draft-ietf-teas-p2mp-loose-path-reopt-05.txt   draft-ietf-teas-p2mp-loose-path-reopt-06.txt 
TEAS Working Group T. Saad, Ed. TEAS Working Group T. Saad, Ed.
Internet-Draft R. Gandhi, Ed. Internet-Draft R. Gandhi, Ed.
Intended status: Standards Track Z. Ali Intended status: Standards Track Z. Ali
Expires: September 12, 2016 Cisco Systems, Inc. Expires: March 8, 2017 Cisco Systems, Inc.
R. Venator R. Venator
Defense Information Systems Agency Defense Information Systems Agency
Y. Kamite Y. Kamite
NTT Communications Corporation NTT Communications Corporation
March 11, 2016 September 4, 2016
RSVP Extensions For Re-optimization of Loosely Routed RSVP Extensions For Re-optimization of Loosely Routed
Point-to-Multipoint Traffic Engineering Label Switched Paths (LSPs) Point-to-Multipoint Traffic Engineering Label Switched Paths (LSPs)
draft-ietf-teas-p2mp-loose-path-reopt-05 draft-ietf-teas-p2mp-loose-path-reopt-06
Abstract Abstract
For a Traffic Engineered (TE) Point-to-Multipoint (P2MP) Label Re-optimization of a Point-to-Multipoint (P2MP) Traffic Engineered
Switched Path (LSP), it is preferable in some cases to re-evaluate (TE) Label Switched Path (LSP) may be triggered based on the need to
and re-optimize the entire P2MP-TE LSP by re-signaling all its re-optimize an individual source-to-leaf (S2L) sub-LSP or a set of
Source-to-Leaf (S2L) sub-LSP(s). Existing mechanisms, a mechanism S2L sub-LSPs, both using Sub-Group-Based Re-optimization method, or
for an ingress Label Switched Router (LSR) to trigger a new path the entire P2MP-TE LSP tree using the Make-Before-Break (MBB) method.
re-evaluation request and a mechanism for a mid-point LSR to notify Mechanisms that facilitate path re-optimization of loosely routed
an availability of a preferred path, operate on an individual or a Point-to-Point (P2P) TE LSPs include a method for the ingress node to
sub-group of S2L sub-LSP(s) basis only. trigger a new path re-evaluation request and a method for the mid-
point node to notify availability of a preferred path. This document
discusses the application of these mechanisms to the re-optimization
of loosely routed P2MP-TE LSPs, identifies issues in doing so and
proposes procedures to address them.
This document defines Resource Reservation Protocol (RSVP) signaling This document defines Resource Reservation Protocol (RSVP) signaling
extensions to allow an ingress node of a P2MP-TE LSP to request the extensions to allow the ingress node of a loosely routed P2MP-TE LSP
re-evaluation of the entire LSP tree containing one or more S2L to request the re-evaluation of the entire LSP tree, and a mid-point
sub-LSPs whose paths are loose (or abstract) hop expanded, and for a node to notify to the ingress node that a preferable tree exists for
mid-point LSR to notify to the ingress node that a preferable tree the entire P2MP-TE LSP. For re-optimizing a group of S2L sub-LSPs in
exists for the entire P2MP-TE LSP. For re-optimizing a group of S2L a tree using the Sub-Group-Based Re-optimization method, an S2L sub-
sub-LSP(s) in a tree, an S2L sub-LSP descriptor list can be used to LSP descriptor list can be used to signal one or more S2L sub-LSPs in
signal one or more S2L sub-LSPs in an RSVP message. This document an RSVP message. This RSVP message may need to be fragmented when
defines fragment identifier for the S2L sub-LSP descriptor list when large number of S2L sub-LSPs are added to the descriptor list. This
the RSVP message needs to be fragmented due to large number of S2L document introduces the notion of a fragment identifier to help
sub-LSPs in the message when performing sub-group based recipient nodes unambiguously reconstruct the fragmented S2L sub-LSP
re-optimization. descriptor list.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
skipping to change at page 3, line 16 skipping to change at page 3, line 16
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Loosely Routed Inter-domain P2MP-TE LSP Tree . . . . . . . 5 1.1. Loosely Routed Inter-domain P2MP-TE LSP Tree . . . . . . . 5
1.2. Existing Mechanism For Tree-Based P2MP-TE LSP 1.2. Existing Mechanism For Tree-Based P2MP-TE LSP
Re-optimization . . . . . . . . . . . . . . . . . . . . . 5 Re-optimization . . . . . . . . . . . . . . . . . . . . . 5
1.3. Existing Mechanism For Sub-Group-Based P2MP-TE LSP 1.3. Existing Mechanism For Sub-Group-Based P2MP-TE LSP
Re-optimization . . . . . . . . . . . . . . . . . . . . . 6 Re-optimization . . . . . . . . . . . . . . . . . . . . . 6
2. Conventions Used in This Document . . . . . . . . . . . . . . 7 2. Conventions Used in This Document . . . . . . . . . . . . . . 7
2.1. Key Word Definitions . . . . . . . . . . . . . . . . . . . 7 2.1. Key Word Definitions . . . . . . . . . . . . . . . . . . . 7
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 7 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 7
