draft-ietf-manet-dlep-da-credit-extension-02.txt   draft-ietf-manet-dlep-da-credit-extension-03.txt 
Network Working Group B. Cheng Network Working Group B. Cheng
Internet-Draft D. Wiggins Internet-Draft D. Wiggins
Intended status: Standards Track Lincoln Laboratory Intended status: Standards Track Lincoln Laboratory
Expires: May 3, 2018 L. Berger Expires: May 15, 2018 L. Berger
LabN Consulting, L.L.C. LabN Consulting, L.L.C.
October 30, 2017 November 11, 2017
DLEP DiffServ Aware Credit Windowing Extension DLEP DiffServ Aware Credit Windowing Extension
draft-ietf-manet-dlep-da-credit-extension-02 draft-ietf-manet-dlep-da-credit-extension-03
Abstract Abstract
This document defines an extension to the DLEP protocol that enables This document defines an extension to the DLEP protocol that enables
a DiffServ aware credit-windowing scheme for destination-specific and a DiffServ aware credit-windowing scheme for destination-specific and
shared flow control. shared flow control.
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
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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 https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 3, 2018. This Internet-Draft will expire on May 15, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Extension Overview . . . . . . . . . . . . . . . . . . . . . 3 2. Extension Overview . . . . . . . . . . . . . . . . . . . . . 3
3. Extension Usage and Identification . . . . . . . . . . . . . 5 3. Extension Usage and Identification . . . . . . . . . . . . . 5
4. Data Plane Considerations . . . . . . . . . . . . . . . . . . 5 4. Data Plane Considerations . . . . . . . . . . . . . . . . . . 5
5. Extension Messages . . . . . . . . . . . . . . . . . . . . . 5 5. Extension Messages . . . . . . . . . . . . . . . . . . . . . 5
5.1. Credit Control Message . . . . . . . . . . . . . . . . . 5 5.1. Credit Control Message . . . . . . . . . . . . . . . . . 5
5.2. Credit Control Response Message . . . . . . . . . . . . . 6 5.2. Credit Control Response Message . . . . . . . . . . . . . 6
6. Extension Data Items . . . . . . . . . . . . . . . . . . . . 6 6. Extension Data Items . . . . . . . . . . . . . . . . . . . . 7
6.1. Credit Window Initialization . . . . . . . . . . . . . . 7 6.1. Credit Window Initialization . . . . . . . . . . . . . . 7
6.2. Credit Window Traffic Classification . . . . . . . . . . 9 6.2. Credit Window Traffic Classification . . . . . . . . . . 9
6.2.1. Traffic Classification Sub Data Item . . . . . . . . 11 6.2.1. Traffic Classification Sub Data Item . . . . . . . . 11
6.2.2. DiffServ Traffic Classification Sub Data Item . . . . 11 6.2.2. DiffServ Traffic Classification Sub Data Item . . . . 12
6.3. Credit Window Associate . . . . . . . . . . . . . . . . . 13 6.3. Credit Window Associate . . . . . . . . . . . . . . . . . 13
6.4. Credit Window Credit Grant . . . . . . . . . . . . . . . 14 6.4. Credit Window Credit Grant . . . . . . . . . . . . . . . 14
6.5. Credit Window Status . . . . . . . . . . . . . . . . . . 15 6.5. Credit Window Status . . . . . . . . . . . . . . . . . . 16
6.6. Credit Window Request . . . . . . . . . . . . . . . . . . 17 6.6. Credit Window Request . . . . . . . . . . . . . . . . . . 17
7. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 18 7. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 18
8. Security Considerations . . . . . . . . . . . . . . . . . . . 18 8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
9.1. Extension Type Value . . . . . . . . . . . . . . . . . . 18 9.1. Extension Type Value . . . . . . . . . . . . . . . . . . 19
9.2. Message Values . . . . . . . . . . . . . . . . . . . . . 19 9.2. Message Values . . . . . . . . . . . . . . . . . . . . . 19
9.3. Data Item Values . . . . . . . . . . . . . . . . . . . . 19 9.3. Data Item Values . . . . . . . . . . . . . . . . . . . . 19
9.4. DLEP Sub Data Item Registry . . . . . . . . . . . . . . . 20 9.4. DLEP Sub Data Item Registry . . . . . . . . . . . . . . . 20
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
10.1. Normative References . . . . . . . . . . . . . . . . . . 20 10.1. Normative References . . . . . . . . . . . . . . . . . . 21
10.2. Informative References . . . . . . . . . . . . . . . . . 21 10.2. Informative References . . . . . . . . . . . . . . . . . 21
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 21 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 22
Appendix B. Open and Resolved Issues . . . . . . . . . . . . . . 21 Appendix B. Open and Resolved Issues . . . . . . . . . . . . . . 22
B.1. Merge with [I-D.ietf-manet-credit-window] . . . . . . . . 21 B.1. Merge with [I-D.ietf-manet-credit-window] . . . . . . . . 22
B.2. Supporting Router Limits . . . . . . . . . . . . . . . . 22 B.2. Supporting Router Limits . . . . . . . . . . . . . . . . 22
