draft-ietf-mpls-cr-ldp-03.txt   draft-ietf-mpls-cr-ldp-04.txt 
MPLS Working Group Bilel Jamoussi, Editor MPLS Working Group Bilel Jamoussi, Editor
Internet Draft Nortel Networks Corp. Internet Draft Nortel Networks Corp.
Expiration Date: March 2000 Expiration Date: January 2001
September 1999
O. Aboul-Magd, L. Andersson, P. Ashwood-Smith,
F. Hellstrand, K. Sundell, Nortel Networks Corp.
R. Callon, Juniper Networks.
R. Dantu, IPmobile
P. Doolan, T. Worster, Ennovate Networks Corp.
N. Feldman, IBM Corp.
A. Fredette, PhotonEx Corp.
M. Girish, Atoga Systems
E. Gray, Zaffire, Inc.
J. Halpern, Longitude Systems, Inc.
J. Heinanen, Telia Finland
T. Kilty, Newbridge Networks, Inc.
A. Malis, Vivace Networks
P. Vaananen, Nokia Telecommunications
L. Wu, Cisco Systems
July 2000
Constraint-Based LSP Setup using LDP Constraint-Based LSP Setup using LDP
draft-ietf-mpls-cr-ldp-03.txt draft-ietf-mpls-cr-ldp-04.txt
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
skipping to change at line 36 skipping to change at line 54
http://www.ietf.org/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
Abstract Abstract
Label Distribution Protocol (LDP) is defined in [1] for distribution Label Distribution Protocol (LDP) is defined in [1] for distribution
of labels inside one MPLS domain. One of the most important of labels inside one MPLS domain. One of the most important
services that may be offered using MPLS in general and LDP in services that may be offered using MPLS in general and LDP in
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 1 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
particular is support for constraint-based routing of traffic across particular is support for constraint-based routing of traffic across
the routed network. Constraint-based routing offers the opportunity the routed network. Constraint-based routing offers the opportunity
to extend the information used to setup paths beyond what is to extend the information used to setup paths beyond what is
available for the routing protocol. For instance, an LSP can be available for the routing protocol. For instance, an LSP can be
setup based on explicit route constraints, QoS constraints, and setup based on explicit route constraints, QoS constraints, and
other constraints. Constraint-based routing (CR) is a mechanism used other constraints. Constraint-based routing (CR) is a mechanism used
to meet Traffic Engineering requirements that have been proposed by to meet Traffic Engineering requirements that have been proposed by
[2], [3] and [4]. These requirements may be met by extending LDP for [2], [3] and [4]. These requirements may be met by extending LDP for
support of constraint-based routed label switched paths (CR-LSPs). support of constraint-based routed label switched paths (CR-LSPs).
Other uses for CR-LSPs include MPLS-based VPNs. Other uses for CR-LSPs include MPLS-based VPNs [5]. More information
about the applicability of CR-LDP can be found in [6].
This draft specifies mechanisms and TLVs for support of CR-LSPs This draft specifies mechanisms and TLVs for support of CR-LSPs
using LDP. using LDP.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 1 Internet Draft Constraint-Based LSP Setup using LDP September, 1999 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL"
in this document are to be interpreted as described in RFC 2119 [7].
