu, Netrake Corporation
O. Aboul-Magd, P. Ashwood-Smith, L. Wu, Cisco Systems
F. Hellstrand, K. Sundell, Nortel Networks Corp. P. Doolan, OTB Consulting Corp.
L. Andersson, Utfors T. Worster
R. Callon, Juniper Networks. N. Feldman, IBM Corp.
R. Dantu, L. Wu, Cisco Systems A. Fredette, ANF Consulting
P. Doolan, T. Worster, Ennovate Networks Corp. M. Girish, Atoga Systems
N. Feldman, IBM Corp. E. Gray, Sandburst
A. Fredette, PhotonEx Corp. J. Heinanen, Song Networks, Inc.
M. Girish, Atoga Systems T. Kilty, Newbridge Networks, Inc.
E. Gray, Sandburst A. Malis, Vivace Networks
J. Halpern, Longitude Systems, Inc. January 2002
J. Heinanen, Telia Finland
T. Kilty, Newbridge Networks, Inc.
A. Malis, Vivace Networks
P. Vaananen, Nokia Telecommunications
November 2001
Constraint-Based LSP Setup using LDP
draft-ietf-mpls-cr-ldp-06.txt Constraint-Based LSP Setup using LDP
Status of this Memo Status of this Memo
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Abstract Abstract
Label Distribution Protocol (LDP) is defined in [1] for distribution This document specifies mechanisms and TLVs (Type/Length/Value) for
of labels inside one MPLS domain. One of the most important support of CR-LSPs (constraint-based routed Label Switched Path)
services that may be offered using MPLS in general and LDP in using LDP (Label Distribution Protocol).
particular is support for constraint-based routing of traffic across
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 1
the routed network. Constraint-based routing offers the opportunity
to extend the information used to setup paths beyond what is
available for the routing protocol. For instance, an LSP can be
setup based on explicit route constraints, QoS constraints, and
other constraints. Constraint-based routing (CR) is a mechanism used
to meet Traffic Engineering requirements that have been proposed by,
[2] and [3]. These requirements may be met by extending LDP for
support of constraint-based routed label switched paths (CR-LSPs).
Other uses for CR-LSPs include MPLS-based VPNs [4]. More information
about the applicability of CR-LDP can be found in [5].
This draft specifies mechanisms and TLVs for support of CR-LSPs This specification proposes an end-to-end setup mechanism of a CR-LSP
initiated by the ingress LSR (Label Switching Router). We also
specify mechanisms to provide means for reservation of resources
using LDP. using LDP.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
in this document are to be interpreted as described in RFC 2119 [6]. document are to be interpreted as described in RFC 2119 [6].
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 2 Table of Contents
Table of Contents
1. Introduction....................................................4 1. Introduction....................................................3
2. Constraint-based Routing Overview...............................4 2. Constraint-based Routing Overview...............................4
2.1 Strict and Loose Explicit Routes...............................5 2.1 Strict and Loose Explicit Routes...............................5
2.2 Traffic Characteristics........................................5 2.2 Traffic Characteristics........................................5
2.3 Pre-emption....................................................6 2.3 Preemption.....................................................5
2.4 Route Pinning..................................................6 2.4 Route Pinning..................................................6
2.5 Resource Class.................................................6 2.5 Resource Class.................................................6
3. Solution Overview...............................................6 3. Solution Overview...............................................6
3.1 Required Messages and TLVs.....................................8 3.1 Required Messages and TLVs.....................................7
3.2 Label Request Message..........................................8 3.2 Label Request Message..........................................7
3.3 Label Mapping Message..........................................9 3.3 Label Mapping Message..........................................9
3.4 Notification Message...........................................9 3.4 Notification Message..........................................10
3.5 Release , Withdraw, and Abort Messages........................10 3.5 Release , Withdraw, and Abort Messages........................11
4. Protocol Specification.........................................10 4. Protocol Specification.........................................11
4.1 Explicit Route TLV (ER-TLV)...................................11 4.1 Explicit Route TLV (ER-TLV)...................................11
4.2 Explicit Route Hop TLV (ER-Hop TLV)...........................11 4.2 Explicit Route Hop TLV (ER-Hop TLV)...........................12
4.3 Traffic Parameters TLV........................................12 4.3 Traffic Parameters TLV........................................13
4.3.1 Semantics...................................................14 4.3.1 Semantics...................................................15
4.3.1.1 Frequency.................................................14 4.3.1.1 Frequency.................................................15
4.3.1.2 Peak Rate.................................................14 4.3.1.2 Peak Rate.................................................16
4.3.1.3 Committed Rate............................................14 4.3.1.3 Committed Rate............................................16
4.3.1.4 Excess Burst Size.........................................15 4.3.1.4 Excess Burst Size.........................................16
4.3.1.5 Peak Rate Token Bucket....................................15 4.3.1.5 Peak Rate Token Bucket....................................16
4.3.1.6 Committed Data Rate Token Bucket..........................15 4.3.1.6 Committed Data Rate Token Bucket..........................17
4.3.1.7 Weight....................................................16 4.3.1.7 Weight....................................................18
4.3.2 Procedures..................................................16 4.3.2 Procedures..................................................18
4.3.2.1 Label Request Message.....................................16 4.3.2.1 Label Request Message.....................................18
4.3.2.2 Label Mapping Message.....................................17 4.3.2.2 Label Mapping Message.....................................18
4.3.2.3 Notification Message......................................17 4.3.2.3 Notification Message......................................19
4.4 Preemption TLV................................................17 4.4 Preemption TLV................................................19
4.5 LSPID TLV.....................................................18 4.5 LSPID TLV.....................................................20
4.6 Resource Class (Color) TLV....................................20 4.6 Resource Class (Color) TLV....................................21
4.7 ER-Hop semantics..............................................20 4.7 ER-Hop semantics..............................................22
4.7.1. ER-Hop 1: The IPv4 prefix..................................20 4.7.1. ER-Hop 1: The IPv4 prefix..................................22
4.7.2. ER-Hop 2: The IPv6 address.................................21 4.7.2. ER-Hop 2: The IPv6 address.................................23
4.7.3. ER-Hop 3: The autonomous system number....................21 4.7.3. ER-Hop 3: The autonomous system number....................24
4.7.4. ER-Hop 4: LSPID............................................22 4.7.4. ER-Hop 4: LSPID............................................24
4.8. Processing of the Explicit Route TLV.........................23 4.8. Processing of the Explicit Route TLV.........................26
4.8.1. Selection of the next hop..................................23 4.8.1. Selection of the next hop..................................26
4.8.2. Adding ER-Hops to the explicit route TLV...................25 4.8.2. Adding ER-Hops to the explicit route TLV...................27
4.9 Route Pinning TLV.............................................25 4.9 Route Pinning TLV.............................................28
4.10 CR-LSP FEC Element...........................................26 4.10 CR-LSP FEC Element...........................................28
5. IANA Considerations............................................26 5. IANA Considerations............................................29
5.1 TLV Type Name Space...........................................26 5.1 TLV Type Name Space...........................................29
5.2 FEC Type Name Space...........................................27 5.2 FEC Type Name Space...........................................30
5.3 Status Code Space.............................................27 5.3 Status Code Space.............................................30
6. Security.......................................................28 6. Security Considerations........................................31
7. Acknowledgments................................................28 7. Acknowledgments................................................31
8. Intellectual Property Consideration............................28 8. Intellectual Property Consideration............................31
9. References.....................................................32
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 3 Appendix A: CR-LSP Establishment Examples.........................33
9. References.....................................................28 A.1 Strict Explicit Route Example.................................33
10. Author's Addresses............................................29 A.2 Node Groups and Specific Nodes Example........................34
Appendix A: CR-LSP Establishment Examples.........................31 Appendix B. QoS Service Examples..................................36
A.1 Strict Explicit Route Example.................................31 B.1 Service Examples..............................................36
A.2 Node Groups and Specific Nodes Example........................32 B.2 Establishing CR-LSP Supporting Real-Time Applications.........38
Appendix B. QoS Service Examples..................................35 B.3 Establishing CR-LSP Supporting Delay Insensitive Applications.38
B.1 Service Examples..............................................35 Author's Addresses................................................39
B.2 Establishing CR-LSP Supporting Real-Time Applications.........36 Full Copyright Statement..........................................42
B.3 Establishing CR-LSP Supporting Delay Insensitive Applications.37
1. Introduction 1. Introduction
Label Distribution Protocol (LDP) is defined in [1] for distribution
of labels inside one MPLS domain. One of the most important services
that may be offered using MPLS in general and LDP in particular is
support for constraint-based routing of traffic across the routed
network. Constraint-based routing offers the opportunity to extend
the information used to setup paths beyond what is available for the
routing protocol. For instance, an LSP can be setup based on
explicit route constraints, QoS constraints, and other constraints.
Constraint-based routing (CR) is a mechanism used to meet Traffic
Engineering requirements that have been proposed by, [2] and [3].
These requirements may be met by extending LDP for support of
constraint-based routed label switched paths (CR-LSPs). Other uses
for CR-LSPs include MPLS-based VPNs [4]. More information about the
applicability of CR-LDP can be found in [5].
The need for constraint-based routing (CR) in MPLS has been explored The need for constraint-based routing (CR) in MPLS has been explored
elsewhere [2], and [3]. Explicit routing is a subset of the more elsewhere [2], and [3]. Explicit routing is a subset of the more
general constraint-based routing function. At the MPLS WG meeting general constraint-based routing function. At the MPLS WG meeting
held during the Washington IETF (December 1997) there was consensus held during the Washington IETF (December 1997) there was consensus
that LDP should support explicit routing of LSPs with provision for that LDP should support explicit routing of LSPs with provision for
indication of associated (forwarding) priority. In the Chicago indication of associated (forwarding) priority. In the Chicago
meeting (August 1998), a decision was made that support for explicit meeting (August 1998), a decision was made that support for explicit
path setup in LDP will be moved to a separate document. This path setup in LDP will be moved to a separate document. This
document provides that support and it has been accepted as a working document provides that support and it has been accepted as a working
document in the Orlando meeting (December 1998). document in the Orlando meeting (December 1998).
This specification proposes an end-to-end setup mechanism of a This specification proposes an end-to-end setup mechanism of a
constraint-based routed LSP (CR-LSP) initiated by the ingress LSR. constraint-based routed LSP (CR-LSP) initiated by the ingress LSR. We
We also specify mechanisms to provide means for reservation of also specify mechanisms to provide means for reservation of resources
resources using LDP. using LDP.
This document introduce TLVs and procedures that provide support This document introduce TLVs and procedures that provide support for:
for:
- Strict and Loose Explicit Routing - Strict and Loose Explicit Routing
- Specification of Traffic Parameters - Specification of Traffic Parameters
- Route Pinning - Route Pinning
- CR-LSP Pre-emption though setup/holding priorities - CR-LSP Preemption though setup/holding priorities
- Handling Failures - Handling Failures
- LSPID - LSPID
- Resource Class - Resource Class
Section 2 introduces the various constraints defined in this Section 2 introduces the various constraints defined in this
specification. Section 3 outlines the CR-LDP solution. Section 4 specification. Section 3 outlines the CR-LDP solution. Section 4
defines the TLVs and procedures used to setup constraint-based defines the TLVs and procedures used to setup constraint-based routed
routed label switched paths. Appendix A provides several examples label switched paths. Appendix A provides several examples of CR-LSP
of CR-LSP path setup. Appendix B provides Service Definition path setup. Appendix B provides Service Definition Examples.
Examples.
2. Constraint-based Routing Overview 2. Constraint-based Routing Overview
Constraint-based routing is a mechanism that supports the Traffic Constraint-based routing is a mechanism that supports the Traffic
Engineering requirements defined in [3]. Explicit Routing is a Engineering requirements defined in [3]. Explicit Routing is a
subset of the more general constraint-based routing where the subset of the more general constraint-based routing where the
constraint is the explicit route (ER). Other constraints are defined constraint is the explicit route (ER). Other constraints are defined
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 4
to provide a network operator with control over the path taken by an to provide a network operator with control over the path taken by an
LSP. This section is an overview of the various constraints LSP. This section is an overview of the various constraints
supported by this specification. supported by this specification.
Like any other LSP a CR-LSP is a path through an MPLS network. The Like any other LSP a CR-LSP is a path through an MPLS network. The
difference is that while other paths are setup solely based on difference is that while other paths are setup solely based on
information in routing tables or from a management system, the information in routing tables or from a management system, the
constraint-based route is calculated at one point at the edge of constraint-based route is calculated at one point at the edge of
network based on criteria, including but not limited to routing network based on criteria, including but not limited to routing
information. The intention is that this functionality shall give information. The intention is that this functionality shall give
desired special characteristics to the LSP in order to better desired special characteristics to the LSP in order to better support
support the traffic sent over the LSP. The reason for setting up CR- the traffic sent over the LSP. The reason for setting up CR-LSPs
LSPs might be that one wants to assign certain bandwidth or other might be that one wants to assign certain bandwidth or other Service
Service Class characteristics to the LSP, or that one wants to make Class characteristics to the LSP, or that one wants to make sure that
sure that alternative routes use physically separate paths through alternative routes use physically separate paths through the network.
the network.
2.1 Strict and Loose Explicit Routes 2.1 Strict and Loose Explicit Routes
An explicit route is represented in a Label Request Message as a An explicit route is represented in a Label Request Message as a list
list of nodes or groups of nodes along the constraint-based route. of nodes or groups of nodes along the constraint-based route. When
When the CR-LSP is established, all or a subset of the nodes in a the CR-LSP is established, all or a subset of the nodes in a group
group may be traversed by the LSP. Certain operations to be may be traversed by the LSP. Certain operations to be performed
performed along the path can also be encoded in the constraint-based along the path can also be encoded in the constraint-based route.
route.