B.3. Absolute vs Increment . . . . . . . . . . . . . . . . . . 22 B.3. Absolute vs Increment . . . . . . . . . . . . . . . . . . 23
B.4. Bidirectional Flow B.4. Bidirectional Flow
Control (closed) . . . . . . . . . . . . . . . . . . . . 22 Control (closed) . . . . . . . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction 1. Introduction
The Dynamic Link Event Protocol (DLEP) is defined in [RFC8175]. It The Dynamic Link Event Protocol (DLEP) is defined in [RFC8175]. It
provides the exchange of link related control information between provides the exchange of link related control information between
DLEP peers. DLEP peers are comprised of a modem and a router. DLEP DLEP peers. DLEP peers are comprised of a modem and a router. DLEP
defines a base set of mechanisms as well as support for possible defines a base set of mechanisms as well as support for possible
extensions. This document defines one such extension. extensions. This document defines one such extension.
The base DLEP specification does not include any flow control The base DLEP specification does not include any flow control
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capitals, as shown here. capitals, as shown here.
2. Extension Overview 2. Extension Overview
The DA Credit extension can be used to support credit based flow The DA Credit extension can be used to support credit based flow
control of traffic sent from a router to a modem. The extension can control of traffic sent from a router to a modem. The extension can
be used to support DiffServ and non-DiffServ based flow control. be used to support DiffServ and non-DiffServ based flow control.
Both types of DLEP endpoints, i.e., a router and a modem, negotiate Both types of DLEP endpoints, i.e., a router and a modem, negotiate
the use of extension during session initialization, see Section 5.2 the use of extension during session initialization, see Section 5.2
[RFC8175]. When using this extension, data is allowed to be sent by [RFC8175]. When using this extension, data traffic is allowed to be
the router to the modem only when there are credits available. sent by the router to the modem only when there are credits
available.
Credits are managed on a per logical "Credit Windows" basis. Each Credits are managed on a per logical "Credit Windows" basis. Each
credit window can be thought of as corresponding to a queue within a credit window can be thought of as corresponding to a queue within a
modem. Modems pass to the router information on its credit windows modem. Modems pass to the router information on its credit windows
and identify each via a "Credit Window Identifier", or "CID". In and identify each via a "Credit Window Identifier", or "CID". In
addition to the CID, credit window information includes an initial addition to the CID, credit window information includes an initial
credit window size, as well as the maximum size of the logical queue credit window size, as well as the maximum size of the logical queue
associated with each CID. The maximum size is included for associated with each CID. The maximum size is included for
informative and, potential, future uses. informative and, potential, future uses.
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Item. The Extensions Supported Data Item is sent and processed Item. The Extensions Supported Data Item is sent and processed
according to [RFC8175]. according to [RFC8175].
The DiffServ Aware Credit Windowing Extension Type Value is TBA1, see The DiffServ Aware Credit Windowing Extension Type Value is TBA1, see
Section 9. Section 9.
4. Data Plane Considerations 4. Data Plane Considerations
When the use of the extension defined in this document is agreed upon When the use of the extension defined in this document is agreed upon
per standard DLEP processing, see Section 3, a router MUST NOT send per standard DLEP processing, see Section 3, a router MUST NOT send
data to a modem for forwarding when there are no credits available in data traffic to a modem for forwarding when there are no credits
the associated Credit Window. This document defines credit windows available in the associated Credit Window. This document defines
in octets. A credit window value MUST be larger than the number of credit windows in octets. A credit window value MUST be larger than
octets contained in a packet, including any MAC headers used between the number of octets contained in a packet, including any MAC headers
the router and the modem, in order for the router to send the packet used between the router and the modem, in order for the router to
to a modem for forwarding. The credit window is decremented by the send the packet to a modem for forwarding. The credit window is
number of sent octets. decremented by the number of sent octets.