2.3. Nomenclatures . . . . . . . . . . . . . . . . . . . . . . 8 2.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 8
3. Signaling Procedure For Loosely Routed P2MP-TE LSP 3. Signaling Procedure For Loosely Routed P2MP-TE LSP
Re-optimization . . . . . . . . . . . . . . . . . . . . . . . 8 Re-optimization . . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Tree-Based Re-optimization . . . . . . . . . . . . . . . . 8 3.1. Tree-Based Re-optimization . . . . . . . . . . . . . . . . 8
3.2. Sub-Group-Based Re-optimization Using Fragment 3.2. Sub-Group-Based Re-optimization Using Fragment
Identifier . . . . . . . . . . . . . . . . . . . . . . . . 9 Identifier . . . . . . . . . . . . . . . . . . . . . . . . 9
4. Message and Object Definitions . . . . . . . . . . . . . . . . 10 4. Message and Object Definitions . . . . . . . . . . . . . . . . 10
4.1. P2MP-TE Tree Re-evaluation Request Flag . . . . . . . . . 10 4.1. P2MP-TE Tree Re-evaluation Request Flag . . . . . . . . . 10
4.2. Preferable P2MP-TE Tree Exists Path Error Sub-code . . . . 10 4.2. Preferable P2MP-TE Tree Exists Path Error Sub-code . . . . 10
4.3. Fragment Identifier For S2L sub-LSP Descriptor . . . . . . 11 4.3. Fragment Identifier For S2L sub-LSP Descriptor . . . . . . 11
5. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 12 5. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 12
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
6.1. P2MP-TE Tree Re-evaluation Request Flag . . . . . . . . . 12 6.1. P2MP-TE Tree Re-evaluation Request Flag . . . . . . . . . 12
6.2. Preferable P2MP-TE Tree Exists Path Error Sub-code . . . . 12 6.2. Preferable P2MP-TE Tree Exists Path Error Sub-code . . . . 13
6.3. Fragment Identifier For S2L sub-LSP Descriptor . . . . . . 13 6.3. Fragment Identifier For S2L sub-LSP Descriptor . . . . . . 13
7. Security Considerations . . . . . . . . . . . . . . . . . . . 14 7. Security Considerations . . . . . . . . . . . . . . . . . . . 14
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.1. Normative References . . . . . . . . . . . . . . . . . . . 15 8.1. Normative References . . . . . . . . . . . . . . . . . . . 15
8.2. Informative References . . . . . . . . . . . . . . . . . . 15 8.2. Informative References . . . . . . . . . . . . . . . . . . 15
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 16 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 16
Author's Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 Author's Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction 1. Introduction
This document defines Resource Reservation Protocol - Traffic This document defines Resource Reservation Protocol - Traffic
Engineering (RSVP-TE) [RFC2205] [RFC3209] signaling extensions for Engineering (RSVP-TE) [RFC2205] [RFC3209] signaling extensions for
re-optimizing loosely routed Point-to-Multipoint (P2MP) Traffic re-optimizing loosely routed Point-to-Multipoint (P2MP) Traffic
Engineered (TE) Label Switched Paths (LSPs) [RFC4875] in an Engineered (TE) Label Switched Paths (LSPs) [RFC4875] in a
Multi-Protocol Label Switching (MPLS) and/or Generalized MPLS (GMPLS) Multi-Protocol Label Switching (MPLS) or Generalized MPLS (GMPLS)
networks. network.
A P2MP-TE LSP is comprised of one or more source-to-leaf (S2L) A P2MP-TE LSP is comprised of one or more source-to-leaf (S2L)
sub-LSPs. A loosely routed P2MP-TE S2L sub-LSP is defined as one sub-LSPs. A loosely routed P2MP-TE S2L sub-LSP is defined as one
whose path does not contain the full explicit route identifying each whose path does not contain the full explicit route identifying each
node along the path to the egress node at the time of its signaling node along the path to the egress node at the time of its signaling
by the ingress node. Such an S2L sub-LSP is signaled with no by the ingress node. Such an S2L sub-LSP is signaled with no
Explicit Route Object (ERO) [RFC3209], or with an ERO that contains Explicit Route Object (ERO) [RFC3209], or with an ERO that contains
at least one loose hop, or with an ERO that contains an abstract node at least one loose hop, or with an ERO that contains an abstract node
that is not a simple abstract node (that is, an abstract node that which identifies more than one node. This is often the case with
identifies more than one node). This is often the case with
inter-domain P2MP-TE LSPs where Path Computation Element (PCE) is not inter-domain P2MP-TE LSPs where Path Computation Element (PCE) is not
used [RFC5440]. used [RFC5440].
As per [RFC4875], an ingress node may re-optimize the entire P2MP-TE As per [RFC4875], an ingress node may re-optimize the entire P2MP-TE
LSP by re-signaling all its S2L sub-LSP(s) or may re-optimize LSP by re-signaling all its S2L sub-LSP(s) or may re-optimize
individual or group of S2L sub-LSP(s) i.e. individual or group of individual or group of S2L sub-LSP(s) i.e. individual or group of
destination(s). destination(s).