The capability to specify, in addition to specified nodes, groups of The capability to specify, in addition to specified nodes, groups of
nodes, of which a subset will be traversed by the CR-LSP, allows the nodes, of which a subset will be traversed by the CR-LSP, allows the
system a significant amount of local flexibility in fulfilling a system a significant amount of local flexibility in fulfilling a
request for a constraint-based route. This allows the generator of request for a constraint-based route. This allows the generator of
the constraint-based route to have some degree of imperfect the constraint-based route to have some degree of imperfect
information about the details of the path. information about the details of the path.
The constraint-based route is encoded as a series of ER-Hops The constraint-based route is encoded as a series of ER-Hops
contained in a constraint-based route TLV. Each ER-Hop may identify contained in a constraint-based route TLV. Each ER-Hop may identify
a group of nodes in the constraint-based route. A constraint-based a group of nodes in the constraint-based route. A constraint-based
route is then a path including all of the identified groups of nodes route is then a path including all of the identified groups of nodes
in the order in which they appear in the TLV. in the order in which they appear in the TLV.
To simplify the discussion, we call each group of nodes an abstract To simplify the discussion, we call each group of nodes an "abstract
node. Thus, we can also say that a constraint-based route is a path node". Thus, we can also say that a constraint-based route is a path
including all of the abstract nodes, with the specified operations including all of the abstract nodes, with the specified operations
occurring along that path. occurring along that path.
2.2 Traffic Characteristics 2.2 Traffic Characteristics
The traffic characteristics of a path are described in the Traffic The traffic characteristics of a path are described in the Traffic
Parameters TLV in terms of a peak rate, committed rate, and service Parameters TLV in terms of a peak rate, committed rate, and service
granularity. The peak and committed rates describe the bandwidth granularity. The peak and committed rates describe the bandwidth
constraints of a path while the service granularity can be used to constraints of a path while the service granularity can be used to
specify a constraint on the delay variation that the CR-LDP MPLS specify a constraint on the delay variation that the CR-LDP MPLS
domain may introduce to a path's traffic. domain may introduce to a path's traffic.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 5 2.3 Preemption
2.3 Pre-emption
CR-LDP signals the resources required by a path on each hop of the CR-LDP signals the resources required by a path on each hop of the
route. If a route with sufficient resources can not be found, route. If a route with sufficient resources can not be found,
existing paths may be rerouted to reallocate resources to the new existing paths may be rerouted to reallocate resources to the new
path. This is the process of path pre-emption. Setup and holding path. This is the process of path preemption. Setup and holding
priorities are used to rank existing paths (holding priority) and priorities are used to rank existing paths (holding priority) and the
the new path (setup priority) to determine if the new path can pre- new path (setup priority) to determine if the new path can preempt an
empt an existing path. existing path.
The setupPriority of a new CR-LSP and the holdingPriority attributes The setupPriority of a new CR-LSP and the holdingPriority attributes
of the existing CR-LSP are used to specify priorities. Signaling a of the existing CR-LSP are used to specify priorities. Signaling a
higher holding priority express that the path, once it has been higher holding priority express that the path, once it has been
established, should have a lower chance of being pre-empted. established, should have a lower chance of being preempted. Signaling
Signaling a higher setup priority expresses the expectation that, in a higher setup priority expresses the expectation that, in the case
the case that resource are unavailable, the path is more likely to that resource are unavailable, the path is more likely to preempt
pre-empt other paths. The exact rules determining bumping are an other paths. The exact rules determining bumping are an aspect of
aspect of network policy. network policy.
The allocation of setup and holding priority values to paths is an The allocation of setup and holding priority values to paths is an
aspect of network policy. aspect of network policy.
The setup and holding priority values range from zero (0) to seven The setup and holding priority values range from zero (0) to seven
(7). The value zero (0) is the priority assigned to the most (7). The value zero (0) is the priority assigned to the most
important path. It is referred to as the highest priority. Seven (7) important path. It is referred to as the highest priority. Seven
is the priority for the least important path. The use of default (7) is the priority for the least important path. The use of default
priority values is an aspect of network policy. The recommended priority values is an aspect of network policy. The recommended
default value is (4). default value is (4).
The setupPriority of a CR-LSP should not be higher (numerically The setupPriority of a CR-LSP should not be higher (numerically less)
less) than its holdingPriority since it might bump an LSP and be than its holdingPriority since it might bump an LSP and be bumped by
bumped by the next "equivalent" request. the next "equivalent" request.
2.4 Route Pinning 2.4 Route Pinning
Route pinning is applicable to segments of an LSP that are loosely Route pinning is applicable to segments of an LSP that are loosely
routed - i.e. those segments which are specified with a next hop routed - i.e. those segments which are specified with a next hop with
with the "L" bit set or where the next hop is an "abstract node". A the "L" bit set or where the next hop is an abstract node. A CR-LSP
CR-LSP may be setup using route pinning if it is undesirable to may be setup using route pinning if it is undesirable to change the
change the path used by an LSP even when a better next hop becomes path used by an LSP even when a better next hop becomes available at
available at some LSR along the loosely routed portion of the LSP. some LSR along the loosely routed portion of the LSP.
2.5 Resource Class 2.5 Resource Class
The network operator may classify network resources in various ways. The network operator may classify network resources in various ways.
These classes are also known as "colors" or "administrative groups". These classes are also known as "colors" or "administrative groups".
When a CR-LSP is being established, it's necessary to indicate which When a CR-LSP is being established, it's necessary to indicate which
resource classes the CR-LSP can draw from. resource classes the CR-LSP can draw from.
3. Solution Overview 3. Solution Overview
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 6
CR-LSP over LDP Specification is designed with the following goals: CR-LSP over LDP Specification is designed with the following goals:
1. Meet the requirements outlined in [3] for performing traffic 1. Meet the requirements outlined in [3] for performing traffic
engineering and provide a solid foundation for performing more engineering and provide a solid foundation for performing more
general constraint-based routing. general constraint-based routing.
2. Build on already specified functionality that meets the 2. Build on already specified functionality that meets the
requirements whenever possible. Hence, this specification is requirements whenever possible. Hence, this specification is
based on [1]. based on [1].
3. Keep the solution simple. 3. Keep the solution simple.
In this document, support for unidirectional point-to-point CR-LSPs In this document, support for unidirectional point-to-point CR-LSPs
is specified. Support for point-to-multipoint, multipoint-to-point, is specified. Support for point-to-multipoint, multipoint-to-point,
is for further study (FFS). is for further study (FFS).
Support for constraint-based routed LSPs in this specification Support for constraint-based routed LSPs in this specification
depends on the following minimal LDP behaviors as specified in [1]: depends on the following minimal LDP behaviors as specified in [1]:
- Use of Basic and/or Extended Discovery Mechanisms. - Use of Basic and/or Extended Discovery Mechanisms.
- Use of the Label Request Message defined in [1] in downstream on - Use of the Label Request Message defined in [1] in downstream
demand label advertisement mode with ordered control. on demand label advertisement mode with ordered control.
- Use of the Label Mapping Message defined in [1] in downstream on - Use of the Label Mapping Message defined in [1] in downstream
demand mode with ordered control. on demand mode with ordered control.
- Use of the Notification Message defined in [1]. - Use of the Notification Message defined in [1].
- Use of the Withdraw and Release Messages defined in [1]. - Use of the Withdraw and Release Messages defined in [1].
- Use of the Loop Detection (in the case of loosely routed - Use of the Loop Detection (in the case of loosely routed
segments of a CR-LSP) mechanisms defined in [1]. segments of a CR-LSP) mechanisms defined in [1].
In addition, the following functionality is added to what's defined In addition, the following functionality is added to what's defined
in [1]: in [1]:
- The Label Request Message used to setup a CR-LSP includes one or - The Label Request Message used to setup a CR-LSP includes one
more CR-TLVs defined in Section 4. For instance, the Label Request or more CR-TLVs defined in Section 4. For instance, the Label
Message may include the ER-TLV. Request Message may include the ER-TLV.
- An LSR implicitly infers ordered control from the existence of - An LSR implicitly infers ordered control from the existence of
one or more CR-TLVs in the Label Request Message. This means that one or more CR-TLVs in the Label Request Message. This means
the LSR can still be configured for independent control for LSPs that the LSR can still be configured for independent control
established as a result of dynamic routing. However, when a Label for LSPs established as a result of dynamic routing. However,
Request Message includes one or more of the CR-TLVs, then ordered when a Label Request Message includes one or more of the CR-
control is used to setup the CR-LSP. Note that this is also true TLVs, then ordered control is used to setup the CR-LSP. Note
for the loosely routed parts of a CR-LSP. that this is also true for the loosely routed parts of a CR-
LSP.
- New status codes are defined to handle error notification for - New status codes are defined to handle error notification for
failure of established paths specified in the CR-TLVs. All of the failure of established paths specified in the CR-TLVs. All of
new status codes require that the F bit be set. the new status codes require that the F bit be set.
Optional TLVs MUST be implemented to be compliant with the protocol. Optional TLVs MUST be implemented to be compliant with the protocol.
However, they are optionally carried in the CR-LDP messages to However, they are optionally carried in the CR-LDP messages to signal
signal certain characteristics of the CR-LSP being established or certain characteristics of the CR-LSP being established or modified.
modified.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 7
Examples of CR-LSP establishment are given in Appendix A to Examples of CR-LSP establishment are given in Appendix A to
illustrate how the mechanisms described in this draft work. illustrate how the mechanisms described in this document work.
3.1 Required Messages and TLVs 3.1 Required Messages and TLVs
Any Messages, TLVs, and procedures not defined explicitly in this Any Messages, TLVs, and procedures not defined explicitly in this
document are defined in the LDP Specification [1]. The reader can document are defined in the LDP Specification [1]. The reader can
use [7] as an informational document about the state transitions, use [7] as an informational document about the state transitions,
which relate to CR-LDP messages. which relate to CR-LDP messages.
The following subsections are meant as a cross-reference to the [1] The following subsections are meant as a cross-reference to the [1]
document and indication of additional functionality beyond what's document and indication of additional functionality beyond what's
defined in [1] where necessary. defined in [1] where necessary.
Note that use of the Status TLV is not limited to Notification Note that use of the Status TLV is not limited to Notification
messages as specified in Section 3.4.6 of [1]. A message other than messages as specified in Section 3.4.6 of [1]. A message other than
a Notification message may carry a Status TLV as an Optional a Notification message may carry a Status TLV as an Optional
Parameter. When a message other than a Notification carries a Parameter. When a message other than a Notification carries a Status
Status TLV the U-bit of the Status TLV should be set to 1 to TLV the U-bit of the Status TLV should be set to 1 to indicate that
indicate that the receiver should silently discard the TLV if the receiver should silently discard the TLV if unprepared to handle
unprepared to handle it. it.
3.2 Label Request Message 3.2 Label Request Message
The Label Request Message is as defined in 3.5.8 of [1] with the The Label Request Message is as defined in 3.5.8 of [1] with the
following modifications (required only if any of the CR-TLVs is following modifications (required only if any of the CR-TLVs is
included in the Label Request Message): included in the Label Request Message):
- The Label Request Message MUST include a single FEC-TLV element. - The Label Request Message MUST include a single FEC-TLV
The CR-LSP FEC TLV element SHOULD be used. However, the other FEC- element. The CR-LSP FEC TLV element SHOULD be used. However,
TLVs defined in [1] MAY be used instead for certain applications. the other FEC- TLVs defined in [1] MAY be used instead for
certain applications.
- The Optional Parameters TLV includes the definition of any of - The Optional Parameters TLV includes the definition of any of
the Constraint-based TLVs specified in Section 4. the Constraint-based TLVs specified in Section 4.
- The Procedures to handle the Label Request Message are augmented - The Procedures to handle the Label Request Message are
by the procedures for processing of the CR-TLVs as defined in augmented by the procedures for processing of the CR-TLVs as
Section 4. defined in Section 4.
The encoding for the CR-LDP Label Request Message is as follows: The encoding for the CR-LDP Label Request Message is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| Label Request (0x0401) | Message Length | |0| Label Request (0x0401) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID | | Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC TLV | | FEC TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSPID TLV (CR-LDP, mandatory) | | LSPID TLV (CR-LDP, mandatory) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 8
| ER-TLV (CR-LDP, optional) | | ER-TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic TLV (CR-LDP, optional) | | Traffic TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Pinning TLV (CR-LDP, optional) | | Pinning TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Resource Class TLV (CR-LDP, optional) | | Resource Class TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Pre-emption TLV (CR-LDP, optional) | | Preemption TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.3 Label Mapping Message 3.3 Label Mapping Message
The Label Mapping Message is as defined in 3.5.7 of [1] with the The Label Mapping Message is as defined in 3.5.7 of [1] with the
following modifications: following modifications:
- The Label Mapping Message MUST include a single Label-TLV. - The Label Mapping Message MUST include a single Label-TLV.
- The Label Mapping Message Procedures are limited to downstream - The Label Mapping Message Procedures are limited to downstream
on demand ordered control mode. on demand ordered control mode.