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 2 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
Table of Contents Table of Contents
1. Introduction....................................................3 1. Introduction....................................................4
2. Constraint-based Routing Overview...............................3 2. Constraint-based Routing Overview...............................4
2.1 Strict and Loose Explicit Routes...............................4 2.1 Strict and Loose Explicit Routes...............................5
2.2 Traffic Characteristics........................................4 2.2 Traffic Characteristics........................................5
2.3 Pre-emption....................................................5 2.3 Pre-emption....................................................6
2.4 Route Pinning..................................................5 2.4 Route Pinning..................................................6
2.5 Resource Class.................................................5 2.5 Resource Class.................................................6
3. Solution Overview...............................................6 3. Solution Overview...............................................7
3.1 Required Messages and TLVs.....................................7 3.1 Required Messages and TLVs.....................................8
3.2 Label Request Message..........................................7 3.2 Label Request Message..........................................8
3.3 Label Mapping Message..........................................8 3.3 Label Mapping Message..........................................9
3.4 Notification Message...........................................8 3.4 Notification Message..........................................10
3.5 Release , Withdraw, and Abort Messages.........................9 3.5 Release , Withdraw, and Abort Messages........................10
4. Protocol Specification..........................................9 4. Protocol Specification.........................................10
4.1 Explicit Route TLV (ER-TLV)...................................10 4.1 Explicit Route TLV (ER-TLV)...................................11
4.2 Explicit Route Hop TLV (ER-Hop TLV)...........................10 4.2 Explicit Route Hop TLV (ER-Hop TLV)...........................11
4.3 Traffic Parameters TLV........................................11 4.3 Traffic Parameters TLV........................................12
4.3.1 Semantics...................................................13 4.3.1 Semantics...................................................14
4.3.1.1 Frequency.................................................13 4.3.1.1 Frequency.................................................14
4.3.1.2 Peak Rate.................................................13 4.3.1.2 Peak Rate.................................................14
4.3.1.3 Committed Rate............................................14 4.3.1.3 Committed Rate............................................15
4.3.1.4 Excess Burst Size.........................................14 4.3.1.4 Excess Burst Size.........................................15
4.3.1.5 Peak Rate Token Bucket....................................14 4.3.1.5 Peak Rate Token Bucket....................................15
4.3.1.6 Committed Data Rate Token Bucket..........................14 4.3.1.6 Committed Data Rate Token Bucket..........................15
4.3.1.7 Weight....................................................15 4.3.1.7 Weight....................................................16
4.3.2 Procedures..................................................15 4.3.2 Procedures..................................................16
4.3.2.1 Label Request Message.....................................15 4.3.2.1 Label Request Message.....................................16
4.3.2.2 Label Mapping Message.....................................16 4.3.2.2 Label Mapping Message.....................................17
4.3.2.3 Notification Message......................................16 4.3.2.3 Notification Message......................................17
4.4 Preemption TLV................................................16 4.4 Preemption TLV................................................17
4.5 LSPID TLV.....................................................17 4.5 LSPID TLV.....................................................18
4.6 Resource Class (Color) TLV....................................18 4.6 Resource Class (Color) TLV....................................20
4.7 ER-Hop semantics..............................................19 4.7 ER-Hop semantics..............................................20
4.7.1. ER-Hop 1: The IPv4 prefix..................................19 4.7.1. ER-Hop 1: The IPv4 prefix..................................20
4.7.2. ER-Hop 2: The IPv6 address.................................20 4.7.2. ER-Hop 2: The IPv6 address.................................21
4.7.3. ER-Hop 3: The autonomous system number....................20 4.7.3. ER-Hop 3: The autonomous system number....................22
4.7.4. ER-Hop 4: LSPID............................................21 4.7.4. ER-Hop 4: LSPID............................................22
4.8. Processing of the Explicit Route TLV.........................22 4.8. Processing of the Explicit Route TLV.........................23
4.8.1. Selection of the next hop..................................22 4.8.1. Selection of the next hop..................................23
4.8.2. Adding ER-Hops to the explicit route TLV...................23 4.8.2. Adding ER-Hops to the explicit route TLV...................25
4.9 Route Pinning TLV.............................................24 4.9 Route Pinning TLV.............................................25
4.10 CR-LSP FEC Element...........................................24 4.10 CR-LSP FEC Element...........................................26
4.11 Error subcodes...............................................25 4.11 TLV Type Summary.............................................26
5. Security.......................................................25 4.12 FEC Type Summary.............................................27
6. Acknowledgments................................................25 4.13 Status Code Summary..........................................27
7. Intellectual Property Consideration............................26 5. IANA Considerations............................................27