[RFC4736] defines RSVP signaling extensions for re-optimizing loosely [RFC4736] defines RSVP signaling extensions for re-optimizing loosely
routed Point-to-Point (P2P) TE LSP(s) as follows: routed Point-to-Point (P2P) TE LSP(s) as follows:
skipping to change at page 4, line 48 skipping to change at page 4, line 47
o An ingress node triggers a path re-evaluation request at all o An ingress node triggers a path re-evaluation request at all
mid-point LSR(s) that expands loose next-hop(s) by setting the "Path mid-point LSR(s) that expands loose next-hop(s) by setting the "Path
Re-evaluation Request" flag (0x20) in SESSION_ATTRIBUTES Object in Re-evaluation Request" flag (0x20) in SESSION_ATTRIBUTES Object in
the Path message. the Path message.
o The ingress node upon receiving this PathErr either solicited or o The ingress node upon receiving this PathErr either solicited or
unsolicited initiates re-optimization of the LSP with a different unsolicited initiates re-optimization of the LSP with a different
LSP-ID. LSP-ID.
Following sections discuss the issues that may arise when using The following sections discuss the issues that may arise when
existing mechanisms defined in [RFC4736] for re-optimizing loosely applying the mechanisms defined in [RFC4736] for re-optimizing
routed P2MP-TE LSPs. loosely routed P2MP-TE LSPs.
1.1. Loosely Routed Inter-domain P2MP-TE LSP Tree 1.1. Loosely Routed Inter-domain P2MP-TE LSP Tree
An example of a loosely routed inter-domain P2MP-TE LSP tree is shown An example of a loosely routed inter-domain P2MP-TE LSP tree is shown
in Figure 1. In this example, the P2MP-TE LSP tree consists of 3 S2L in Figure 1. In this example, the P2MP-TE LSP tree consists of 3 S2L
sub-LSPs, to destinations (i.e. leafs) R10, R11 and R12 from the sub-LSPs, to destinations (i.e. leafs) R10, R11 and R12 from the
ingress node (i.e. source) R1. Nodes R2 and R5 are branch nodes and ingress node (i.e. source) R1. Nodes R2 and R5 are branch nodes and
nodes ABR3, ABR4, ABR7, ABR8 and ABR9 are area border routers. For nodes ABR3, ABR4, ABR7, ABR8 and ABR9 are area border routers. For
the S2L sub-LSP to destination R10, nodes ABR3, ABR7 and R10 are the S2L sub-LSP to destination R10, nodes ABR3, ABR7 and R10 are
defined as loose hops. For the S2L sub-LSP to destination R11, nodes defined as loose hops. For the S2L sub-LSP to destination R11, nodes
skipping to change at page 5, line 37 skipping to change at page 5, line 37
\ \
ABR4---R6 ABR4---R6
\ \
\ \
ABR9---R12 ABR9---R12
Figure 1: An Example of Loosely Routed Inter-domain P2MP-TE LSP Tree Figure 1: An Example of Loosely Routed Inter-domain P2MP-TE LSP Tree
1.2. Existing Mechanism For Tree-Based P2MP-TE LSP Re-optimization 1.2. Existing Mechanism For Tree-Based P2MP-TE LSP Re-optimization
[RFC4736] does not define signaling extensions specific for Mechanisms defined in [RFC4736] can be easily applied to trigger the
re-optimizing entire P2MP-TE LSP tree. Mechanisms defined in re-optimization of individual or group of S2L sub-LSP(s). However,
[RFC4736] can be used for signaling the re-optimization of individual to apply these [RFC4736] mechanisms for triggering the
or group of S2L sub-LSP(s). However, to use [RFC4736] mechanisms for re-optimization of an entire P2MP-TE LSP tree, an ingress node needs
re-optimizing an entire P2MP-TE LSP tree, an ingress node needs to to send path re-evaluation requests on all (typically 100s of) S2L
send the path re-evaluation requests on all (typically 100s of) S2L sub-LSPs and the mid-point LSR needs to send notify PathErrs for all
sub-LSPs and the mid-point LSR to notify PathErrs for all S2L S2L sub-LSPs. Such mechanisms may lead to the following issues:
sub-LSPs. Such mechanisms may lead to the following issues:
o A mid-point LSR that expands loose next-hop(s) may have to o A mid-point LSR that expands loose next-hop(s) may have to
accumulate the received path re-evaluation request(s) for all S2L accumulate the received path re-evaluation request(s) for all S2L
sub-LSPs (e.g. by using a wait timer) and interpret them as a sub-LSPs (e.g. by using a wait timer) and interpret them as a
re-optimization request for the whole P2MP-TE LSP tree. Otherwise, a re-optimization request for the whole P2MP-TE LSP tree. Otherwise, a
mid-point LSR may prematurely notify "Preferable Path Exists" for one mid-point LSR may prematurely notify "Preferable Path Exists" for one
or a sub-set of S2L sub-LSPs. or a sub-set of S2L sub-LSPs.
o Similarly, the ingress node may have to heuristically determine o Similarly, the ingress node may have to heuristically determine
when to perform entire P2MP-TE LSP tree re-optimization versus per when to perform entire P2MP-TE LSP tree re-optimization and when to
S2L sub-LSP re-optimization, for example, to delay re-optimization perform S2L sub-LSP re-optimization. For example, an implementation
long enough to allow all PathErr(s) to be received. Such procedures may choose to delay re-optimization long enough to allow all
may produce undesired results due to timing related issues. PathErr(s) to be received. Such timer-based procedures may produce
undesired results.