A router MUST identify the credit window associated with traffic sent A router MUST identify the credit window associated with traffic sent
to a modem based on the traffic classification information provided to a modem based on the traffic classification information provided
in the data items defined in this document. The definitions support in the data items defined in this document. The definitions support
identification based on DLEP destination and, at the modem's identification based on DLEP destination and, at the modem's
discretion, DSCPs. Note that routers will typically view a DLEP discretion, DSCPs. Note that routers will typically view a DLEP
destination as the next hop. destination as the next hop.
5. Extension Messages 5. Extension Messages
Two new messages are defined by this extension: the Credit Control Two new messages are defined by this extension: the Credit Control
and the Credit Control Response Message. Sending and receiving both and the Credit Control Response Message. Sending and receiving both
message types MUST be supported by any implementation that advertises message types MUST be supported by any implementation that advertises
use of this extension per Section 3. use of this extension per Section 3.
5.1. Credit Control Message 5.1. Credit Control Message
Credit Control Messages are sent by modems to provide credit window Credit Control Messages are sent by modems and routers. Each sender
increases. For messages sent by modems, only one message can be is only permitted to have one message outstanding at one time. That
outstanding at one time. That is, a modem MUST NOT send a second (or is, a sender (modem or router) MUST NOT send a second (or any
any subsequent) Credit Control Message until a Credit Control subsequent) Credit Control Message until a Credit Control Response
Response Message is received from its peer router. Message is received from its peer (router or modem).
Credit Control Messages MAY be sent by routers, e.g., to request Credit Control Messages are sent by modems to provide credit window
credits or provide window status. No specific response message is increases. Modems send credit increases when there is transmission
required from a modem from a message transaction perspective. There or local queue availability that exceeds the credit window value
is no restriction on when a router can send a Credit Control Message. previous provided to the router. Modems will need to balance the
load generated by sending and processing frequent credit window
increases against a router having data traffic available to send, but
no credits available.
[TBD: Should anything be said about sending, or limiting, multiple Credit Control Messages MAY be sent by routers to request credits and
credit requests?] provide window status. Routers will need to balance the load
generated by sending and processing frequent credit window requests
against a having data traffic available to send, but no credits
available.
The Message Type value in the DLEP Message Header is set to TBA2. The Message Type value in the DLEP Message Header is set to TBA2.
A message sent by a modem, MUST contain one or more Credit Window A message sent by a modem, MUST contain one or more Credit Window
Grant Data Items as defined below in Section 6.4. A router receiving Grant Data Items as defined below in Section 6.4. A router receiving
this message MUST respond with a Credit Control Response Message. this message MUST respond with a Credit Control Response Message.
A message sent by a router, MUST contain the Credit Window Request A message sent by a router, MUST contain one or more Credit Window
Data Item defined below in Section 6.6. A modem receiving this Request Data Items defined below in Section 6.6 and SHOULD contain a
message MUST process the received message and data item as defined Credit Window Status Data Item, defined in Section 6.5, corresponding
below, which will result in credit window increments being provided to each credit window request. A modem receiving this message MUST
via Credit Window Grant Data Items carried in one more more new respond with a Credit Control Response Message based on the received
Credit Control Message. message and data item and the processing defined below, which will
typically result in credit window increments being provided.
Specific processing associated with each Credit Data Item is provided Specific processing associated with each Credit Data Item is provided
below. below.
5.2. Credit Control Response Message 5.2. Credit Control Response Message
Credit Control Response Messages are sent by routers to report the Credit Control Response Messages are sent by routers to report the
current Credit Window for a destination. current Credit Window for a destination. A message sent by a router,
MUST contain one or more Credit Window Status Data Items as defined
The Message Type value in the DLEP Message Header is set to TBA3. below in Section 6.5. Specific receive processing associated with
the Credit Window Window Status Data Item is provided below.
A message sent by a router, MUST contain one or more Credit Window Credit Control Response Messages sent by modems MUST contain one or
Status data items as defined below in Section 6.5. more Credit Window Credit Grant Data Items. A data item for every
Credit Window Request data item contained in the for Credit Control
Response Message sent by the router MUST be included. Each Grant
Data Item MAY provide zero or more additional credits based on a the
modem;s transmission or local queue availability. Specific receive
processing associated with each Grant Data Item is provided below.
Specific processing associated with the Credit Window Window Status The Message Type value in the DLEP Message Header is set to TBA3.
Data Item is provided below.