A Mapping message is transmitted by a downstream LSR to an upstream A Mapping message is transmitted by a downstream LSR to an upstream
LSR under one of the following conditions: LSR under one of the following conditions:
1. The LSR is the egress end of the CR-LSP and an upstream 1. The LSR is the egress end of the CR-LSP and an upstream mapping
mapping has been requested. has been requested.
2. The LSR received a mapping from its downstream next hop LSR 2. The LSR received a mapping from its downstream next hop LSR for
for an CR-LSP for which an upstream request is still pending. an CR-LSP for which an upstream request is still pending.
The encoding for the CR-LDP Label Mapping Message is as follows: The encoding for the CR-LDP Label Mapping Message is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| Label Mapping (0x0400) | Message Length | |0| Label Mapping (0x0400) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID | | Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at line 448 skipping to change at page 10, line 27
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label Request Message ID TLV | | Label Request Message ID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSPID TLV (CR-LDP, optional) | | LSPID TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic TLV (CR-LDP, optional) | | Traffic TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.4 Notification Message 3.4 Notification Message
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 9
The Notification Message is as defined in Section 3.5.1 of [1] and The Notification Message is as defined in Section 3.5.1 of [1] and
the Status TLV encoding is as defined in Section 3.4.6 of [1]. the Status TLV encoding is as defined in Section 3.4.6 of [1].
Establishment of an CR-LSP may fail for a variety of reasons. All Establishment of an CR-LSP may fail for a variety of reasons. All
such failures are considered advisory conditions and they are such failures are considered advisory conditions and they are
signaled by the Notification Message. signaled by the Notification Message.
Notification Messages carry Status TLVs to specify events being Notification Messages carry Status TLVs to specify events being
signaled. New status codes are defined in Section 4.11 to signal signaled. New status codes are defined in Section 4.11 to signal
error notifications associated with the establishment of a CR-LSP error notifications associated with the establishment of a CR-LSP and
and the processing of the CR-TLV. All of the new status codes the processing of the CR-TLV. All of the new status codes require
require that the F bit be set. that the F bit be set.
The Notification Message MAY carry the LSPID TLV of the The Notification Message MAY carry the LSPID TLV of the corresponding
corresponding CR-LSP. CR-LSP.
Notification Messages MUST be forwarded toward the LSR originating Notification Messages MUST be forwarded toward the LSR originating
the Label Request at each hop and at any time that procedures in the Label Request at each hop and at any time that procedures in this
this specification - or in [1] - specify sending of a Notification specification - or in [1] - specify sending of a Notification Message
Message in response to a Label Request Message. in response to a Label Request Message.
The encoding of the notification message is as follows: The encoding of the notification message is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| Notification (0x0001) | Message Length | |0| Notification (0x0001) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID | | Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status (TLV) | | Status (TLV) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Optional Parameters | | Optional Parameters |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.5 Release , Withdraw, and Abort Messages 3.5 Release , Withdraw, and Abort Messages
The Label Release , Label Withdraw, and Label Abort Request Messages The Label Release , Label Withdraw, and Label Abort Request Messages
are used as specified in [1]. These messages may also carry the are used as specified in [1]. These messages MAY also carry the
LSPID TLV. LSPID TLV.
4. Protocol Specification 4. Protocol Specification
The Label Request Message defined in [1] MUST carry the LSPID TLV The Label Request Message defined in [1] MUST carry the LSPID TLV and
and MAY carry one or more of the optional Constraint-based Routing MAY carry one or more of the optional Constraint-based Routing TLVs
TLVs (CR-TLVs) defined in this section. If needed, other constraints (CR-TLVs) defined in this section. If needed, other constraints can
can be supported later through the definition of new TLVs. In this be supported later through the definition of new TLVs. In this
specification, the following TLVs are defined: specification, the following TLVs are defined:
- Explicit Route TLV - Explicit Route TLV
- Explicit Route Hop TLV - Explicit Route Hop TLV
- Traffic Parameters TLV - Traffic Parameters TLV
- Preemption TLV - Preemption TLV
- LSPID TLV - LSPID TLV
- Route Pinning TLV
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 10 - Resource Class TLV
- Route Pinning TLV - CR-LSP FEC TLV
- Resource Class TLV
- CR-LSP FEC TLV
4.1 Explicit Route TLV (ER-TLV) 4.1 Explicit Route TLV (ER-TLV)
The ER-TLV is an object that specifies the path to be taken by the The ER-TLV is an object that specifies the path to be taken by the
LSP being established. It is composed of one or more Explicit Route LSP being established. It is composed of one or more Explicit Route
Hop TLVs (ER-Hop TLVs) defined in Section 4.2. Hop TLVs (ER-Hop TLVs) defined in Section 4.2.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type = 0x0800 | Length | |0|0| Type = 0x0800 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV 1 | | ER-Hop TLV 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV 2 | | ER-Hop TLV 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ............ ~ ~ ............ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV n | | ER-Hop TLV n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the ER-TLV Type = A fourteen-bit field carrying the value of the ER-TLV
0x0800. Type = 0x0800.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
ER-Hop TLVs ER-Hop TLVs
One or more ER-Hop TLVs defined in Section 4.2. One or more ER-Hop TLVs defined in Section 4.2.
4.2 Explicit Route Hop TLV (ER-Hop TLV) 4.2 Explicit Route Hop TLV (ER-Hop TLV)
The contents of an ER-TLV are a series of variable length ER-Hop The contents of an ER-TLV are a series of variable length ER-Hop
TLVs. TLVs.
A node receiving a label request message including an ER-Hop type A node receiving a label request message including an ER-Hop type
that is not supported MUST not progress the label request message to that is not supported MUST not progress the label request message to
the downstream LSR and MUST send back a "No Route" Notification the downstream LSR and MUST send back a "No Route" Notification
Message. Message.
Each ER-Hop TLV has the form: Each ER-Hop TLV has the form:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type | Length | |0|0| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Content // | |L| Content // |
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 11
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
ER-Hop Type ER-Hop Type
A fourteen-bit field carrying the type of the ER-Hop contents. A fourteen-bit field carrying the type of the ER-Hop contents.
Currently defined values are: Currently defined values are:
Value Type Value Type
------ ------------------------ ------ ------------------------
0x0801 IPv4 prefix 0x0801 IPv4 prefix
0x0802 IPv6 prefix 0x0802 IPv6 prefix
0x0803 Autonomous system number 0x0803 Autonomous system number
0x0804 LSPID 0x0804 LSPID
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
L bit L bit
The L bit in the ER-Hop is a one-bit attribute. If the L bit The L bit in the ER-Hop is a one-bit attribute. If the L bit
is set, then the value of the attribute is "loose." Otherwise, is set, then the value of the attribute is "loose." Otherwise,
the value of the attribute is "strict." For brevity, we say the value of the attribute is "strict." For brevity, we say
that if the value of the ER-Hop attribute is loose then it is a that if the value of the ER-Hop attribute is loose then it is a
"loose ER-Hop." Otherwise, it's a "strict ER-Hop." Further, "loose ER-Hop." Otherwise, it's a "strict ER-Hop." Further,
we say that the abstract node of a strict or loose ER-Hop is a we say that the abstract node of a strict or loose ER-Hop is a
strict or a loose node, respectively. Loose and strict nodes strict or a loose node, respectively. Loose and strict nodes
are always interpreted relative to their prior abstract nodes. are always interpreted relative to their prior abstract nodes.
The path between a strict node and its prior node MUST include The path between a strict node and its prior node MUST include
only network nodes from the strict node and its prior abstract only network nodes from the strict node and its prior abstract
node. node.
The path between a loose node and its prior node MAY include The path between a loose node and its prior node MAY include
other network nodes, which are not part of the strict node or other network nodes, which are not part of the strict node or
its prior abstract node. its prior abstract node.
Contents Contents
A variable length field containing a node or abstract node A variable length field containing a node or abstract node
which is one of the consecutive nodes that make up the which is one of the consecutive nodes that make up the
explicitly routed LSP. explicitly routed LSP.
4.3 Traffic Parameters TLV 4.3 Traffic Parameters TLV
The following sections describe the CR-LSP Traffic Parameters. The The following sections describe the CR-LSP Traffic Parameters. The
required characteristics of a CR-LSP are expressed by the Traffic required characteristics of a CR-LSP are expressed by the Traffic
Parameter values. Parameter values.
A Traffic Parameters TLV, is used to signal the Traffic Parameter A Traffic Parameters TLV, is used to signal the Traffic Parameter
values. The Traffic Parameters are defined in the subsequent values. The Traffic Parameters are defined in the subsequent
sections. sections.
The Traffic Parameters TLV contains a Flags field, a Frequency, a The Traffic Parameters TLV contains a Flags field, a Frequency, a
Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS. Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS.
The Traffic Parameters TLV is shown below:
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 12
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type = 0x0810 | Length = 24 | |0|0| Type = 0x0810 | Length = 24 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Frequency | Reserved | Weight | | Flags | Frequency | Reserved | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Data Rate (PDR) | | Peak Data Rate (PDR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Burst Size (PBS) | | Peak Burst Size (PBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Data Rate (CDR) | | Committed Data Rate (CDR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Burst Size (CBS) | | Committed Burst Size (CBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Excess Burst Size (EBS) | | Excess Burst Size (EBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the Traffic A fourteen-bit field carrying the value of the Traffic
Parameters TLV Type = 0x0810. Parameters TLV Type = 0x0810.
Length Length
Specifies the length of the value field in bytes = 24. Specifies the length of the value field in bytes = 24.
Flags Flags
The Flags field is shown below: The Flags field is shown below:
+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+
| Res |F6|F5|F4|F3|F2|F1| | Res |F6|F5|F4|F3|F2|F1|
+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+
Res - These bits are reserved. Res - These bits are reserved.
Zero on transmission. Zero on transmission.
Ignored on receipt. Ignored on receipt.
F1 - Corresponds to the PDR. F1 - Corresponds to the PDR.
F2 - Corresponds to the PBS. F2 - Corresponds to the PBS.
F3 - Corresponds to the CDR. F3 - Corresponds to the CDR.
F4 - Corresponds to the CBS. F4 - Corresponds to the CBS.
F5 - Corresponds to the EBS. F5 - Corresponds to the EBS.
F6 - Corresponds to the Weight. F6 - Corresponds to the Weight.
Each flag Fi is a Negotiable Flag corresponding to a Traffic Each flag Fi is a Negotiable Flag corresponding to a Traffic
Parameter. The Negotiable Flag value zero denotes NotNegotiable Parameter. The Negotiable Flag value zero denotes
and value one denotes Negotiable. NotNegotiable and value one denotes Negotiable.
Frequency Frequency
The Frequency field is coded as an 8 bit unsigned integer with The Frequency field is coded as an 8 bit unsigned integer with
the following code points defined: the following code points defined:
0- Unspecified
1- Frequent
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 13 0- Unspecified
2- VeryFrequent 1- Frequent
3-255 - Reserved 2- VeryFrequent
Reserved - Zero on transmission. Ignored on receipt. 3-255 - Reserved
Reserved - Zero on transmission. Ignored on receipt.
Weight Weight
An 8 bit unsigned integer indicating the weight of the CR-LSP. An 8 bit unsigned integer indicating the weight of the CR-LSP.
Valid weight values are from 1 to 255. The value 0 means that Valid weight values are from 1 to 255. The value 0 means that
weight is not applicable for the CR-LSP. weight is not applicable for the CR-LSP.
Traffic Parameters Traffic Parameters
Each Traffic Parameter is encoded as a 32-bit IEEE single- Each Traffic Parameter is encoded as a 32-bit IEEE single-
precision floating-point number. A value of positive infinity precision floating-point number. A value of positive infinity
is represented as an IEEE single-precision floating-point is represented as an IEEE single-precision floating-point
number with an exponent of all ones (255) and a sign and number with an exponent of all ones (255) and a sign and
mantissa of all zeros. The values PDR and CDR are in units of mantissa of all zeros. The values PDR and CDR are in units of
bytes per second. The values PBS, CBS and EBS are in units of bytes per second. The values PBS, CBS and EBS are in units of
bytes. bytes.
The value of PDR MUST be greater than or equal to the value of The value of PDR MUST be greater than or equal to the value of
CDR in a correctly encoded Traffic Parameters TLV. CDR in a correctly encoded Traffic Parameters TLV.
4.3.1 Semantics 4.3.1 Semantics
4.3.1.1 Frequency 4.3.1.1 Frequency
The Frequency specifies at what granularity the CDR allocated to the The Frequency specifies at what granularity the CDR allocated to the
CR-LSP is made available. The value VeryFrequent means that the CR-LSP is made available. The value VeryFrequent means that the
available rate should average at least the CDR when measured over available rate should average at least the CDR when measured over any
any time interval equal to or longer than the shortest packet time time interval equal to or longer than the shortest packet time at the
at the CDR. The value Frequent means that the available rate should CDR. The value Frequent means that the available rate should average
average at least the CDR when measured over any time interval equal at least the CDR when measured over any time interval equal to or
to or longer than a small number of shortest packet times at the longer than a small number of shortest packet times at the CDR.
CDR.
The value Unspecified means that the CDR MAY be provided at any The value Unspecified means that the CDR MAY be provided at any
granularity. granularity.
4.3.1.2 Peak Rate 4.3.1.2 Peak Rate
The Peak Rate defines the maximum rate at which traffic SHOULD be The Peak Rate defines the maximum rate at which traffic SHOULD be
sent to the CR-LSP. The Peak Rate is useful for the purpose of sent to the CR-LSP. The Peak Rate is useful for the purpose of
resource allocation. If resource allocation within the MPLS domain resource allocation. If resource allocation within the MPLS domain
depends on the Peak Rate value then it should be enforced at the depends on the Peak Rate value then it should be enforced at the
ingress to the MPLS domain. ingress to the MPLS domain.