o The ingress node that receives (un)solicited PathErr o The ingress node that receives (un)solicited PathErr
notification(s) for individual S2L sub-LSP(s), may prematurely start notification(s) for individual S2L sub-LSP(s), may prematurely start
re-optimizing the sub-set of S2L sub-LSPs. However, as mentioned in re-optimizing the sub-set of S2L sub-LSPs. However, as mentioned in
[RFC4875] Section 14.2, such sub-group based re-optimization [RFC4875] Section 14.2, such sub-group based re-optimization
procedure may result in data duplication that can be avoided if the procedure may result in data duplication that can be avoided if the
entire P2MP-TE LSP tree is re-optimized using a different LSP-ID, entire P2MP-TE LSP tree is re-optimized using a different LSP-ID,
especially if the ingress node eventually receives PathErr especially if the ingress node eventually receives PathErr
notifications for all S2L sub-LSPs of the P2MP-TE LSP tree. notifications for all S2L sub-LSPs of the P2MP-TE LSP tree.
skipping to change at page 6, line 36 skipping to change at page 6, line 36
requirement, this document defines RSVP-TE signaling extensions for requirement, this document defines RSVP-TE signaling extensions for
the ingress node to trigger the re-evaluation of the P2MP LSP tree on the ingress node to trigger the re-evaluation of the P2MP LSP tree on
every hop that has a next-hop defined as a loose or abstract hop for every hop that has a next-hop defined as a loose or abstract hop for
one or more S2L sub-LSP path, and a mid-point LSR to signal to the one or more S2L sub-LSP path, and a mid-point LSR to signal to the
ingress node that a preferable LSP tree exists (compared to the ingress node that a preferable LSP tree exists (compared to the
current path) or that the whole P2MP-TE LSP must be re-optimized current path) or that the whole P2MP-TE LSP must be re-optimized
(because of maintenance required on the TE LSP path). (because of maintenance required on the TE LSP path).
1.3. Existing Mechanism For Sub-Group-Based P2MP-TE LSP Re-optimization 1.3. Existing Mechanism For Sub-Group-Based P2MP-TE LSP Re-optimization
Based on [RFC4875] (Section 14.2 "Sub-Group-Based Re-Optimization"), Applying the procedures discussed in RFC4736 in conjunction with the
an ingress node may trigger path re-evaluation requests using the Sub-Group-Based Re-Optimization procedures ([RFC4875], Section 14.2),
procedures defined in [RFC4736] for a set of S2L sub-LSPs and an ingress node MAY trigger path re-evaluation requests for a set of
combining multiple Path messages using S2L sub-LSP descriptor list. S2L sub-LSPs in a single Path message using S2L sub-LSP descriptor
Similarly, a mid-point LSR may send a PathErr message (with Error list. Similarly, a mid-point LSR may send a PathErr message (with
code 25, sub-code 6) containing a list of S2L sub-LSPs transiting Error code 25, sub-code 6) containing a list of S2L sub-LSPs
through the LSR using an S2L sub-LSP descriptor list to notify the transiting through the LSR using an S2L sub-LSP descriptor list to
ingress node. This method can be used for re-optimizing a sub-group notify the ingress node. This method can be used for re-optimizing a
of S2L sub-LSPs within an LSP tree using the same LSP-ID. This sub-group of S2L sub-LSPs within an LSP tree using the same LSP-ID.
method can alleviate the scale issue associated with sending RSVP This method can alleviate the scale issue associated with sending
messages for individual S2L sub-LSPs. However, this procedure can RSVP messages for individual S2L sub-LSPs. However, this procedure
lead to the following issues when used to re-optimize the LSP tree: can lead to the following issues when used to re-optimize the LSP
tree:
o Path message that is intended to carry the path re-evaluation o Path message that is intended to carry the path re-evaluation
request as defined in [RFC4736] with a full list of S2L sub-LSPs in request as defined in [RFC4736] with a full list of S2L sub-LSPs in
S2L sub-LSPs descriptor list will be decomposed at branching LSRs, S2L sub-LSPs descriptor list will be decomposed at branching LSRs,
and only a subset of the S2L sub-LSPs that are routed over the same and only a subset of the S2L sub-LSPs that are routed over the same
next-hop will be added in the descriptor list of the Path message next-hop will be added in the descriptor list of the Path message
propagated to downstream mid-point LSRs. Consequently, when a propagated to downstream mid-point LSRs. Consequently, when a
preferable path exists at such mid-point LSRs, the PathErr can only preferable path exists at such mid-point LSRs, the PathErr can only
include the sub-set of S2L sub-LSPs traversing the LSR. In this include the sub-set of S2L sub-LSPs traversing the LSR. In this
case, at the ingress node there is no way to distinguish which mode case, at the ingress node there is no way to distinguish which mode
of re-optimization to invoke, i.e. sub-group based re-optimization of re-optimization to invoke, i.e. sub-group based re-optimization
using the same LSP-ID or tree based re-optimization using a different using the same LSP-ID or tree based re-optimization using a different
LSP-ID. LSP-ID.
o An LSR may fragment a large RSVP message (when a combined message o An LSR may fragment a large RSVP message (when a combined message
may not be large enough to fit all S2L sub-LSPs). In this case, the may not be large enough to fit all S2L sub-LSPs). In this case, the
ingress node may receive multiple PathErrs with sub-sets of S2L ingress node may receive multiple PathErrs with sub-sets of S2L sub-
sub-LSPs in each (either due to the combined Path message got LSPs in each (due to either the combined Path message getting
fragmented or combined PathErr message got fragmented) and would fragmented or the combined PathErr message getting fragmented) and
require additional logic to infer to re-optimize the LSP tree (for would require additional logic to determine how to re-optimize the
example, waiting for some time to aggregate all possible PathErr LSP tree (for example, waiting for some time to aggregate all
messages before taking an action). When fragmented, RSVP messages possible PathErr messages before taking an action). When fragmented,
may arrive out of order, and the receiver has no way of knowing the RSVP messages may arrive out of order, and the receiver has no way of
beginning and end of the S2L sub-LSP list. knowing the beginning and end of the S2L sub-LSP list.