6. Extension Data Items 6. Extension Data Items
Six data items are defined by this extension. The Credit Window Six data items are defined by this extension. The Credit Window
Initialization Data Item is used by a modem to identify a credit Initialization Data Item is used by a modem to identify a credit
window and set its size. The Credit Window Traffic Classification window and set its size. The Credit Window Traffic Classification
Data Item is used by a modem to identify a set which identifies which Data Item is used by a modem to identify a set which identifies which
DSCPs are mapped to a credit window. The Credit Window Association DSCPs are mapped to a credit window. The Credit Window Association
Data Item is used by a modem to identify which traffic classification Data Item is used by a modem to identify which traffic classification
set should be used when sending traffic to a particular DLEP set should be used when sending traffic to a particular DLEP
identified destination. The Credit Window Grant is used by a modem identified destination. The Credit Window Grant is used by a modem
to provide additional credits to a router. The Credit Request is to provide additional credits to a router. The Credit Request is
used by a router to request additional credits. The Credit Window used by a router to request additional credits. The Credit Window
Status is used to advertise the sender's view of number of available Status is used to advertise the sender's view of number of available
credits for state synchronization purposes. credits for state synchronization purposes.
Any errors or inconsistencies encountered in parsing data items are Any errors or inconsistencies encountered in parsing data items are
handled in the same fashion as any other Data Item parsing error handled in the same fashion as any other data dtem parsing error
encountered in DLEP, see [RFC8175]. In particular, the node parsing encountered in DLEP, see [RFC8175]. In particular, the node parsing
the data item MUST terminate the session with a Status Data Item the data item MUST terminate the session with a Status Data Item
indicating Invalid Data. indicating Invalid Data.
The defined data items and operations have similar objectives as The defined data items and operations have similar objectives as
those found in [I-D.ietf-manet-credit-window]. One notable those found in [I-D.ietf-manet-credit-window]. One notable
difference from this extension is that in this document credits are difference from this extension is that in this document credits are
never provided by the router to the modem. never provided by the router to the modem.
6.1. Credit Window Initialization 6.1. Credit Window Initialization
The Credit Window Initialization Data Item is used by a modem to The Credit Window Initialization Data Item is used by a modem to
identify a credit window and set its size. This data item SHOULD be identify a credit window and set its size. This Data Item SHOULD be
included in any Session Initialization Response Message that also included in any Session Initialization Response Message that also
contains the DiffServ Aware Credit Windowing Extension Type Value in contains the DiffServ Aware Credit Windowing Extension Type Value in
the Extensions Supported Data Item. Updates to previously identified the Extensions Supported Data Item. Updates to previously identified
credit windows or new credit windows MAY be sent by a modem by credit windows or new credit windows MAY be sent by a modem by
including the data item in Session Update Messages. More than one including the data item in Session Update Messages. More than one
data item MAY be included in a message to provide information on data item MAY be included in a message to provide information on
multiple credit windows. multiple credit windows.
The Credit Window Initialization Data Item identifies a credit window The Credit Window Initialization Data Item identifies a credit window
using a Credit Window Identifier, or CID. It also provides the size using a Credit Window Identifier, or CID. It also provides the size
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Data Item Type: TBA4 Data Item Type: TBA4
Length: 16 Length: 16
Per [RFC8175] Length is the number of octets in the data item, Per [RFC8175] Length is the number of octets in the data item,
excluding the Type and Length fields. excluding the Type and Length fields.
Credit Window Identifier (CID): Credit Window Identifier (CID):
A 16-bit unsigned integer identifying a credit window. The value A 16-bit unsigned integer identifying a credit window. The value
of 0xFFFFFFFF is reserved and MUST not be used in this Data Item. of 0xFFFFFFFF is reserved and MUST not be used in this data item.
There is no other restriction on values used by a modem, and there There is no other restriction on values used by a modem, and there
is no requirement for sequential or ordered values. is no requirement for sequential or ordered values.
Reserved: Reserved:
MUST be set to zero by the sender (a modem) and ignored by the MUST be set to zero by the sender (a modem) and ignored by the
receiver (a router). receiver (a router).
Credit Value: Credit Value:
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3 GB - Gigabytes (MB/1024) 3 GB - Gigabytes (MB/1024)
Credit Window Size: Credit Window Size:
A 24-bit unsigned integer representing the maximum size, in the A 24-bit unsigned integer representing the maximum size, in the
octet scale indicated by the Scale field, of the associated credit octet scale indicated by the Scale field, of the associated credit
window. window.