The Peak Rate is defined in terms of the two Traffic Parameters PDR The Peak Rate is defined in terms of the two Traffic Parameters PDR
and PBS, see section 4.3.1.5 below. and PBS, see section 4.3.1.5 below.
4.3.1.3 Committed Rate 4.3.1.3 Committed Rate
The Committed Rate defines the rate that the MPLS domain commits to The Committed Rate defines the rate that the MPLS domain commits to
be available to the CR-LSP. be available to the CR-LSP.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 14
The Committed Rate is defined in terms of the two Traffic Parameters The Committed Rate is defined in terms of the two Traffic Parameters
CDR and CBS, see section 4.3.1.6 below. CDR and CBS, see section 4.3.1.6 below.
4.3.1.4 Excess Burst Size 4.3.1.4 Excess Burst Size
The Excess Burst Size may be used at the edge of an MPLS domain for The Excess Burst Size may be used at the edge of an MPLS domain for
the purpose of traffic conditioning. The EBS MAY be used to measure the purpose of traffic conditioning. The EBS MAY be used to measure
the extent by which the traffic sent on a CR-LSP exceeds the the extent by which the traffic sent on a CR-LSP exceeds the
committed rate. committed rate.
The possible traffic conditioning actions, such as passing, marking The possible traffic conditioning actions, such as passing, marking
or dropping, are specific to the MPLS domain. or dropping, are specific to the MPLS domain.
The Excess Burst Size is defined together with the Committed Rate, The Excess Burst Size is defined together with the Committed Rate,
see section 4.3.1.6 below. see section 4.3.1.6 below.
4.3.1.5 Peak Rate Token Bucket 4.3.1.5 Peak Rate Token Bucket
The Peak Rate of a CR-LSP is specified in terms of a token bucket P The Peak Rate of a CR-LSP is specified in terms of a token bucket P
with token rate PDR and maximum token bucket size PBS. with token rate PDR and maximum token bucket size PBS.
The token bucket P is initially (at time 0) full, i.e., the token The token bucket P is initially (at time 0) full, i.e., the token
count Tp(0) = PBS. Thereafter, the token count Tp, if less than count Tp(0) = PBS. Thereafter, the token count Tp, if less than PBS,
PBS, is incremented by one PDR times per second. When a packet of is incremented by one PDR times per second. When a packet of size B
size B bytes arrives at time t, the following happens: bytes arrives at time t, the following happens:
- If Tp(t)-B >= 0, the packet is not in excess of the peak rate - If Tp(t)-B >= 0, the packet is not in excess of the peak rate
and Tp is decremented by B down to the minimum value of 0, else and Tp is decremented by B down to the minimum value of 0, else
- the packet is in excess of the peak rate and Tp is not - the packet is in excess of the peak rate and Tp is not
decremented. decremented.
Note that according to the above definition, a positive infinite Note that according to the above definition, a positive infinite
value of either PDR or PBS implies that arriving packets are never value of either PDR or PBS implies that arriving packets are never in
in excess of the peak rate. excess of the peak rate.
The actual implementation of an LSR doesn't need to be modeled The actual implementation of an LSR doesn't need to be modeled
according to the above formal token bucket specification. according to the above formal token bucket specification.
4.3.1.6 Committed Data Rate Token Bucket 4.3.1.6 Committed Data Rate Token Bucket
The committed rate of a CR-LSP is specified in terms of a token The committed rate of a CR-LSP is specified in terms of a token
bucket C with rate CDR. The extent by which the offered rate bucket C with rate CDR. The extent by which the offered rate exceeds
exceeds the committed rate MAY be measured in terms of another token the committed rate MAY be measured in terms of another token bucket
bucket E, which also operates at rate CDR. The maximum size of the E, which also operates at rate CDR. The maximum size of the token
token bucket C is CBS and the maximum size of the token bucket E is bucket C is CBS and the maximum size of the token bucket E is EBS.
EBS.
The token buckets C and E are initially (at time 0) full, i.e., the The token buckets C and E are initially (at time 0) full, i.e., the
token count Tc(0) = CBS and the token count Te(0) = EBS. token count Tc(0) = CBS and the token count Te(0) = EBS.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 15
Thereafter, the token counts Tc and Te are updated CDR times per Thereafter, the token counts Tc and Te are updated CDR times per
second as follows: second as follows:
- If Tc is less than CBS, Tc is incremented by one, else - If Tc is less than CBS, Tc is incremented by one, else
- if Te is less then EBS, Te is incremented by one, else - if Te is less then EBS, Te is incremented by one, else neither
neither Tc nor Te is incremented. Tc nor Te is incremented.
When a packet of size B bytes arrives at time t, the following When a packet of size B bytes arrives at time t, the following
happens: happens:
- If Tc(t)-B >= 0, the packet is not in excess of the Committed - If Tc(t)-B >= 0, the packet is not in excess of the Committed
Rate and Tc is decremented by B down to the minimum value of 0, Rate and Tc is decremented by B down to the minimum value of 0,
else else
- if Te(t)-B >= 0, the packet is in excess of the Committed rate - if Te(t)-B >= 0, the packet is in excess of the Committed rate
but is not in excess of the EBS and Te is decremented by B down to but is not in excess of the EBS and Te is decremented by B down
the minimum value of 0, else to the minimum value of 0, else
- the packet is in excess of both the Committed Rate and the EBS - the packet is in excess of both the Committed Rate and the EBS
and neither Tc nor Te is decremented. and neither Tc nor Te is decremented.
Note that according to the above specification, a CDR value of Note that according to the above specification, a CDR value of
positive infinity implies that arriving packets are never in excess positive infinity implies that arriving packets are never in excess
of either the Committed Rate or EBS. A positive infinite value of of either the Committed Rate or EBS. A positive infinite value of
either CBS or EBS implies that the respective limit cannot be either CBS or EBS implies that the respective limit cannot be
exceeded. exceeded.
The actual implementation of an LSR doesn't need to be modeled The actual implementation of an LSR doesn't need to be modeled
according to the above formal specification. according to the above formal specification.
4.3.1.7 Weight 4.3.1.7 Weight
The weight determines the CR-LSP's relative share of the possible The weight determines the CR-LSP's relative share of the possible
excess bandwidth above its committed rate. The definition of excess bandwidth above its committed rate. The definition of
skipping to change at line 821 skipping to change at page 18, line 25
If an LSR receives an incorrectly encoded Traffic Parameters TLV in If an LSR receives an incorrectly encoded Traffic Parameters TLV in
which the value of PDR is less than the value of CDR then it MUST which the value of PDR is less than the value of CDR then it MUST
send a Notification Message including the Status code "Traffic send a Notification Message including the Status code "Traffic
Parameters Unavailable" to the upstream LSR from which it received Parameters Unavailable" to the upstream LSR from which it received
the erroneous message. the erroneous message.
If a Traffic Parameter is indicated as Negotiable in the Label If a Traffic Parameter is indicated as Negotiable in the Label
Request Message by the corresponding Negotiable Flag then an LSR MAY Request Message by the corresponding Negotiable Flag then an LSR MAY
replace the Traffic Parameter value with a smaller value. replace the Traffic Parameter value with a smaller value.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 16 If the Weight is indicated as Negotiable in the Label Request Message
If the Weight is indicated as Negotiable in the Label Request by the corresponding Negotiable Flag then an LSR may replace the
Message by the corresponding Negotiable Flag then an LSR may replace Weight value with a lower value (down to 0).
the Weight value with a lower value (down to 0).
If, after possible Traffic Parameter negotiation, an LSR can support If, after possible Traffic Parameter negotiation, an LSR can support
the CR-LSP Traffic Parameters then the LSR MUST reserve the the CR-LSP Traffic Parameters then the LSR MUST reserve the
corresponding resources for the CR-LSP. corresponding resources for the CR-LSP.
If, after possible Traffic Parameter negotiation, an LSR cannot If, after possible Traffic Parameter negotiation, an LSR cannot
support the CR-LSP Traffic Parameters then the LSR MUST send a support the CR-LSP Traffic Parameters then the LSR MUST send a
Notification Message that contains the "Resource Unavailable" status Notification Message that contains the "Resource Unavailable" status
code. code.
4.3.2.2 Label Mapping Message 4.3.2.2 Label Mapping Message
If an LSR receives an incorrectly encoded Traffic Parameters TLV in If an LSR receives an incorrectly encoded Traffic Parameters TLV in
which the value of PDR is less than the value of CDR then it MUST which the value of PDR is less than the value of CDR then it MUST
send a Label Release message containing the Status code "Traffic send a Label Release message containing the Status code "Traffic
Parameters Unavailable" to the LSR from which it received the Parameters Unavailable" to the LSR from which it received the
erroneous message. In addition, the LSP should send a Notification erroneous message. In addition, the LSP should send a Notification
Message upstream with the status code 'Label Request Aborted'. Message upstream with the status code 'Label Request Aborted'.
If the negotiation flag was set in the label request message, the If the negotiation flag was set in the label request message, the
egress LSR MUST include the (possibly negotiated) Traffic Parameters egress LSR MUST include the (possibly negotiated) Traffic Parameters
and Weight in the Label Mapping message. and Weight in the Label Mapping message.
The Traffic Parameters and the Weight in a Label Mapping message The Traffic Parameters and the Weight in a Label Mapping message MUST
MUST be forwarded unchanged. be forwarded unchanged.
An LSR SHOULD adjust the resources that it reserved for a CR-LSP An LSR SHOULD adjust the resources that it reserved for a CR-LSP when
when it receives a Label Mapping Message if the Traffic Parameters it receives a Label Mapping Message if the Traffic Parameters differ
differ from those in the corresponding Label Request Message. from those in the corresponding Label Request Message.
4.3.2.3 Notification Message 4.3.2.3 Notification Message
If an LSR receives a Notification Message for a CR-LSP, it SHOULD If an LSR receives a Notification Message for a CR-LSP, it SHOULD
release any resources that it possibly had reserved for the CR-LSP. release any resources that it possibly had reserved for the CR-LSP.
In addition, on receiving a Notification Message from a Downstream In addition, on receiving a Notification Message from a Downstream
LSR that is associated with a Label Request from an upstream LSR, LSR that is associated with a Label Request from an upstream LSR, the
the local LSR MUST propagate the Notification message using the local LSR MUST propagate the Notification message using the
procedures in [1]. Further the F bit MUST be set. procedures in [1]. Further the F bit MUST be set.
4.4 Preemption TLV 4.4 Preemption TLV
The defualt value of the setup and holding priorities should be in The default value of the setup and holding priorities should be in
the middle of the range (e.g., 4) so that this feature can be turned the middle of the range (e.g., 4) so that this feature can be turned
on gradually in an operational network by increasing or decreasing on gradually in an operational network by increasing or decreasing
the priority starting at the middle of the range. the priority starting at the middle of the range.
Since the Preemption TLV is an optional TLV, LSPs that are setup Since the Preemption TLV is an optional TLV, LSPs that are setup
without an explicitly signaled preemption TLV SHOULD be treated as without an explicitly signaled preemption TLV SHOULD be treated as
LSPs with the default setup and holding priorities (e.g., 4). LSPs with the default setup and holding priorities (e.g., 4).
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 17
When an established LSP is preempted, the LSR that initiates the When an established LSP is preempted, the LSR that initiates the
preemption sends a Withdraw Message upstream and a Release Message preemption sends a Withdraw Message upstream and a Release Message
downstream. downstream.
When an LSP in the process of being established (outstanding Label When an LSP in the process of being established (outstanding Label
Request without getting a Label Mapping back) is preempted, the LSR Request without getting a Label Mapping back) is preempted, the LSR
that initiates the preemption, sends a Notification Message upstream that initiates the preemption, sends a Notification Message upstream
and an Abort Message downstream. and an Abort Message downstream.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type = 0x0820 | Length = 4 | |0|0| Type = 0x0820 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SetPrio | HoldPrio | Reserved | | SetPrio | HoldPrio | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the Preemption-TLV A fourteen-bit field carrying the value of the Preemption-TLV
Type = 0x0820. Type = 0x0820.
Length Length
Specifies the length of the value field in bytes = 4. Specifies the length of the value field in bytes = 4.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
SetPrio SetPrio
A SetupPriority of value zero (0) is the priority assigned to A SetupPriority of value zero (0) is the priority assigned to
the most important path. It is referred to as the highest the most important path. It is referred to as the highest
priority. Seven (7) is the priority for the least important priority. Seven (7) is the priority for the least important
path. The higher the setup priority, the more paths CR-LDP can path. The higher the setup priority, the more paths CR-LDP can
bump to set up the path. The default value should be 4. bump to set up the path. The default value should be 4.
HoldPrio HoldPrio
A HoldingPriority of value zero (0) is the priority assigned to A HoldingPriority of value zero (0) is the priority assigned to
the most important path. It is referred to as the highest the most important path. It is referred to as the highest
priority. Seven (7) is the priority for the least important priority. Seven (7) is the priority for the least important
path. The default value should be 4. path. The default value should be 4.
The higher the holding priority, the less likely it is for CR- The higher the holding priority, the less likely it is for CR-
LDP to reallocate its bandwidth to a new path. LDP to reallocate its bandwidth to a new path.
4.5 LSPID TLV 4.5 LSPID TLV
LSPID is a unique identifier of a CR-LSP within an MPLS network. LSPID is a unique identifier of a CR-LSP within an MPLS network.