In order to address the above mentioned issues due to the RSVP In order to address the above mentioned issues caused by RSVP message
message fragmentation, this document defines fragment identifier for fragmentation, this document proposes the use of fragment identifier
the S2L sub-LSP descriptor list when combining large number of S2L for the S2L sub-LSP descriptor list when combining large number of
sub-LSPs in an RSVP message. S2L sub-LSPs in an RSVP message.
2. Conventions Used in This Document 2. Conventions Used in This Document
2.1. Key Word Definitions 2.1. Key Word Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2.2. Abbreviations 2.2. Abbreviations
skipping to change at page 8, line 11 skipping to change at page 8, line 11
ERO: Explicit Route Object. ERO: Explicit Route Object.
LSR: Label Switching Router. LSR: Label Switching Router.
TE LSP: Traffic Engineering Label Switched Path. TE LSP: Traffic Engineering Label Switched Path.
TE LSP ingress: Head-end/source of the TE LSP. TE LSP ingress: Head-end/source of the TE LSP.
TE LSP egress: Tail-end/destination of the TE LSP. TE LSP egress: Tail-end/destination of the TE LSP.
2.3. Nomenclatures 2.3. Terminology
Domain: Routing or administrative domain such as an IGP area and an Domain: Routing or administrative domain such as an IGP area and an
autonomous system. autonomous system.
Interior Gateway Protocol Area (IGP Area): OSPF area or IS-IS level. Interior Gateway Protocol Area (IGP Area): OSPF area or IS-IS level.
Inter-area TE LSP: A TE LSP whose path transits across at least two Inter-area TE LSP: A TE LSP whose path transits across at least two
different IGP areas. different IGP areas.
Inter-AS MPLS TE LSP: A TE LSP whose path transits across at least Inter-AS MPLS TE LSP: A TE LSP whose path transits across at least
skipping to change at page 8, line 43 skipping to change at page 8, line 43
To evaluate an entire P2MP-TE LSP tree on mid-point LSRs that expand To evaluate an entire P2MP-TE LSP tree on mid-point LSRs that expand
loose next-hop(s), an ingress node MAY send a Path message with loose next-hop(s), an ingress node MAY send a Path message with
"P2MP-TE Tree Re-evaluation Request" defined in this document. The "P2MP-TE Tree Re-evaluation Request" defined in this document. The
ingress node SHOULD select one of the S2L sub-LSPs of the P2MP-TE LSP ingress node SHOULD select one of the S2L sub-LSPs of the P2MP-TE LSP
tree transiting a mid-point LSR to trigger the re-evaluation request. tree transiting a mid-point LSR to trigger the re-evaluation request.
The ingress node MAY send a re-evaluation request to each border LSR The ingress node MAY send a re-evaluation request to each border LSR
on the path of the LSP tree. on the path of the LSP tree.
A mid-point LSR that expands loose next-hop(s) for one or more S2L A mid-point LSR that expands loose next-hop(s) for one or more S2L
sub-LSP path(s), and that receives a Path message with the "P2MP-TE sub-LSP path(s) SHOULD do the following upon receiving a Path message
Tree Re-evaluation Request" bit set: with the "P2MP-TE Tree Re-evaluation Request" bit set:
o The mid-point LSR SHOULD check for a preferable P2MP-TE LSP tree o The mid-point LSR SHOULD check for a preferable P2MP-TE LSP tree
by re-evaluating all S2L sub-LSP(s) that are expanded paths of the by re-evaluating all S2L sub-LSP(s) that are expanded paths of the
loose next-hops of the P2MP-TE LSP. loose next-hops of the P2MP-TE LSP.
o If a preferable P2MP-TE LSP tree is found, the mid-point LSR MAY o If a preferable P2MP-TE LSP tree is found, the mid-point LSR MAY
send an RSVP PathErr to the ingress node with Error code 25 (Notify send an RSVP PathErr to the ingress node with Error code 25 (Notify
defined in [RFC3209] and sub-code "Preferable P2MP-TE Tree Exists" Error) defined in [RFC3209] and sub-code "Preferable P2MP-TE Tree
defined in this document. The mid-point LSR, in turn, SHOULD NOT Exists" defined in this document. The mid-point LSR, in turn, SHOULD
propagate the "P2MP-TE Tree Re-evaluation Request" bit in subsequent NOT propagate the "P2MP-TE Tree Re-evaluation Request" bit in
RSVP Path messages sent downstream for the re-evaluated P2MP-TE LSP. subsequent RSVP Path messages sent downstream for the re-evaluated
P2MP-TE LSP.
o If no preferable tree for P2MP-TE LSP can be found, the o If no preferable tree for P2MP-TE LSP can be found, the
recommended mode is that the mid-point LSR that expands loose next- recommended mode is that the mid-point LSR that expands loose next-
hop(s) for one or more S2L sub-LSP path(s) SHOULD propagate the hop(s) for one or more S2L sub-LSP path(s) SHOULD propagate the
request downstream by setting the "P2MP-TE Tree Re-evaluation request downstream by setting the "P2MP-TE Tree Re-evaluation
Request" bit in the LSP_ATTRIBUTES Object of RSVP Path message. Request" bit in the LSP_ATTRIBUTES Object of RSVP Path message.