A router that receives a Credit Window Initialization Data Item MUST A router that receives a Credit Window Initialization Data Item MUST
locate the credit window that is associated with the CID indicated in locate the credit window that is associated with the CID indicated in
each received Data Item. If no associated credit window is found, each received data item. If no associated credit window is found,
the router MUST initialize a new credit window using the values the router MUST initialize a new credit window using the values
carried in the Data Item. When an associated credit window is found, carried in the data item. When an associated credit window is found,
the router MUST update the credit window using the values carried in the router MUST update the credit window using the values carried in
the Data Item. It is worth noting, that such updates can result in a the Data Item. It is worth noting, that such updates can result in a
credit window size being reduced, for example, due to a transmission credit window size being reduced, for example, due to a transmission
rate change on the modem. rate change on the modem.
6.2. Credit Window Traffic Classification 6.2. Credit Window Traffic Classification
The Credit Window Traffic Classification Data Item is used by a modem The Credit Window Traffic Classification Data Item is used by a modem
to provide information to enable router to identify the credit window to provide information to enable router to identify the credit window
associated with traffic the router sends. Each data item includes a associated with traffic the router sends. Each data item includes a
set of credit windows and provides traffic classification for each set of credit windows and provides traffic classification for each
window. The data item is defined to support classification based on window. The data item is defined to support classification based on
DSCPs, but is designed to be extensible for future traffic DSCPs, but is designed to be extensible for future traffic
classification types. The data item is not required to provide full classification types. The data item is not required to provide full
traffic classification information. In the context of the definition traffic classification information. In the context of the definition
included in this document, the DLEP destination address needed to included in this document, the DLEP destination address needed to
complete the traffic classification information is provided by a complete the traffic classification information is provided by a
modem when it identifies the traffic classification set in a modem when it identifies the traffic classification set in a
Destination Up message using the Credit Window Associate Data Item Destination Up Message using the Credit Window Associate Data Item
defined below. defined below.
The Credit Window Traffic Classification Data Item SHOULD be included The Credit Window Traffic Classification Data Item SHOULD be included
by a modem in any Session Initialization Response Message that also by a modem in any Session Initialization Response Message that also
contains the DiffServ Aware Credit Windowing Extension Type Value in contains the DiffServ Aware Credit Windowing Extension Type Value in
the Extensions Supported Data Item. Updates to previously provided the Extensions Supported Data Item. Updates to previously provided
traffic classifications or new traffic classifications MAY be sent by traffic classifications or new traffic classifications MAY be sent by
a modem by including the data item in Session Update Messages. More a modem by including the data item in Session Update Messages. More
than one data item MAY be included in a message to provide than one data item MAY be included in a message to provide
information on multiple traffic classifiers. information on multiple traffic classifiers.
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receiver (a router). receiver (a router).
Traffic Classification Sub Data Item: Traffic Classification Sub Data Item:
Zero or more Traffic Classification Sub Data Items of the format Zero or more Traffic Classification Sub Data Items of the format
defined below MAY be included. The number MUST match the value defined below MAY be included. The number MUST match the value
carried in the Num SDIs field. carried in the Num SDIs field.
A router receiving the Traffic Classification Data Item MUST locate A router receiving the Traffic Classification Data Item MUST locate
the traffic classification information that is associated with the the traffic classification information that is associated with the
TID indicated in each received Data Item. If no associated traffic TID indicated in each received data item. If no associated traffic
classification information is found, the router MUST initialize a new classification information is found, the router MUST initialize a new
information set using the values carried in the Data Item. When information set using the values carried in the data item. When
associated traffic classification information is found, the router associated traffic classification information is found, the router
MUST update the information using the values carried in the Data MUST update the information using the values carried in the Data
Item. In both cases, a router MUST also ensure that any data plane Item. In both cases, a router MUST also ensure that any data plane
state, see Section 4, that is associated with the TID is updated as state, see Section 4, that is associated with the TID is updated as
needed. needed.
6.2.1. Traffic Classification Sub Data Item 6.2.1. Traffic Classification Sub Data Item
All Traffic Classification Sub Data Items share a common format that All Traffic Classification Sub Data Items share a common format that
is patterned after the standard DLEP data item format, see [RFC8175] is patterned after the standard DLEP data item format, see [RFC8175]
Section 11.3. There is no requirement on, or meaning to Sub Data Section 11.3. There is no requirement on, or meaning to sub data
Item ordering. Any errors or inconsistencies encountered in parsing item ordering. Any errors or inconsistencies encountered in parsing
Sub Data Items are handled in the same fashion as any other Data Item sub data items are handled in the same fashion as any other data item
parsing error encountered in DLEP. parsing error encountered in DLEP.