The LSPID is composed of the ingress LSR Router ID (or any of its The LSPID is composed of the ingress LSR Router ID (or any of its
own Ipv4 addresses) and a Locally unique CR-LSP ID to that LSR. own Ipv4 addresses) and a Locally unique CR-LSP ID to that LSR.
The LSPID is useful in network management, in CR-LSP repair, and in The LSPID is useful in network management, in CR-LSP repair, and in
using an already established CR-LSP as a hop in an ER-TLV. using an already established CR-LSP as a hop in an ER-TLV.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 18 An "action indicator flag" is carried in the LSPID TLV. This "action
An "action indicator flag" is carried in the LSPID TLV. This "action
indicator flag" indicates explicitly the action that should be taken indicator flag" indicates explicitly the action that should be taken
if the LSP already exists on the LSR receiving the message. if the LSP already exists on the LSR receiving the message.
After a CR-LSP is set up, its bandwidth reservation may need to be After a CR-LSP is set up, its bandwidth reservation may need to be
changed by the network operator, due to the new requirements for the changed by the network operator, due to the new requirements for the
traffic carried on that CR-LSP. The "action indicator flag" is used traffic carried on that CR-LSP. The "action indicator flag" is used
indicate the need to modify the bandwidth and possibly other indicate the need to modify the bandwidth and possibly other
parameters of an established CR-LSP without service interruption. parameters of an established CR-LSP without service interruption.
This feature has application in dynamic network resources management This feature has application in dynamic network resources management
where traffic of different priorities and service classes is where traffic of different priorities and service classes is
involved. involved.
The procedure for the code point "modify" is defined in [8]. The The procedure for the code point "modify" is defined in [8]. The
procedures for other flags are FFS. procedures for other flags are FFS.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type = 0x0821 | Length = 4 | |0|0| Type = 0x0821 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |ActFlg | Local CR-LSP ID | | Reserved |ActFlg | Local CR-LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ingress LSR Router ID | | Ingress LSR Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the LSPID-TLV A fourteen-bit field carrying the value of the LSPID-TLV
Type = 0x0821. Type = 0x0821.
Length Length
Specifies the length of the value field in bytes = 4. Specifies the length of the value field in bytes = 4.
ActFlg ActFlg
Action Indicator Flag: A 4-bit field that indicates explicitly Action Indicator Flag: A 4-bit field that indicates explicitly
the action that should be taken if the LSP already exists on the action that should be taken if the LSP already exists on
the LSR receiving the message. A set of indicator code points the LSR receiving the message. A set of indicator code points
is proposed as follows: is proposed as follows:
0000: indicates initial LSP setup
0001: indicates modify LSP
0000: indicates initial LSP setup
0001: indicates modify LSP
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
Local CR-LSP ID Local CR-LSP ID
The Local LSP ID is an identifier of the CR-LSP locally unique The Local LSP ID is an identifier of the CR-LSP locally unique
within the Ingress LSR originating the CR-LSP. within the Ingress LSR originating the CR-LSP.
Ingress LSR Router ID Ingress LSR Router ID
An LSR may use any of its own IPv4 addresses in this field. An LSR may use any of its own IPv4 addresses in this field.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 19
4.6 Resource Class (Color) TLV 4.6 Resource Class (Color) TLV
The Resource Class as defined in [3] is used to specify which links The Resource Class as defined in [3] is used to specify which links
are acceptable by this CR-LSP. This information allows for the are acceptable by this CR-LSP. This information allows for the
network's topology to be pruned. network's topology to be pruned.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type = 0x0822 | Length = 4 | |0|0| Type = 0x0822 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RsCls | | RsCls |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the ResCls-TLV Type A fourteen-bit field carrying the value of the ResCls-TLV
= 0x0822. Type = 0x0822.
Length Length
Specifies the length of the value field in bytes = 4. Specifies the length of the value field in bytes = 4.
RsCls RsCls
The Resource Class bit mask indicating which of the 32 The Resource Class bit mask indicating which of the 32
"administrative groups" or "colors" of links the CR-LSP can "administrative groups" or "colors" of links the CR-LSP can
traverse. traverse.
4.7 ER-Hop semantics 4.7 ER-Hop semantics
4.7.1. ER-Hop 1: The IPv4 prefix 4.7.1. ER-Hop 1: The IPv4 prefix
The abstract node represented by this ER-Hop is the set of nodes, The abstract node represented by this ER-Hop is the set of nodes,
which have an IP address, which lies within this prefix. Note that which have an IP address, which lies within this prefix. Note that a
a prefix length of 32 indicates a single IPv4 node. prefix length of 32 indicates a single IPv4 node.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type = 0x0801 | Length = 8 | |0|0| Type = 0x0801 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | PreLen | |L| Reserved | PreLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address (4 bytes) | | IPv4 Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the ER-Hop 1, IPv4 A fourteen-bit field carrying the value of the ER-Hop 1, IPv4
Address, Type = 0x0801 Address, Type = 0x0801
Length Length
Specifies the length of the value field in bytes = 8. Specifies the length of the value field in bytes = 8.
L Bit L Bit
Set to indicate Loose hop.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 20 Cleared to indicate a strict hop.
Set to indicate Loose hop.
Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
PreLen PreLen
Prefix Length 1-32 Prefix Length 1-32
IP Address IP Address
A four-byte field indicating the IP Address. A four-byte field indicating the IP Address.
4.7.2. ER-Hop 2: The IPv6 address 4.7.2. ER-Hop 2: The IPv6 address
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| 0x0802 | Length = 20 | |0|0| 0x0802 | Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | PreLen | |L| Reserved | PreLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address | | IPV6 address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the ER-Hop 2, IPv6 A fourteen-bit field carrying the value of the ER-Hop 2, IPv6
Address, Type = 0x0802 Address, Type = 0x0802
Length Length
Specifies the length of the value field in bytes = 20. Specifies the length of the value field in bytes = 20.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
PreLen PreLen
Prefix Length 1-128 Prefix Length 1-128
IPv6 address IPv6 address
A 128-bit unicast host address. A 128-bit unicast host address.
4.7.3. ER-Hop 3: The autonomous system number 4.7.3. ER-Hop 3: The autonomous system number
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 21
The abstract node represented by this ER-Hop is the set of nodes The abstract node represented by this ER-Hop is the set of nodes
belonging to the autonomous system. belonging to the autonomous system.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| 0x0803 | Length = 4 | |0|0| 0x0803 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | AS Number | |L| Reserved | AS Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the ER-Hop 3, AS A fourteen-bit field carrying the value of the ER-Hop 3, AS
Number, Type = 0x0803 Number, Type = 0x0803
Length Length
Specifies the length of the value field in bytes = 4. Specifies the length of the value field in bytes = 4.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
AS Number AS Number
Autonomous System number Autonomous System number
4.7.4. ER-Hop 4: LSPID 4.7.4. ER-Hop 4: LSPID
The LSPID is used to identify the tunnel ingress point as the next The LSPID is used to identify the tunnel ingress point as the next
hop in the ER. This ER-Hop allows for stacking new CR-LSPs within an hop in the ER. This ER-Hop allows for stacking new CR-LSPs within an
already established CR-LSP. It also allows for splicing the CR-LSP already established CR-LSP. It also allows for splicing the CR-LSP
being established with an existing CR-LSP. being established with an existing CR-LSP.
If an LSPID Hop is the last ER-Hop in an ER-TLV, than the LSR may If an LSPID Hop is the last ER-Hop in an ER-TLV, than the LSR may
splice the CR-LSP of the incoming Label Request to the CR-LSP that splice the CR-LSP of the incoming Label Request to the CR-LSP that
currently exists with this LSPID. This is useful, for example, at currently exists with this LSPID. This is useful, for example, at
the point at which a Label Request used for local repair arrives at the point at which a Label Request used for local repair arrives at
the next ER-Hop after the loosely specified CR-LSP segment. Use of the next ER-Hop after the loosely specified CR-LSP segment. Use of
the LSPID Hop in this scenario eliminates the need for ER-Hops to the LSPID Hop in this scenario eliminates the need for ER-Hops to
keep the entire remaining ER-TLV at each LSR that is at either keep the entire remaining ER-TLV at each LSR that is at either
(upstream or downstream) end of a loosely specified CR-LSP segment (upstream or downstream) end of a loosely specified CR-LSP segment as
as part of its state information. This is due to the fact that the part of its state information. This is due to the fact that the
upstream LSR needs only to keep the next ER-Hop and the LSPID and upstream LSR needs only to keep the next ER-Hop and the LSPID and the
the downstream LSR needs only to keep the LSPID in order for each downstream LSR needs only to keep the LSPID in order for each end to
end to be able to recognize that the same LSP is being identified. be able to recognize that the same LSP is being identified.
If the LSPID Hop is not the last hop in an ER-TLV, the LSR must If the LSPID Hop is not the last hop in an ER-TLV, the LSR must
remove the LSP-ID Hop and forward the remaining ER-TLV in a Label remove the LSP-ID Hop and forward the remaining ER-TLV in a Label
Request message using an LDP session established with the LSR that Request message using an LDP session established with the LSR that is
is the specified CR-LSP's egress. That LSR will continue processing the specified CR-LSP's egress. That LSR will continue processing of
the CR-LSP Label Request Message. The result is a tunneled, or
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 22
of the CR-LSP Label Request Message. The result is a tunneled, or
stacked, CR-LSP. stacked, CR-LSP.
To support labels negotiated for tunneled CR-LSP segments, an LDP To support labels negotiated for tunneled CR-LSP segments, an LDP
session is required [1] between tunnel end points - possibly using session is required [1] between tunnel end points - possibly using
the existing CR-LSP. Use of the existence of the CR-LSP in lieu of the existing CR-LSP. Use of the existence of the CR-LSP in lieu of a
a session, or other possible session-less approaches, is FFS. session, or other possible session-less approaches, is FFS.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| 0x0804 | Length = 8 | |0|0| 0x0804 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | Local LSPID | |L| Reserved | Local LSPID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ingress LSR Router ID | | Ingress LSR Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the ER-Hop 4, LSPID, A fourteen-bit field carrying the value of the ER-Hop 4, LSPID,
Type = 0x0804 Type = 0x0804
Length Length
Specifies the length of the value field in bytes = 8. Specifies the length of the value field in bytes = 8.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
Local LSPID Local LSPID
A 2 byte field indicating the LSPID which is unique with A 2 byte field indicating the LSPID which is unique with
reference to its Ingress LSR. reference to its Ingress LSR.
Ingress LSR Router ID Ingress LSR Router ID
An LSR may use any of its own IPv4 addresses in this field. An LSR may use any of its own IPv4 addresses in this field.
4.8. Processing of the Explicit Route TLV 4.8. Processing of the Explicit Route TLV
4.8.1. Selection of the next hop 4.8.1. Selection of the next hop
A Label Request Message containing an explicit route TLV must A Label Request Message containing an explicit route TLV must
determine the next hop for this path. Selection of this next hop determine the next hop for this path. Selection of this next hop may
may involve a selection from a set of possible alternatives. The involve a selection from a set of possible alternatives. The
mechanism for making a selection from this set is implementation mechanism for making a selection from this set is implementation
dependent and is outside of the scope of this specification. dependent and is outside of the scope of this specification.
Selection of particular paths is also outside of the scope of this Selection of particular paths is also outside of the scope of this
specification, but it is assumed that each node will make a best specification, but it is assumed that each node will make a best
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 23
effort attempt to determine a loop-free path. Note that such best effort attempt to determine a loop-free path. Note that such best
efforts may be overridden by local policy. efforts may be overridden by local policy.
To determine the next hop for the path, a node performs the To determine the next hop for the path, a node performs the following
following steps: steps:
1. The node receiving the Label Request Message must first 1. The node receiving the Label Request Message must first
evaluate the first ER-Hop. If the L bit is not set in the first evaluate the first ER-Hop. If the L bit is not set in the
ER-Hop and if the node is not part of the abstract node described first ER-Hop and if the node is not part of the abstract node
by the first ER-Hop, it has received the message in error, and described by the first ER-Hop, it has received the message in
should return a "Bad Initial ER-Hop" error. If the L bit is set error, and should return a "Bad Initial ER-Hop Error" status.
and the local node is not part of the abstract node described by If the L bit is set and the local node is not part of the
the first ER-Hop, the node selects a next hop that is along the abstract node described by the first ER-Hop, the node selects a
path to the abstract node described by the first ER-Hop. If there next hop that is along the path to the abstract node described
is no first ER-Hop, the message is also in error and the system by the first ER-Hop. If there is no first ER-Hop, the message
should return a "Bad Explicit Routing TLV" error using a is also in error and the system should return a "Bad Explicit
Notification Message sent upstream. Routing TLV Error" status using a Notification Message sent
upstream.
2. If there is no second ER-Hop, this indicates the end of the 2. If there is no second ER-Hop, this indicates the end of the
explicit route. The explicit route TLV should be removed from the explicit route. The explicit route TLV should be removed from
Label Request Message. This node may or may not be the end of the Label Request Message. This node may or may not be the end
the LSP. Processing continues with section 4.8.2, where a new of the LSP. Processing continues with section 4.8.2, where a
explicit route TLV may be added to the Label Request Message. new explicit route TLV may be added to the Label Request
Message.
3. If the node is also a part of the abstract node described by 3. If the node is also a part of the abstract node described by
the second ER-Hop, then the node deletes the first ER-Hop and the second ER-Hop, then the node deletes the first ER-Hop and
continues processing with step 2, above. Note that this makes continues processing with step 2, above. Note that this makes
the second ER-Hop into the first ER-Hop of the next iteration. the second ER-Hop into the first ER-Hop of the next iteration.