A mid-point LSR MAY send an unsolicited PathErr message with A mid-point LSR MAY send an unsolicited PathErr message with
"Preferable P2MP-TE Tree Exists" PathErr to the ingress node to "Preferable P2MP-TE Tree Exists" PathErr to the ingress node to
notify of a preferred P2MP-TE LSP tree when it determines it exists. notify of a preferred P2MP-TE LSP tree when it determines it exists.
skipping to change at page 10, line 18 skipping to change at page 10, line 20
list from the received fragments that may arrive out of order. list from the received fragments that may arrive out of order.
The S2L_SUB_LSP_FRAG Object defined in this document is optional. The S2L_SUB_LSP_FRAG Object defined in this document is optional.
However, a node MUST add the S2L_SUB_LSP_FRAG Object for each However, a node MUST add the S2L_SUB_LSP_FRAG Object for each
fragment in S2L sub-LSP descriptor list when the RSVP message needs fragment in S2L sub-LSP descriptor list when the RSVP message needs
to be fragmented. to be fragmented.
A mid-point LSR SHOULD wait to accumulate all S2L sub-LSPs before A mid-point LSR SHOULD wait to accumulate all S2L sub-LSPs before
attempting to re-evaluate preferable path when a Path message for attempting to re-evaluate preferable path when a Path message for
"Path Re-evaluation Request" is received with S2L_SUB_LSP_FRAG "Path Re-evaluation Request" is received with S2L_SUB_LSP_FRAG
Object. An ingress node SHOULD wait to accumulate all S2L sub-LSPs Object. If a mid-point LSR does not receive all fragments of the
before attempting to trigger re-optimization when a PathErr message Path message (for example, when fragments are lost), it SHOULD
with "Preferable Path Exists" is received with a S2L_SUB_LSP_FRAG trigger re-evaluation of all S2L sub-LSPs of the P2MP-TE LSP
Object. transiting on the node. An ingress node SHOULD wait to accumulate
all S2L sub-LSPs before attempting to trigger re-optimization when a
PathErr message with "Preferable Path Exists" is received with a
S2L_SUB_LSP_FRAG Object. If an ingress node does not receive all
fragments of the PathErr message (for example, when fragments are
lost), it SHOULD trigger re-optimization of all S2L sub-LSPs of the
P2MP-TE LSP transiting on the mid-point node that had sent the
PathErr message.
The new object S2L_SUB_LSP_FRAG defined in this document has a wider The new object S2L_SUB_LSP_FRAG defined in this document has a wider
applicability other than the P2MP-TE LSP re-optimization but it is applicability other than the P2MP-TE LSP re-optimization but it is
outside the scope of this document. outside the scope of this document.
4. Message and Object Definitions 4. Message and Object Definitions
4.1. P2MP-TE Tree Re-evaluation Request Flag 4.1. P2MP-TE Tree Re-evaluation Request Flag
In order to trigger a tree re-evaluation request, a new flag is In order to trigger a tree re-evaluation request, a new flag is
skipping to change at page 11, line 18 skipping to change at page 11, line 24
4.3. Fragment Identifier For S2L sub-LSP Descriptor 4.3. Fragment Identifier For S2L sub-LSP Descriptor
An S2L_SUB_LSP Object [RFC4875] identifies a particular S2L sub-LSP An S2L_SUB_LSP Object [RFC4875] identifies a particular S2L sub-LSP
belonging to the P2MP-TE LSP. An S2L sub-LSP descriptor list is belonging to the P2MP-TE LSP. An S2L sub-LSP descriptor list is
created using a series of S2L_SUB_LSP Objects as defined in created using a series of S2L_SUB_LSP Objects as defined in
[RFC4875]. The RSVP message may need to be fragmented due to large [RFC4875]. The RSVP message may need to be fragmented due to large
number of S2L sub-LSPs added in the descriptor list, and such number of S2L sub-LSPs added in the descriptor list, and such
fragments may be received our of order. To be able to rebuild the fragments may be received our of order. To be able to rebuild the
fragmented S2L sub-LSP descriptor list correctly, the following new fragmented S2L sub-LSP descriptor list correctly, the following new
type is defined for the S2L_SUB_LSP Object [RFC4875]. type is defined for the S2L_SUB_LSP Object [RFC4875] to identify the
fragments.
S2L_SUB_LSP_FRAG: Class-Num 50, C-Type TBA by IANA S2L_SUB_LSP_FRAG: Class-Num 50, C-Type TBA3 by IANA
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| Len (12 bytes)| Reserved | Class_Num 50 | SUB_LSP_FRAG | | Length (12 bytes) | Class-Num 50 | C-Type TBA3 |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| Reserved | Fragment ID | | Reserved | Fragment ID |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| Fragments Total | Fragment Number | | Fragments Total | Fragment Number |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Fragment ID: 16-bit integer in the range of 1 to 65535. This value Fragment ID: 16-bit integer in the range of 1 to 65535. This value
is incremented for each new RSVP message that needs to be is incremented for each new RSVP message that needs to be
fragmented. fragmented. The scope of the fragment ID is limited to the RSVP
message type (e.g. Path) carrying the fragment. In other words,
fragment IDs do not have any correlation between different RSVP
message types (e.g. Path and PathErr).