The format of the Traffic Classification Sub Data Item is: The format of the Traffic Classification Sub Data Item is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub Data Item Type | Length | | Sub Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... : | Value... :
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+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
| DSCP | CU | | DSCP | CU |
+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
DSCP: differentiated services codepoint DSCP: differentiated services codepoint
CU: currently unused, MUST be zero CU: currently unused, MUST be zero
A router receiving the DiffServ Traffic Classification Sub Data Item A router receiving the DiffServ Traffic Classification Sub Data Item
MUST validate the information on receipt prior to the information and MUST validate the information on receipt prior to the information and
data plan update described earlier in this section. The credit data plan update described earlier in this section. The credit
window associated with the CID indicated in each Data Item must be window associated with the CID indicated in each data item must be
located. It is important to note that the CID value may be present located. It is important to note that the CID value may be present
in a Credit Window Initialization Data Item carried in the same in a Credit Window Initialization Data Item carried in the same
message as the Sub Data Item. If the CID is not located, the it MUST message as the sub data item. If the CID is not located, the it MUST
be treated as an error as described above. be treated as an error as described above.
In the case there are no unknown CIDs, the receiver MUST ensure that In the case there are no unknown CIDs, the receiver MUST ensure that
each DS Field value is listed only once across the whole Credit each DS Field value is listed only once across the whole Credit
Window Traffic Classification Data Item. Note, this check is across Window Traffic Classification Data Item. Note, this check is across
the Data Item and not the individual Sub Data Item. If the same DS the data item and not the individual sub data item. If the same DS
Field value is listed more than once within the same Credit Window Field value is listed more than once within the same Credit Window
Traffic Classification Data Item, the Data Item MUST be treated as an Traffic Classification Data Item, the data item MUST be treated as an
error as described above. error as described above.
6.3. Credit Window Associate 6.3. Credit Window Associate
The Credit Window Associate Data Item is used by a modem to associate The Credit Window Associate Data Item is used by a modem to associate
traffic classification information with a destination. The traffic traffic classification information with a destination. The traffic
classification information is identified using a TID value that has classification information is identified using a TID value that has
been previously been sent by the modem or is listed in a Credit been previously been sent by the modem or is listed in a Credit
Window Traffic Classification Data Item carried in the same message Window Traffic Classification Data Item carried in the same message
as the data item. as the data item.
A single Credit Window Associate Data Item MUST be included in all A single Credit Window Associate Data Item MUST be included in all
Destination Up and Destination Update Messages sent by a modem when Destination Up and Destination Update Messages sent by a modem when
the use of the extension defined in this document is agreed upon, see the use of the extension defined in this document is agreed upon, see
Section 3. Section 3.
The format of the Credit Window Traffic Classification Data Item is: The format of the Credit Window Associate Data Item is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length (2) | | Data Item Type | Length (2) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Traffic Class. Identifier (TID)| |Traffic Class. Identifier (TID)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: TBA6 Data Item Type: TBA6
skipping to change at page 14, line 15 skipping to change at page 14, line 22
Traffic Classification Identifier (TID): Traffic Classification Identifier (TID):
A 16-bit unsigned integer identifying a traffic classification set A 16-bit unsigned integer identifying a traffic classification set
that has been identified in a Credit Window Traffic Classification that has been identified in a Credit Window Traffic Classification
Data Item, see Section 6.2. Unknown TID values SHOULD be reported Data Item, see Section 6.2. Unknown TID values SHOULD be reported
and result in associated traffic being dropped. and result in associated traffic being dropped.
A router that receives the Credit Window Associate Data Item MUST A router that receives the Credit Window Associate Data Item MUST
locate the traffic classification information indicated by the locate the traffic classification information indicated by the
received TID. If no corresponding information can be located, the received TID. If no corresponding information can be located, the
Data Item MUST be treated as an error as described above. Once the data item MUST be treated as an error as described above. Once the
traffic classification information is located, it MUST be associated traffic classification information is located, it MUST be associated
with the destination and the router MUST ensure that any data plane with the destination and the router MUST ensure that any data plane
state, see Section 4, that is associated with the TID is updated as state, see Section 4, that is associated with the TID is updated as
needed. needed.