4. The node determines if it is topologically adjacent to the 4. The node determines if it is topologically adjacent to the
abstract node described by the second ER-Hop. If so, the node abstract node described by the second ER-Hop. If so, the node
selects a particular next hop which is a member of the abstract selects a particular next hop which is a member of the abstract
node. The node then deletes the first ER-Hop and continues node. The node then deletes the first ER-Hop and continues
processing with section 4.8.2. processing with section 4.8.2.
5. Next, the node selects a next hop within the abstract node of 5. Next, the node selects a next hop within the abstract node of
the first ER-Hop that is along the path to the abstract node of the first ER-Hop that is along the path to the abstract node of
the second ER-Hop. If no such path exists then there are two the second ER-Hop. If no such path exists then there are two
cases: cases:
5.a If the second ER-Hop is a strict ER-Hop, then there is 5.a If the second ER-Hop is a strict ER-Hop, then there is an
an error and the node should return a "Bad Strict Node" error and the node should return a "Bad Strict Node Error"
error. status.
5.b Otherwise, if the second ER-Hop is a loose ER-Hop, then 5.b Otherwise, if the second ER-Hop is a loose ER-Hop, then the
the node selects any next hop that is along the path to the node selects any next hop that is along the path to the
next abstract node. If no path exists within the MPLS next abstract node. If no path exists within the MPLS
domain, then there is an error, and the node should return a domain, then there is an error, and the node should return
"Bad loose node" error. a "Bad Loose Node Error" status.
6. Finally, the node replaces the first ER-Hop with any ER-Hop 6. Finally, the node replaces the first ER-Hop with any ER-Hop
that denotes an abstract node containing the next hop. This is that denotes an abstract node containing the next hop. This is
necessary so that when the explicit route is received by the
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 24 next hop, it will be accepted.
necessary so that when the explicit route is received by the next
hop, it will be accepted.
7. Progress the Label Request Message to the next hop. 7. Progress the Label Request Message to the next hop.
4.8.2. Adding ER-Hops to the explicit route TLV 4.8.2. Adding ER-Hops to the explicit route TLV
After selecting a next hop, the node may alter the explicit route in After selecting a next hop, the node may alter the explicit route in
the following ways. the following ways.
If, as part of executing the algorithm in section 4.8.1, the If, as part of executing the algorithm in section 4.8.1, the explicit
explicit route TLV is removed, the node may add a new explicit route route TLV is removed, the node may add a new explicit route TLV.
TLV.
Otherwise, if the node is a member of the abstract node for the Otherwise, if the node is a member of the abstract node for the first
first ER-Hop, then a series of ER-Hops may be inserted before the ER-Hop, then a series of ER-Hops may be inserted before the first
first ER-Hop or may replace the first ER-Hop. Each ER-Hop in this ER-Hop or may replace the first ER-Hop. Each ER-Hop in this series
series must denote an abstract node that is a subset of the current must denote an abstract node that is a subset of the current abstract
abstract node. node.
Alternately, if the first ER-Hop is a loose ER-Hop, an arbitrary Alternately, if the first ER-Hop is a loose ER-Hop, an arbitrary
series of ER-Hops may be inserted prior to the first ER-Hop. series of ER-Hops may be inserted prior to the first ER-Hop.
4.9 Route Pinning TLV 4.9 Route Pinning TLV
Section 2.4 describes the use of route pinning. The encoding of the Section 2.4 describes the use of route pinning. The encoding of the
Route Pinning TLV is as follows: Route Pinning TLV is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type = 0x0823 | Length = 4 | |0|0| Type = 0x0823 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P| Reserved | |P| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the Pinning-TLV A fourteen-bit field carrying the value of the Pinning-TLV
Type = 0x0823 Type = 0x0823
Length Length
Specifies the length of the value field in bytes = 4. Specifies the length of the value field in bytes = 4.
P Bit P Bit
The P bit is set to 1 to indicate that route pinning is The P bit is set to 1 to indicate that route pinning is
requested. requested.
The P bit is set to 0 to indicate that route pinning is not The P bit is set to 0 to indicate that route pinning is not
requested requested
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 25
4.10 CR-LSP FEC Element 4.10 CR-LSP FEC Element
A new FEC element is introduced in this specification to support CR- A new FEC element is introduced in this specification to support CR-
LSPs. A FEC TLV containing a FEC of Element type CR-LSP (0x04) is a LSPs. A FEC TLV containing a FEC of Element type CR-LSP (0x04) is a
CR-LSP FEC TLV. The CR-LSP FEC Element is an opaque FEC to be used CR-LSP FEC TLV. The CR-LSP FEC Element is an opaque FEC to be used
only in Messages of CR-LSPs. only in Messages of CR-LSPs.
A single FEC element MUST be included in the Label Request Message. A single FEC element MUST be included in the Label Request Message.
The FEC Element SHOULD be the CR-LSP FEC Element. However, one of The FEC Element SHOULD be the CR-LSP FEC Element. However, one of
the other FEC elements (Type=0x01, 0x02, 0x03) defined in [1] MAY be the other FEC elements (Type=0x01, 0x02, 0x03) defined in [1] MAY be
in CR-LDP messages instead of the CR-LSP FEC Element for certain in CR-LDP messages instead of the CR-LSP FEC Element for certain
applications. A FEC TLV containing a FEC of Element type CR-LSP applications. A FEC TLV containing a FEC of Element type CR-LSP
(0x04) is a CR-LSP FEC TLV. (0x04) is a CR-LSP FEC TLV.
FEC Element Type Value FEC Element Type Value
Type name Type name
CR-LSP 0x04 No value; i.e., 0 value octets; CR-LSP 0x04 No value; i.e., 0 value octets;
The CR-LSP FEC TLV encoding is as follows: The CR-LSP FEC TLV encoding is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type = 0x0100 | Length = 1 | |0|0| Type = 0x0100 | Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CR-LSP (4) | | CR-LSP (4) |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the FEC TLV A fourteen-bit field carrying the value of the FEC TLV
Type = 0x0100 Type = 0x0100
Length Length
Specifies the length of the value field in bytes = 1. Specifies the length of the value field in bytes = 1.
CR-LSP FEC Element Type CR-LSP FEC Element Type
0x04 0x04
5. IANA Considerations 5. IANA Considerations
CR-LDP defines the following name spaces, which require management: CR-LDP defines the following name spaces, which require management:
- TLV types. - TLV types.
- FEC types. - FEC types.
- Status codes. - Status codes.
The following sections provide guidelines for managing these name The following sections provide guidelines for managing these name
spaces. spaces.
5.1 TLV Type Name Space 5.1 TLV Type Name Space
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 26 RFC 3036 [1] defines the LDP TLV name space. This document further
RFC 3036 [1] defines the LDP TLV name space. This document further
subdivides the range of RFC 3036 from that TLV space for TLVs subdivides the range of RFC 3036 from that TLV space for TLVs
associated with the CR-LDP in the range 0x0800 - 0x08FF. associated with the CR-LDP in the range 0x0800 - 0x08FF.
Following the policies outlined in [IANA], TLV types in this range Following the policies outlined in [IANA], TLV types in this range
are allocated through an IETF Consensus action. are allocated through an IETF Consensus action.
Initial values for this range are specified in the following table: Initial values for this range are specified in the following table:
TLV Type TLV Type
-------------------------------------- ---------- -------------------------------------- ----------
Explicite Route TLV 0x0800 Explicit Route TLV 0x0800
Ipv4 Prefix ER-Hop TLV 0x0801 Ipv4 Prefix ER-Hop TLV 0x0801
Ipv6 Prefix ER-Hop TLV 0x0802 Ipv6 Prefix ER-Hop TLV 0x0802
Autonomous System Number ER-Hop TLV 0x0803 Autonomous System Number ER-Hop TLV 0x0803
LSP-ID ER-Hop TLV 0x0804 LSP-ID ER-Hop TLV 0x0804
Traffic Parameters TLV 0x0810 Traffic Parameters TLV 0x0810
Preemption TLV 0x0820 Preemption TLV 0x0820
LSPID TLV 0x0821 LSPID TLV 0x0821
Resource Class TLV 0x0822 Resource Class TLV 0x0822
Route Pinning TLV 0x0823 Route Pinning TLV 0x0823
5.2 FEC Type Name Space 5.2 FEC Type Name Space
RFC 3036 defines the FEC Type name space. Further, RFC 3036 has RFC 3036 defines the FEC Type name space. Further, RFC 3036 has
assigned values 0x00 through 0x03. FEC types 0 through 127 are assigned values 0x00 through 0x03. FEC types 0 through 127 are
available for assignment through IETF consensus action. This available for assignment through IETF consensus action. This
specification makes the following additional assignment, using specification makes the following additional assignment, using the
the policies outlined in [IANA]: policies outlined in [IANA]:
FEC Element Type FEC Element Type
-------------------------------------- ---------- -------------------------------------- ----------
CR-LSP FEC Element 0x04 CR-LSP FEC Element 0x04
5.3 Status Code Space 5.3 Status Code Space
RFC 3036 defines the Status Code name space. This document further RFC 3036 defines the Status Code name space. This document further
subdivides the range of RFC 3036 from that TLV space for TLVs subdivides the range of RFC 3036 from that TLV space for TLVs
associated with the CR-LDP in the range 0x04000000 - 0x040000FF. associated with the CR-LDP in the range 0x04000000 - 0x040000FF.
Following the policies outlined in [IANA], TLV types in this range Following the policies outlined in [IANA], TLV types in this range
are allocated through an IETF Consensus action. are allocated through an IETF Consensus action.
Initial values for this range are specified in the following table: Initial values for this range are specified in the following table:
Status Code Type Status Code Type
-------------------------------------- ---------- -------------------------------------- ----------
Bad Explicit Routing TLV Error 0x04000001
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 27 Bad Explicit Routing TLV Error 0x04000001
Bad Strict Node Error 0x04000002 Bad Strict Node Error 0x04000002
Bad Loose Node Error 0x04000003 Bad Loose Node Error 0x04000003
Bad Initial ER-Hop Error 0x04000004 Bad Initial ER-Hop Error 0x04000004
Resource Unavailable 0x04000005 Resource Unavailable 0x04000005
Traffic Parameters Unavailable 0x04000006 Traffic Parameters Unavailable 0x04000006
LSP Preempted 0x04000007 LSP Preempted 0x04000007
Modify Request Not Supported 0x04000008 Modify Request Not Supported 0x04000008
6. Security 6. Security Considerations
CR-LDP inherits the same security mechanism described in Section 4.0 CR-LDP inherits the same security mechanism described in Section 4.0
of [1] to protect against the introduction of spoofed TCP segments of [1] to protect against the introduction of spoofed TCP segments
into LDP session connection streams. into LDP session connection streams.
7. Acknowledgments 7. Acknowledgments
The messages used to signal the CR-LSP setup are based on the work The messages used to signal the CR-LSP setup are based on the work
done by the [1] team. done by the LDP [1] design team.
The list of authors provided with this document is a reduction of the
original list. Currently listed authors wish to acknowledge that a
substantial amount was also contributed to this work by:
Osama Aboul-Magd, Peter Ashwood-Smith, Joel Halpern,
Fiffi Hellstrand, Kenneth Sundell and Pasi Vaananen.
The authors would also like to acknowledge the careful review and The authors would also like to acknowledge the careful review and
comments of Ken Hayward, Greg Wright, Geetha Brown, Brian Williams, comments of Ken Hayward, Greg Wright, Geetha Brown, Brian Williams,
Paul Beaubien, Matthew Yuen, Liam Casey, Ankur Anand, Adrian Farrel. Paul Beaubien, Matthew Yuen, Liam Casey, Ankur Anand and Adrian
Farrel.
8. Intellectual Property Consideration 8. Intellectual Property Consideration
The IETF has been notified of intellectual property rights claimed The IETF has been notified of intellectual property rights claimed in
in regard to some or all of the specification contained in this regard to some or all of the specification contained in this
document. For more information consult the online list of claimed document. For more information consult the online list of claimed
rights. rights.
9. References 9. References
1 Andersson et. al., "Label Distribution Protocol Specification" [1] Andersson, L., Doolan, P., Feldman, N., Fredette, A. and B.
RFC 3036, January 2001. Thomas, "Label Distribution Protocol Specification", RFC 3036,
January 2001.
2 Rosen et. al., "Multiprotocol Label Switching Architecture",
RFC 3031, January 2001.
3 Awduche et. al., "Requirements for Traffic Engineering Over
MPLS", RFC 2702, September 1999.
4 Gleeson, et. al., "A Framework for IP Based Virtual Private
Networks", RFC 2764, February 2000.
5 B. Jamoussi, et. al., "Applicability Statement for CR-LDP", work
in progress, (draft-ietf-mpls-crldp-applic-01), June 2000.
6 S. Bradner, "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119, March 1997.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 28
7 L. Wu, et. al., "LDP State Machine", work in progress,
(draft-ietf-mpls-ldp-state-03), January 2000.
8 J. Ash, et. al., "LSP Modification Using CR-LDP", work in
progress, (draft-ietf-mpls-crlsp-modify-02), October 2000.