Fragments Total: 16-bit integer in the range of 1 to 65535. This Fragments Total: 16-bit integer in the range of 1 to 65535. This
value indicates the number of fragments sent for the given RSVP value indicates the number of fragments sent for the given RSVP
message. message.
Fragment Number: 16-bit integer in the range of 1 to 65535. This Fragment Number: 16-bit integer in the range of 1 to 65535. This
value indicates the position of this fragment in the given RSVP value indicates the position of this fragment in the given RSVP
message. message.
The S2L_SUB_LSP_FRAG Object is added before adding the The S2L_SUB_LSP_FRAG Object is added before adding the
S2L_SUB_LSP_IPv4 or S2L_SUB_LSP_IPv6 Object in the fragmented S2L_SUB_LSP_IPv4 or S2L_SUB_LSP_IPv6 Object in the fragmented RSVP
message. message.
5. Compatibility 5. Compatibility
The LSP_ATTRIBUTES Object has been defined in [RFC5420] with class The LSP_ATTRIBUTES Object has been defined in [RFC5420] with class
numbers in the form 11bbbbbb, which ensures compatibility with numbers in the form 11bbbbbb, which ensures compatibility with
non-supporting nodes. Per [RFC2205], nodes not supporting this non-supporting nodes. Per [RFC2205], nodes not supporting this
extension will ignore the new flag defined in this document but extension will ignore the new flag defined in this document but
forward it without modification. forward it without modification.
skipping to change at page 12, line 41 skipping to change at page 12, line 49
The following new flag is defined for the Attributes Flags TLV in the The following new flag is defined for the Attributes Flags TLV in the
LSP_ATTRIBUTES Object [RFC5420]. The numeric value is to be assigned LSP_ATTRIBUTES Object [RFC5420]. The numeric value is to be assigned
by IANA. by IANA.
o P2MP-TE Tree Re-evaluation Request Flag: o P2MP-TE Tree Re-evaluation Request Flag:
+--------+---------------+---------+---------+---------+------------+ +--------+---------------+---------+---------+---------+------------+
| Bit No | Attribute | Carried | Carried | Carried | Reference | | Bit No | Attribute | Carried | Carried | Carried | Reference |
| | Flag Name | in Path | in Resv | in RRO | | | | Flag Name | in Path | in Resv | in RRO | |
+--------+---------------+---------+---------+---------+------------+ +--------+---------------+---------+---------+---------+------------+
| TBA by | P2MP-TE Tree | Yes | No | No | This | | TBA1 by| P2MP-TE Tree | Yes | No | No | This |
| IANA | Re-evaluation | | | | document | | IANA | Re-evaluation | | | | document |
+--------+---------------+---------+---------+---------+------------+ +--------+---------------+---------+---------+---------+------------+
6.2. Preferable P2MP-TE Tree Exists Path Error Sub-code 6.2. Preferable P2MP-TE Tree Exists Path Error Sub-code
IANA maintains a name space for RSVP protocol parameters "Resource IANA maintains a name space for RSVP protocol parameters "Resource
Reservation Protocol (RSVP) Parameters" (see Reservation Protocol (RSVP) Parameters" (see
http://www.iana.org/assignments/rsvp-parameters). From the http://www.iana.org/assignments/rsvp-parameters). From the
sub-registry "Sub-Codes - 25 Notify Error" in registry "Error Codes sub-registry "Sub-Codes - 25 Notify Error" in registry "Error Codes
and Globally-Defined Error Value Sub-Codes", allocation of a new and Globally-Defined Error Value Sub-Codes", allocation of a new
skipping to change at page 13, line 18 skipping to change at page 13, line 24
As defined in [RFC3209], the Error Code 25 in the ERROR SPEC Object As defined in [RFC3209], the Error Code 25 in the ERROR SPEC Object
corresponds to a Notify Error PathErr. This document adds a new corresponds to a Notify Error PathErr. This document adds a new
sub-code for this PathErr as follows: sub-code for this PathErr as follows:
o Preferable P2MP-TE Tree Exists sub-code: o Preferable P2MP-TE Tree Exists sub-code:
+----------+--------------------+---------+---------+-----------+ +----------+--------------------+---------+---------+-----------+
| Sub-code | Sub-code | PathErr | PathErr | Reference | | Sub-code | Sub-code | PathErr | PathErr | Reference |
| value | Description | Code | Name | | | value | Description | Code | Name | |
+----------+--------------------+---------+---------+-----------+ +----------+--------------------+---------+---------+-----------+
| TBA by | Preferable P2MP-TE | 25 | Notify | This | | TBA2 by | Preferable P2MP-TE | 25 | Notify | This |
| IANA | Tree Exists | | Error | document | | IANA | Tree Exists | | Error | document |
+----------+--------------------+---------+---------+-----------+ +----------+--------------------+---------+---------+-----------+
6.3. Fragment Identifier For S2L sub-LSP Descriptor 6.3. Fragment Identifier For S2L sub-LSP Descriptor
IANA maintains a name space for RSVP protocol parameters "Resource IANA maintains a name space for RSVP protocol parameters "Resource
Reservation Protocol (RSVP) Parameters" (see Reservation Protocol (RSVP) Parameters" (see