6.4. Credit Window Credit Grant 6.4. Credit Window Credit Grant
The Credit Window Credit Grant data item is used by a modem to The Credit Window Credit Grant data item is used by a modem to
provide credits to a router. One or more Credit Window Grant Data provide credits to a router. One or more Credit Window Grant Data
Items MAY be carried in the DLEP Destination Up, Destination Announce Items MAY be carried in the DLEP Destination Up, Destination Announce
Response, Destination Update, and Credit Control Messages. Multiple Response, Destination Update, Credit Control Messages, and Credit
Credit Window Grant Data Items in a single message are used to Control Response Messages. Multiple Credit Window Grant Data Items
indicate different credit values for different credit windows. In in a single message are used to indicate different credit values for
all message types, this data item provides an additional number of different credit windows. In all message types, this data item
octets to be added to the indicated credit window. Credit window are provides an additional number of octets to be added to the indicated
identified via using using CID values that have been previously been credit window. Credit window are identified via using using CID
sent by the modem or are listed in a Credit Window Initialization values that have been previously been sent by the modem or are listed
Data Item carried in the same messages as the Data Item. in a Credit Window Initialization Data Item carried in the same
messages as the data item.
The format of the Credit Window Grant Data Item is: The format of the Credit Window Grant Data Item is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length (12) | | Data Item Type | Length (12) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Window Identifier (CID)| Reserved | | Credit Window Identifier (CID)| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 15, line 19 skipping to change at page 15, line 36
Credit Window Identifier (CID): Credit Window Identifier (CID):
A 16-bit unsigned integer identifying a credit window that has A 16-bit unsigned integer identifying a credit window that has
been identified in a Credit Window Initialization Data Item, see been identified in a Credit Window Initialization Data Item, see
Section 6.1. Unknown CID values SHOULD be reported and ignored. Section 6.1. Unknown CID values SHOULD be reported and ignored.
Additional Credit: Additional Credit:
A 64-bit unsigned integer representing the credits, in octets, to A 64-bit unsigned integer representing the credits, in octets, to
be added to the Credit Window. This value includes MAC headers as be added to the Credit Window. This value includes MAC headers as
seen on the link between the modem and router. seen on the link between the modem and router. A value of zero
indicates that no additional credits are being provided.
When receiving this data item, a router MUST identify the credit When receiving this data item, a router MUST identify the credit
window indicated by the CID. If the CID is not known to the router, window indicated by the CID. If the CID is not known to the router,
it SHOULD report or log this information and discard the Data Item. it SHOULD report or log this information and discard the Data Item.
It is important to note that while this data item can be received in It is important to note that while this data item can be received in
a destination specific message, credit windows are managed a destination specific message, credit windows are managed
independently from the destination identified in the message carrying independently from the destination identified in the message carrying
this Data Item, and the indicated CID MAY even be disjoint from the this Data Item, and the indicated CID MAY even be disjoint from the
identified destination. identified destination.
Once the credit window is identified, the credit window size MUST be Once the credit window is identified, the credit window size MUST be
increased by the value contained in the Additional Credits field. If increased by the value contained in the Additional Credits field. If
the increase results in a window overflow, i.e., the size of the the increase results in a window overflow, i.e., the size of the
credit window after the increase is smaller than the original credit credit window after the increase is smaller than the original credit
window size, the Credit Window must be set to its maximum window size, the Credit Window must be set to its maximum
(0xFFFFFFFFFFFFFFFF). (0xFFFFFFFFFFFFFFFF).
Independent of the received message, the receiving router MUST send a No response is sent by the router to a modem after processing a
Credit Window Window Status data item or items reflecting the Credit Window Grant Data Item received in a Credit Control Response
resulting Credit Window value of the updated credit window. When the Message. In other cases, the receiving router MUST send a Credit
Credit Grant data item is received in a Destination Up Message, the Window Status data item or items reflecting the resulting Credit
Credit Window Window Status data item(s) MUST be sent in the Window value of the updated credit window. When the Credit Grant
corresponding Destination Up Response Message. In all other cases, a data item is received in a Destination Up Message, the Credit Window
Credit Control Message MUST be sent. Status data item(s) MUST be sent in the corresponding Destination Up
Response Message. Otherwise, a Credit Control Message MUST be sent.
6.5. Credit Window Status 6.5. Credit Window Status
The Credit Window Status data item is used by a router to report the The Credit Window Status data item is used by a router to report the
current credit window size to its peer modem. One or more Credit current credit window size to its peer modem. One or more Credit
Window Status data items MAY be carried in a Destination Up Response Window Status data items MAY be carried in a Destination Up Response
Message or a Credit Control Response Message. As discussed above, Message or a Credit Control Response Message. As discussed above,
the Destination Up Response Message is used when the data item is the Destination Up Response Message is used when the data item is
sent in response to a Destination Up Message, and the Credit Control sent in response to a Destination Up Message, and the Credit Control
Response Message is sent in response to a Credit Control Message. Response Message is sent in response to a Credit Control Message.