10. Author's Addresses
Osama S. Aboul-Magd Loa Andersson
Nortel Networks Utfors Bredband AB
P O Box 3511 Station C Rasundavagen 12 169 29
Ottawa, ON K1Y 4H7 Solna
Canada
Phone: +1 613 763-5827 Tel: +46 8 5270 50 38
Osama@nortelnetworks.com loa.andersson@utfors.se
Peter Ashwood-Smith Ross Callon
Nortel Networks Juniper Networks
P O Box 3511 Station C 1194 North Mathilda Avenue,
Ottawa, ON K1Y 4H7 Sunnyvale, CA 94089
Canada 978-692-6724
Phone: +1 613 763-4534 rcallon@juniper.net
Petera@nortelnetworks.com
Ram Dantu Paul Doolan
Cisco Systems Ennovate Networks
17919 Waterview Parkway 330 Codman Hill Rd
Dallas, 75252 Marlborough MA 01719
+1 469 255 0716 Phone: 978-263-2002
rdantu@cisco.com Pdoolan@ennovatenetworks.com
Nancy Feldman Andre Fredette
IBM Research PhotonEx Corporation
30 Saw Mill River Road 135 South Road
Hawthorne, NY 10532 Bedford, MA 01730
Phone: 914-784-3254 email: fredette@photonex.com
Nkf@us.ibm.com phone: 781-275-8500
Eric Gray Joel M. Halpern [2] Rosen, E., Viswanathan, A. and R. Callon, "Multiprotocol Label
600 Federal Drive Longitude Systems, Inc. Switching Architecture", RFC 3031, January 2001.
Andover, MA 01810 1319 Shepard Road
Phone: (978) 689-1610 Sterling, VA 20164
eric.gray@sandburst.com 703-433-0808 x207
joel@longsys.com
Juha Heinanen Fiffi Hellstrand [3] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M. and J. McManus,
Telia Finland, Inc. Nortel Networks "Requirements for Traffic Engineering Over MPLS", RFC 2702,
Myyrmaentie 2 S:t Eriksgatan 115 September 1999.
01600 VANTAA PO Box 6701, 113 85 Stockholm
Finland Sweden
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 29 [4] Gleeson, B., Lin, A., Heinanen, Armitage, G. and A. Malis, "A
Tel: +358 41 500 4808 +46705593687 Framework for IP Based Virtual Private Networks", RFC 2764,
Jh@telia.fi fiffi@nortelnetworks.com February 2000.
Bilel Jamoussi Timothy E. Kilty [5] Ash, J., Girish, M., Gray, E., Jamoussi, B. and G. Wright,
Nortel Networks Corp. Newbridge Networks, Inc. "Applicability Statement for CR-LDP", RFC 3213, January 2002.
600 Technology Park Drive 5 Corporate Drive
Billerica, MA 01821 Andover, MA 01810
USA USA
Phone: +1 978 288-4506 phone: 978 691-4656
Jamoussi@nortelnetworks.com tkilty@northchurch.net
Andrew G. Malis Muckai K Girish [6] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Vivace Networks Atoga Systems Levels", BCP 14, RFC 2119, March 1997.
2730 Orchard Parkway 49026 Milmont Drive
San Jose, CA 95134 Fremont, CA 94538
Andy.Malis@vivacenetworks.com E-mail: muckai@atoga.com
Tel: +1 408 383 7223
Fax: +1 408 904 4748
Kenneth Sundell Pasi Vaananen [7] Boscher, C., Cheval, P., Wu, L. and E. Gray, "LDP State Machine",
Nortel Networks Nokia Telecommunications RFC 3215, January 2002.
S:t Eriksgatan 115 3 Burlington Woods Drive,
PO Box 6701 Burlington, MA 01803
113 85 Stockholm Phone: +1-781-238-4981
Tel: +46 8 508 835 00 pasi.vaananen@nokia.com
Fax: +46 8 508 835 01
Ksundell@nortelnetworks.com
Tom Worster Liwen Wu [8] Ash, J., Lee, Y., Ashwood-Smith, P., Jamoussi, B., Fedyk, D.,
Ennovate Networks Cisco Systems Skalecki, D. and L. Li, "LSP Modification Using CR-LDP", RFC
60 Codman Hill Rd 250 Apollo Drive 3214, January 2002.
Boxborough Chelmsford, MA. 01824
MA 01719 Tel: 978-244-3087.
tworster@ennovatenetworks.com liwwu@cisco.com
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 30
Appendix A: CR-LSP Establishment Examples Appendix A: CR-LSP Establishment Examples
A.1 Strict Explicit Route Example A.1 Strict Explicit Route Example
This appendix provides an example for the setup of a strictly routed This appendix provides an example for the setup of a strictly routed
CR-LSP. In this example, a specific node represents each abstract CR-LSP. In this example, a specific node represents each abstract
node. node.
The sample network used here is a four node network with two edge The sample network used here is a four node network with two edge
LSRs and two core LSRs as follows: LSRs and two core LSRs as follows:
abc abc
LSR1------LSR2------LSR3------LSR4 LSR1------LSR2------LSR3------LSR4
LSR1 generates a Label Request Message as described in Section 3.1 LSR1 generates a Label Request Message as described in Section 3.1 of
of this draft and sends it to LSR2. This message includes the CR- this document and sends it to LSR2. This message includes the CR-
TLV. TLV.
A vector of three ER-Hop TLVs <a, b, c> composes the ER-TLV. A vector of three ER-Hop TLVs <a, b, c> composes the ER-TLV. The ER-
The ER-Hop TLVs used in this example are of type 0x0801 (IPv4 Hop TLVs used in this example are of type 0x0801 (IPv4 prefix) with a
prefix) with a prefix length of 32. Hence, each ER-Hop TLV prefix length of 32. Hence, each ER-Hop TLV identifies a specific
identifies a specific node as opposed to a group of nodes. node as opposed to a group of nodes. At LSR2, the following
At LSR2, the following processing of the ER-TLV per Section 4.8.1 of processing of the ER-TLV per Section 4.8.1 of this document takes
this draft takes place: place:
1. The node LSR2 is part of the abstract node described by the 1. The node LSR2 is part of the abstract node described by the
first hop <a>. Therefore, the first step passes the test. Go first hop <a>. Therefore, the first step passes the test. Go
to step 2. to step 2.
2. There is a second ER-Hop, <b>. Go to step 3. 2. There is a second ER-Hop, <b>. Go to step 3.
3. LSR2 is not part of the abstract node described by the 3. LSR2 is not part of the abstract node described by the second
second ER-Hop <b>. Go to Step 4. ER-Hop <b>. Go to Step 4.
4. LSR2 determines that it is topologically adjacent to the 4. LSR2 determines that it is topologically adjacent to the
abstract node described by the second ER-Hop <b>. LSR2 selects abstract node described by the second ER-Hop <b>. LSR2 selects
a next hop (LSR3) which is the abstract node. LSR2 deletes the a next hop (LSR3) which is the abstract node. LSR2 deletes the
first ER-Hop <a> from the ER-TLV, which now becomes <b, c>. first ER-Hop <a> from the ER-TLV, which now becomes <b, c>.
Processing continues with Section 4.8.2. Processing continues with Section 4.8.2.
At LSR2, the following processing of Section 4.8.2 takes place: At LSR2, the following processing of Section 4.8.2 takes place:
Executing algorithm 4.8.1 did not result in the removal of the ER- Executing algorithm 4.8.1 did not result in the removal of the ER-
TLV. TLV.
Also, LSR2 is not a member of the abstract node described by the Also, LSR2 is not a member of the abstract node described by the
first ER-Hop <b>. first ER-Hop <b>.
Finally, the first ER-Hop <b> is a strict hop. Finally, the first ER-Hop <b> is a strict hop.
Therefore, processing section 4.8.2 does not result in the insertion Therefore, processing section 4.8.2 does not result in the insertion
of new ER-Hops. The selection of the next hop has been already done of new ER-Hops. The selection of the next hop has been already done
is step 4 of Section 4.8.1 and the processing of the ER-TLV is is step 4 of Section 4.8.1 and the processing of the ER-TLV is
completed at LSR2. In this case, the Label Request Message including
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 31
completed at LSR2. In this case, the Label Request Message including
the ER-TLV <b, c> is progressed by LSR2 to LSR3. the ER-TLV <b, c> is progressed by LSR2 to LSR3.
At LSR3, a similar processing to the ER-TLV takes place except that At LSR3, a similar processing to the ER-TLV takes place except that
the incoming ER-TLV = <b, c> and the outgoing ER-TLV is <c>. the incoming ER-TLV = <b, c> and the outgoing ER-TLV is <c>.
At LSR4, the following processing of section 4.8.1 takes place: At LSR4, the following processing of section 4.8.1 takes place:
1. The node LSR4 is part of the abstract node described by the 1. The node LSR4 is part of the abstract node described by the
first hop <c>. Therefore, the first step passes the test. Go to first hop <c>. Therefore, the first step passes the test. Go
step 2. to step 2.
2. There is no second ER-Hop, this indicates the end of the CR- 2. There is no second ER-Hop, this indicates the end of the CR-
LSP. The ER-TLV is removed from the Label Request Message. LSP. The ER-TLV is removed from the Label Request Message.
Processing continues with Section 4.8.2. Processing continues with Section 4.8.2.
At LSR4, the following processing of Section 4.8.2 takes place: At LSR4, the following processing of Section 4.8.2 takes place:
Executing algorithm 4.8.1 resulted in the removal of the ER-TLV. Executing algorithm 4.8.1 resulted in the removal of the ER-TLV. LSR4
LSR4 does not add a new ER-TLV. does not add a new ER-TLV.
Therefore, processing section 4.8.2 does not result in the insertion Therefore, processing section 4.8.2 does not result in the insertion
of new ER-Hops. This indicates the end of the CR-LSP and the of new ER-Hops. This indicates the end of the CR-LSP and the
processing of the ER-TLV is completed at LSR4. processing of the ER-TLV is completed at LSR4.
At LSR4, processing of Section 3.2 is invoked. The first condition At LSR4, processing of Section 3.2 is invoked. The first condition
is satisfied (LSR4 is the egress end of the CR-LSP and upstream is satisfied (LSR4 is the egress end of the CR-LSP and upstream
mapping has been requested). Therefore, a Label Mapping Message is mapping has been requested). Therefore, a Label Mapping Message is
generated by LSR4 and sent to LSR3. generated by LSR4 and sent to LSR3.
At LSR3, the processing of Section 3.2 is invoked. The second At LSR3, the processing of Section 3.2 is invoked. The second
condition is satisfied (LSR3 received a mapping from its downstream condition is satisfied (LSR3 received a mapping from its downstream
next hop LSR4 for a CR-LSP for which an upstream request is still next hop LSR4 for a CR-LSP for which an upstream request is still
pending). Therefore, a Label Mapping Message is generated by LSR3 pending). Therefore, a Label Mapping Message is generated by LSR3
and sent to LSR2. and sent to LSR2.
At LSR2, a similar processing to LSR 3 takes place and a Label At LSR2, a similar processing to LSR 3 takes place and a Label
Mapping Message is sent back to LSR1, which completes the end-to-end Mapping Message is sent back to LSR1, which completes the end-to-end
CR-LSP setup. CR-LSP setup.
A.2 Node Groups and Specific Nodes Example A.2 Node Groups and Specific Nodes Example
A request at ingress LSR to setup a CR-LSP might originate from a A request at ingress LSR to setup a CR-LSP might originate from a
management system or an application, the details are implementation management system or an application, the details are implementation
specific. specific.
The ingress LSR uses information provided by the management system The ingress LSR uses information provided by the management system or
or the application and possibly also information from the routing the application and possibly also information from the routing
database to calculate the explicit route and to create the Label database to calculate the explicit route and to create the Label
Request Message. Request Message.
The Label request message carries together with other necessary The Label request message carries together with other necessary
information an ER-TLV defining the explicitly routed path. In our information an ER-TLV defining the explicitly routed path. In our
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 32
example the list of hops in the ER-Hop TLV is supposed to contain an example the list of hops in the ER-Hop TLV is supposed to contain an
abstract node representing a group of nodes, an abstract node abstract node representing a group of nodes, an abstract node
representing a specific node, another abstract node representing a representing a specific node, another abstract node representing a
group of nodes, and an abstract node representing a specific egress group of nodes, and an abstract node representing a specific egress
point. point.
In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B} In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B}
The ER-TLV contains four ER-Hop TLVs: The ER-TLV contains four ER-Hop TLVs:
1. An ER-Hop TLV that specifies a group of LSR valid for the 1. An ER-Hop TLV that specifies a group of LSR valid for the first
first abstract node representing a group of nodes (Group 1). abstract node representing a group of nodes (Group 1).
2. An ER-Hop TLV that indicates the specific node (Node A). 2. An ER-Hop TLV that indicates the specific node (Node A).
3. An ER-Hop TLV that specifies a group of LSRs valid for the 3. An ER-Hop TLV that specifies a group of LSRs valid for the
second abstract node representing a group of nodes (Group 2). second abstract node representing a group of nodes (Group 2).
4. An ER-Hop TLV that indicates the specific egress point for 4. An ER-Hop TLV that indicates the specific egress point for the
the CR-LSP (Node B). CR-LSP (Node B).
All the ER-Hop TLVs are strictly routed nodes. All the ER-Hop TLVs are strictly routed nodes.
The setup procedure for this CR-LSP works as follows: The setup procedure for this CR-LSP works as follows:
1. The ingress node sends the Label Request Message to a node 1. The ingress node sends the Label Request Message to a node
that is a member the group of nodes indicated in the first ER- that is a member the group of nodes indicated in the first ER-
Hop TLV, following normal routing for the specific node (A). Hop TLV, following normal routing for the specific node (A).