http://www.iana.org/assignments/rsvp-parameters). From the http://www.iana.org/assignments/rsvp-parameters). From the
sub-registry "Class Types or C-Types 50 S2L_SUB_LSP" in registry sub-registry "Class Types or C-Types 50 S2L_SUB_LSP" in registry
"Class Names, Class Numbers, and Class Types", allocation of new "Class Names, Class Numbers, and Class Types", allocation of new
skipping to change at page 13, line 41 skipping to change at page 13, line 47
As defined in [RFC4875], S2L_SUB_LSP Object is defined with As defined in [RFC4875], S2L_SUB_LSP Object is defined with
Class-Number 50 to identify a particular S2L sub-LSP belonging to the Class-Number 50 to identify a particular S2L sub-LSP belonging to the
P2MP-TE LSP. This document adds one new object type for this object P2MP-TE LSP. This document adds one new object type for this object
as follows: as follows:
o S2L_SUB_LSP_FRAG Object type: o S2L_SUB_LSP_FRAG Object type:
+-----------------+---------------------------+-----------------+ +-----------------+---------------------------+-----------------+
| C-Type value | Description | Reference | | C-Type value | Description | Reference |
+-----------------+---------------------------+-----------------+ +-----------------+---------------------------+-----------------+
| TBA by IANA | S2L_SUB_LSP_FRAG | This document | | TBA3 by IANA | S2L_SUB_LSP_FRAG | This document |
+-----------------+---------------------------+-----------------+ +-----------------+---------------------------+-----------------+
7. Security Considerations 7. Security Considerations
This document defines RSVP-TE signaling extensions to allow an This document defines RSVP-TE signaling extensions to allow an
ingress node of a P2MP-TE LSP to request the re-evaluation of the ingress node of a P2MP-TE LSP to request the re-evaluation of the
entire LSP tree, and for a mid-point LSR to notify the ingress node entire LSP tree, and for a mid-point LSR to notify the ingress node
of the existence of a preferable tree by sending a PathErr. As per of the existence of a preferable tree by sending a PathErr. As per
[RFC4736], in the case of a P2MP-TE LSP S2L sub-LSP spanning multiple [RFC4736], in the case of a P2MP-TE LSP S2L sub-LSP spanning multiple
domains, it may be desirable for a mid-point LSR to modify the RSVP domains, it may be desirable for a mid-point LSR to modify the RSVP
skipping to change at page 15, line 30 skipping to change at page 15, line 30
[RFC4736] Vasseur, JP., Ikejiri, Y. and Zhang, R, "Reoptimization of [RFC4736] Vasseur, JP., Ikejiri, Y. and Zhang, R, "Reoptimization of
Multiprotocol Label Switching (MPLS) Traffic Engineering Multiprotocol Label Switching (MPLS) Traffic Engineering
(TE) Loosely Routed Label Switched Path (LSP)", RFC 4736, (TE) Loosely Routed Label Switched Path (LSP)", RFC 4736,
November 2006. November 2006.
[RFC4875] Aggarwal, R., Papadimitriou, D., and S. Yasukawa, [RFC4875] Aggarwal, R., Papadimitriou, D., and S. Yasukawa,
"Extensions to Resource Reservation Protocol Traffic "Extensions to Resource Reservation Protocol Traffic
Engineering (RSVP-TE) for Point-to-Multipoint TE Label Engineering (RSVP-TE) for Point-to-Multipoint TE Label
Switched Paths (LSPs)", RFC 4875, May 2007. Switched Paths (LSPs)", RFC 4875, May 2007.
[RFC5420] Farrel, A., Papadimitriou, D., Vasseur, JP., and A. [RFC5420] Farrel, A., Papadimitriou, D., Vasseur, JP., and Ayyangar,
Ayyangarps, "Encoding of Attributes for MPLS LSP A., "Encoding of Attributes for MPLS LSP Establishment
Establishment Using Resource Reservation Protocol Traffic Using Resource Reservation Protocol Traffic Engineering
Engineering (RSVP-TE)", RFC 5420, February 2009. (RSVP-TE)", RFC 5420, February 2009.
8.2. Informative References 8.2. Informative References
[RFC5440] Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path Computation [RFC5440] Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440, Element (PCE) Communication Protocol (PCEP)", RFC 5440,
March 2009. March 2009.
[RFC5920] Fang, L., "Security Framework for MPLS and GMPLS [RFC5920] Fang, L., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010. Networks", RFC 5920, July 2010.
Acknowledgments Acknowledgments
The authors would like to thank Loa Andersson, Sriganesh Kini, Curtis The authors would like to thank Loa Andersson, Sriganesh Kini, Curtis
Villamizar, Dimitri Papadimitriou, Nobo Akiya and Vishnu Pavan Beeram Villamizar, Dimitri Papadimitriou, Nobo Akiya and Vishnu Pavan Beeram
for reviewing this document. The authors would also like to thank for reviewing this document and providing many useful comments and
Ling Zeng for implementing mechanisms defined in this document. suggestions. The authors would also like to thank Ling Zeng with
Cisco Systems for implementing mechanisms defined in this document.
Author's Addresses Author's Addresses
Tarek Saad (editor) Tarek Saad (editor)
Cisco Systems Cisco Systems
EMail: tsaad@cisco.com EMail: tsaad@cisco.com
Rakesh Gandhi (editor) Rakesh Gandhi (editor)
Cisco Systems Cisco Systems
 End of changes. 29 change blocks. 
93 lines changed or deleted 110 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/