Multiple Credit Window Window Status data items in a single message Multiple Credit Window Status data items in a single message are used
are used to indicated different sizes of different credit windows. to indicated different sizes of different credit windows. Similar to
Similar to the Credit Window Grant, credit windows are identified the Credit Window Grant, credit windows are identified using CID
using CID values that have been previously been sent by the modem. values that have been previously been sent by the modem.
The format of the Credit Window Window Status Data Item is: The format of the Credit Window Status Data Item is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length (12) | | Data Item Type | Length (12) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Window Identifier (CID)| Reserved | | Credit Window Identifier (CID)| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Window Size : | Credit Window Size :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 16, line 49 skipping to change at page 17, line 20
Credit Window Size: Credit Window Size:
A 64-bit unsigned integer, indicating the current number of A 64-bit unsigned integer, indicating the current number of
credits, in octets, available for the router to send to the modem. credits, in octets, available for the router to send to the modem.
This is referred to as the Modem Receive Window in This is referred to as the Modem Receive Window in
[I-D.ietf-manet-credit-window]. [I-D.ietf-manet-credit-window].
When receiving this data item, a modem MUST identify the credit When receiving this data item, a modem MUST identify the credit
window indicated by the CID. If the CID is not known to the modem, window indicated by the CID. If the CID is not known to the modem,
it SHOULD report or log this information and discard the Data Item. it SHOULD report or log this information and discard the data item.
As with the Credit Window Grant Data Item, the CID MAY be unrelated As with the Credit Window Grant Data Item, the CID MAY be unrelated
to the Destination indicated in the message carrying the Data Item. to the Destination indicated in the message carrying the data item.
Once the credit window is identified, the modem SHOULD check the Once the credit window is identified, the modem SHOULD check the
received Credit Window Size field value against the outstanding received Credit Window Size field value against the outstanding
credit window's available credits at the time the most Credit Window credit window's available credits at the time the most Credit Window
Initialization or Grant data item associated with the indicated CID Initialization or Grant data item associated with the indicated CID
was sent. If the values significantly differ, i.e., greater than can was sent. If the values significantly differ, i.e., greater than can
be accounted for based on observed data frames, then the modem SHOULD be accounted for based on observed data frames, then the modem SHOULD
send a Credit Window Initialization Data Item to reset the associated send a Credit Window Initialization Data Item to reset the associated
credit window size to the modem's current view of the available credit window size to the modem's current view of the available
credits. As defined above, Credit Window Initialization Data Items credits. As defined above, Credit Window Initialization Data Items
are sent in Session Update Messages. When multiple data items need are sent in Session Update Messages. When multiple data items need
to be sent, they SHOULD be combined into a single message when to be sent, they SHOULD be combined into a single message when
possible. Alternatively, and also in cases where there are small possible. Alternatively, and also in cases where there are small
differences, the modem MAY adjust the values sent in Credit Window differences, the modem MAY adjust the values sent in Credit Window
Grant data items to account for the reported Credit Window. Grant data items to account for the reported Credit Window.
6.6. Credit Window Request 6.6. Credit Window Request
The Credit Window Request Data Item data item is used by a router to The Credit Window Request Data Item is used by a router to request
request additional credits for particular credit windows. Credit additional credits for particular credit windows. Credit Window
Window Request Data Items are carried in Credit Control Messages, and Request Data Items are carried in Credit Control Messages, and one or
only one Credit Window Request data item SHOULD be present in a more Credit Window Request Data Items MAY be present in a message.
message.
Credit windows identified using a CID as defined above in Credit windows identified using a CID as defined above in
Section 6.1. Multiple CIDs MAY be present to allow for the case Section 6.1. Multiple CIDs MAY be present to allow for the case
where the router identifies that credits are needed in multiple where the router identifies that credits are needed in multiple
credit windows. The special CID value of 0xFFFFFFFF is used to credit windows. The special CID value of 0xFFFFFFFF is used to
indicate that a credit request is being made across all queues. indicate that a credit request is being made across all queues.
The format of the Credit Window Request Data Item is: The format of the Credit Window Request Data Item is:
0 1 2 3 0 1 2 3
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