2. The node that receives the message identifies itself as part 2. The node that receives the message identifies itself as part
of the group indicated in the first ER-Hop TLV, and that it is of the group indicated in the first ER-Hop TLV, and that it is
not the specific node (A) in the second. Further it realizes not the specific node (A) in the second. Further it realizes
that the specific node (A) is not one of its next hops. that the specific node (A) is not one of its next hops.
3. It keeps the ER-Hop TLVs intact and sends a Label Request 3. It keeps the ER-Hop TLVs intact and sends a Label Request
Message to another node that is part of the group indicated in Message to another node that is part of the group indicated in
the first ER-Hop TLV (Group 1), following normal routing for the first ER-Hop TLV (Group 1), following normal routing for
the specific node (A). the specific node (A).
4. The node that receives the message identifies itself as part 4. The node that receives the message identifies itself as part
of the group indicated in the first ER-Hop TLV, and that it is of the group indicated in the first ER-Hop TLV, and that it is
not the specific node (A) in the second ER-Hop TLV. Further it not the specific node (A) in the second ER-Hop TLV. Further
realizes that the specific node (A) is one of its next hops. it realizes that the specific node (A) is one of its next
hops.
5. It removes the first ER-Hop TLVs and sends a Label Request 5. It removes the first ER-Hop TLVs and sends a Label Request
Message to the specific node (A). Message to the specific node (A).
6. The specific node (A) recognizes itself in the first ER-Hop 6. The specific node (A) recognizes itself in the first ER-Hop
TLV. Removes the specific ER-Hop TLV. TLV. Removes the specific ER-Hop TLV.
7. It sends a Label Request Message to a node that is a member 7. It sends a Label Request Message to a node that is a member of
of the group (Group 2) indicated in the ER-Hop TLV. the group (Group 2) indicated in the ER-Hop TLV.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 33 8. The node that receives the message identifies itself as part
8. The node that receives the message identifies itself as part of the group indicated in the first ER-Hop TLV, further it
of the group indicated in the first ER-Hop TLV, further it realizes that the specific egress node (B) is one of its next
realizes that the specific egress node (B) is one of its next hops.
hops.
9. It sends a Label Request Message to the specific egress node 9. It sends a Label Request Message to the specific egress node
(B). (B).
10. The specific egress node (B) recognizes itself as the 10. The specific egress node (B) recognizes itself as the egress
egress for the CR-LSP, it returns a Label Mapping Message, that for the CR-LSP, it returns a Label Mapping Message, that will
will traverse the same path as the Label Request Message in the traverse the same path as the Label Request Message in the
opposite direction. opposite direction.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 34 Appendix B. QoS Service Examples
Appendix B. QoS Service Examples
B.1 Service Examples B.1 Service Examples
Construction of an end-to-end service is the result of the rules Construction of an end-to-end service is the result of the rules
enforced at the edge and the treatment that packets receive at the enforced at the edge and the treatment that packets receive at the
network nodes. The rules define the traffic conditioning actions network nodes. The rules define the traffic conditioning actions
that are implemented at the edge and they include policing with that are implemented at the edge and they include policing with pass,
pass, mark, and drop capabilities. The edge rules are expected tobe mark, and drop capabilities. The edge rules are expected to be
defined by the mutual agreements between the service providers and defined by the mutual agreements between the service providers and
their customers and they will constitute an essential part of the their customers and they will constitute an essential part of the
SLA. Therefore edge rules are not included in the signaling SLA. Therefore edge rules are not included in the signaling
protocol. protocol.
Packet treatment at a network node is usually referred to as the Packet treatment at a network node is usually referred to as the
local behavior. Local behavior could be specified in many ways. One local behavior. Local behavior could be specified in many ways. One
example for local behavior specification is the service frequency example for local behavior specification is the service frequency
introduced in section 4.3.2.1, together with the resource introduced in section 4.3.2.1, together with the resource reservation
reservation rules implemented at the nodes. rules implemented at the nodes.
Edge rules and local behaviors can be viewed as the main building Edge rules and local behaviors can be viewed as the main building
blocks for the end-to-end service construction. The following table blocks for the end-to-end service construction. The following table
illustrates the applicability of the building block approach for illustrates the applicability of the building block approach for
constructing different services including those defined for ATM. constructing different services including those defined for ATM.
Service PDR PBS CDR CBS EBS Service Conditioning Service PDR PBS CDR CBS EBS Service Conditioning
Examples Frequency Action Examples Frequency Action
DS S S =PDR =PBS 0 Frequent drop>PDR DS S S =PDR =PBS 0 Frequent drop>PDR
TS S S S S 0 Unspecified drop>PDR,PBS TS S S S S 0 Unspecified drop>PDR,PBS
mark>CDR,CBS mark>CDR,CBS
skipping to change at line 1772 skipping to change at page 37, line 38
ATM-VBR.3(nrt) PCR CDVT SCR MBS 0 Unspecified drop>PCR ATM-VBR.3(nrt) PCR CDVT SCR MBS 0 Unspecified drop>PCR
mark>SCR,MBS mark>SCR,MBS
ATM-UBR PCR CDVT - - 0 Unspecified drop>PCR ATM-UBR PCR CDVT - - 0 Unspecified drop>PCR
ATM-GFR.1 PCR CDVT MCR MBS 0 Unspecified drop>PCR ATM-GFR.1 PCR CDVT MCR MBS 0 Unspecified drop>PCR
ATM-GFR.2 PCR CDVT MCR MBS 0 Unspecified drop>PCR ATM-GFR.2 PCR CDVT MCR MBS 0 Unspecified drop>PCR
mark>MCR,MFS mark>MCR,MFS
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 35
int-serv-CL p m r b 0 Frequent drop>p int-serv-CL p m r b 0 Frequent drop>p
drop>r,b drop>r,b
S= User specified S= User specified
In the above table, the DS refers to a delay sensitive service where In the above table, the DS refers to a delay sensitive service where
the network commits to deliver with high probability user datagrams the network commits to deliver with high probability user datagrams
at a rate of PDR with minimum delay and delay requirements. at a rate of PDR with minimum delay and delay requirements. Datagrams
Datagrams in excess of PDR will be discarded. in excess of PDR will be discarded.
The TS refers to a generic throughput sensitive service where the The TS refers to a generic throughput sensitive service where the
network commits to deliver with high probability user datagrams at a network commits to deliver with high probability user datagrams at a
rate of at least CDR. The user may transmit at a rate higher than rate of at least CDR. The user may transmit at a rate higher than
CDR but datagrams in excess of CDR would have a lower probability of CDR but datagrams in excess of CDR would have a lower probability of
being delivered. being delivered.
The BE is the best effort service and it implies that there are no The BE is the best effort service and it implies that there are no
expected service guarantees from the network. expected service guarantees from the network.
B.2 Establishing CR-LSP Supporting Real-Time Applications B.2 Establishing CR-LSP Supporting Real-Time Applications
In this scenario the customer needs to establish an LSP for In this scenario the customer needs to establish an LSP for
supporting real-time applications such as voice and video. The supporting real-time applications such as voice and video. The
Delay-sensitive (DS) service is requested in this case. Delay-sensitive (DS) service is requested in this case.
The first step is the specification of the traffic parameters in the The first step is the specification of the traffic parameters in the
signaling message. The two parameters of interest to the DS service signaling message. The two parameters of interest to the DS service
are the PDR and the PBS and the user based on his requirements are the PDR and the PBS and the user based on his requirements
specifies their values. Since all the traffic parameters are specifies their values. Since all the traffic parameters are
included in the signaling message, appropriate values must be included in the signaling message, appropriate values must be
assigned to all of them. For DS service, the CDR and the CBS values assigned to all of them. For DS service, the CDR and the CBS values
are set equal to the PDR and the PBS respectively. An indication of are set equal to the PDR and the PBS respectively. An indication of
whether the parameter values are subject to negotiation is flagged. whether the parameter values are subject to negotiation is flagged.
The transport characteristics of the DS service require Frequent The transport characteristics of the DS service require Frequent
frequency to be requested to reflect the real-time delay frequency to be requested to reflect the real-time delay requirements
requirements of the service. of the service.
In addition to the transport characteristics, both the network In addition to the transport characteristics, both the network
provider and the customer need to agree on the actions enforced at provider and the customer need to agree on the actions enforced at
the edge. The specification of those actions is expected to be a the edge. The specification of those actions is expected to be a
part of the service level agreement (SLA) negotiation and is not part of the service level agreement (SLA) negotiation and is not
included in the signaling protocol. For DS service, the edge action included in the signaling protocol. For DS service, the edge action
is to drop packets that exceed the PDR and the PBS specifications. is to drop packets that exceed the PDR and the PBS specifications.
The signaling message will be sent in the direction of the ER path The signaling message will be sent in the direction of the ER path
and the LSP is established following the normal LDP procedures. Each and the LSP is established following the normal LDP procedures. Each
LSR applies its admission control rules. If sufficient resources are LSR applies its admission control rules. If sufficient resources are
not available and the parameter values are subject to negotiation, not available and the parameter values are subject to negotiation,
then the LSR could negotiate down the PDR, the PBS, or both. then the LSR could negotiate down the PDR, the PBS, or both.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 36
The new parameter values are echoed back in the Label Mapping The new parameter values are echoed back in the Label Mapping
Message. LSRs might need to re-adjust their resource reservations Message. LSRs might need to re-adjust their resource reservations
based on the new traffic parameter values. based on the new traffic parameter values.
B.3 Establishing CR-LSP Supporting Delay Insensitive Applications B.3 Establishing CR-LSP Supporting Delay Insensitive Applications
In this example we assume that a throughput sensitive (TS) service In this example we assume that a throughput sensitive (TS) service is
is requested. For resource allocation the user assigns values for requested. For resource allocation the user assigns values for PDR,
PDR, PBS, CDR, and CBS. The negotiation flag is set if the traffic PBS, CDR, and CBS. The negotiation flag is set if the traffic
parameters are subject to negotiation. parameters are subject to negotiation.
Since the service is delay insensitive by definition, the Since the service is delay insensitive by definition, the Unspecified
Unspecified frequency is signaled to indicate that the service frequency is signaled to indicate that the service frequency is not
frequency is not an issue. an issue.
Similar to the previous example, the edge actions are not subject Similar to the previous example, the edge actions are not subject for
for signaling and are specified in the service level agreement signaling and are specified in the service level agreement between
between the user and the network provider. the user and the network provider.
For TS service, the edge rules might include marking to indicate For TS service, the edge rules might include marking to indicate high
high discard precedence values for all packets that exceed CDR and discard precedence values for all packets that exceed CDR and the
the CBS. The edge rules will also include dropping of packets that CBS. The edge rules will also include dropping of packets that
conform to neither PDR nor PBS. conform to neither PDR nor PBS.
Each LSR of the LSP is expected to run its admission control rules Each LSR of the LSP is expected to run its admission control rules
and negotiate traffic parameters down if sufficient resources do not and negotiate traffic parameters down if sufficient resources do not
exist. The new parameter values are echoed back in the Label Mapping exist. The new parameter values are echoed back in the Label Mapping
Message. LSRs might need to re-adjust their resources based on the Message. LSRs might need to re-adjust their resources based on the
new traffic parameter values. new traffic parameter values.
Jamoussi, et. al. draft-ietf-mpls-crldp-06.txt 37 10. Author's Addresses
Loa Andersson
Utfors Bredband AB
Rasundavagen 12 169 29
Solna
Phone: +46 8 5270 50 38
EMail: loa.andersson@utfors.se
Ross Callon
Juniper Networks
1194 North Mathilda Avenue,
Sunnyvale, CA 94089
Phone: 978-692-6724
EMail: rcallon@juniper.net
Ram Dantu
Netrake Corporation
3000 Technology Drive, #100
Plano Texas, 75024
Phone: 214 291 1111
EMail: rdantu@netrake.com
Paul Doolan
On The Beach Consulting Corp
34 Mill Pond Circle
Milford MA 01757
Phone 617 513 852
EMail: pdoolan@acm.org
Nancy Feldman
IBM Research
30 Saw Mill River Road
Hawthorne, NY 10532
Phone: 914-784-3254
EMail: Nkf@us.ibm.com
Andre Fredette
ANF Consulting
62 Duck Pond Dr.
Groton, MA 01450
EMail: afredette@charter.net
Eric Gray
600 Federal Drive
Andover, MA 01810
Phone: (978) 689-1610
EMail: eric.gray@sandburst.com
Juha Heinanen
Song Networks, Inc.
Hallituskatu 16
33200 Tampere, Finland
EMail: jh@song.fi
Bilel Jamoussi
Nortel Networks
600 Technology Park Drive
Billerica, MA 01821
USA
Phone: +1 978 288-4506
Mail: Jamoussi@nortelnetworks.com
Timothy E. Kilty
Island Consulting
Phone: (978) 462 7091
EMail: tim-kilty@mediaone.net
Andrew G. Malis
Vivace Networks
2730 Orchard Parkway
San Jose, CA 95134
Phone: +1 408 383 7223
EMail: Andy.Malis@vivacenetworks.com
Muckai K Girish
Atoga Systems
49026 Milmont Drive
Fremont, CA 94538
EMail: muckai@atoga.com
Tom Worster
Phone: 617 247 2624
EMail: fsb@thefsb.org
Liwen Wu
Cisco Systems
250 Apollo Drive
Chelmsford, MA. 01824
Phone: 978-244-3087
EMail: liwwu@cisco.com
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