8. References.....................................................26 5.1 TLV Type Name Space...........................................27
9. Author's Addresses.............................................26 5.2 FEC Type Name Space...........................................27
Appendix A: CR-LSP Establishment Examples.........................29 5.3 Status Code Space.............................................27
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A.1 Strict Explicit Route Example.................................29 6. Security.......................................................28
A.2 Node Groups and Specific Nodes Example........................30 7. Acknowledgments................................................28
Appendix B. QoS Service Examples..................................33 8. Intellectual Property Consideration............................28
B.1 Service Examples..............................................33 9. References.....................................................28
B.2 Establishing CR-LSP Supporting Real-Time Applications.........34 10. Author's Addresses............................................29
B.3 Establishing CR-LSP Supporting Delay Insensitive Applications.35 Appendix A: CR-LSP Establishment Examples.........................31
Appendix C. LSP Modification Using CR-LDP.........................36 A.1 Strict Explicit Route Example.................................31
C.1 Introduction..................................................36 A.2 Node Groups and Specific Nodes Example........................32
C.2 Basic Procedure...............................................37 Appendix B. QoS Service Examples..................................35
C.3 Priority Handling.............................................38 B.1 Service Examples..............................................35
C.4 Modification Failure Case Handling............................39 B.2 Establishing CR-LSP Supporting Real-Time Applications.........36
B.3 Establishing CR-LSP Supporting Delay Insensitive Applications.37
1. Introduction 1. Introduction
The need for constraint-based routing (CR) in MPLS has been explored The need for constraint-based routing (CR) in MPLS has been explored
elsewhere [3], [2], and [4]. Explicit routing is a subset of the elsewhere [3], [2], and [4]. Explicit routing is a subset of the
more general constraint-based routing function. At the MPLS WG more general constraint-based routing function. At the MPLS WG
meeting held during the Washington IETF (December 1997) there was meeting held during the Washington IETF (December 1997) there was
consensus that LDP should support explicit routing of LSPs with consensus that LDP should support explicit routing of LSPs with
provision for indication of associated (forwarding) priority. In provision for indication of associated (forwarding) priority. In
the Chicago meeting (August 1998), a decision was made that support the Chicago meeting (August 1998), a decision was made that support
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Section 2 introduces the various constraints defined in this Section 2 introduces the various constraints defined in this
specification. Section 3 outlines the CR-LDP solution. Section 4 specification. Section 3 outlines the CR-LDP solution. Section 4
defines the TLVs and procedures used to setup constraint-based defines the TLVs and procedures used to setup constraint-based
routed label switched paths. Appendix A provides several examples routed label switched paths. Appendix A provides several examples
of CR-LSP path setup. Appendix B provides Service Definition of CR-LSP path setup. Appendix B provides Service Definition
Examples. Examples.
2. Constraint-based Routing Overview 2. Constraint-based Routing Overview
Constraint-based routing is a mechanism that supports the Traffic Constraint-based routing is a mechanism that supports the Traffic
Engineering requirements defined in [4]. Explicit Routing is a
subset of the more general constraint-based routing where the
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Engineering requirements defined in [4]. Explicit Routing is a
subset of the more general constraint-based routing where the
constraint is the explicit route (ER). Other constraints are defined constraint is the explicit route (ER). Other constraints are defined
to provide a network operator with control over the path taken by an to provide a network operator with control over the path taken by an
LSP. This section is an overview of the various constraints LSP. This section is an overview of the various constraints
supported by this specification. supported by this specification.
2.1 Strict and Loose Explicit Routes
Like any other LSP a CR-LSP is a path through an MPLS network. The Like any other LSP a CR-LSP is a path through an MPLS network. The
difference is that while other paths are setup solely based on difference is that while other paths are setup solely based on
information in routing tables or from a management system, the information in routing tables or from a management system, the
constraint-based route is calculated at one point at the edge of constraint-based route is calculated at one point at the edge of
network based on criteria, including but not limited to routing network based on criteria, including but not limited to routing
information. The intention is that this functionality shall give information. The intention is that this functionality shall give
desired special characteristics to the LSP in order to better desired special characteristics to the LSP in order to better
support the traffic sent over the LSP. The reason for setting up CR- support the traffic sent over the LSP. The reason for setting up CR-
LSPs might be that one wants to assign certain bandwidth or other LSPs might be that one wants to assign certain bandwidth or other
Service Class characteristics to the LSP, or that one wants to make Service Class characteristics to the LSP, or that one wants to make
sure that alternative routes use physically separate paths through sure that alternative routes use physically separate paths through
the network. the network.
2.1 Strict and Loose Explicit Routes
An explicit route is represented in a Label Request Message as a An explicit route is represented in a Label Request Message as a
list of nodes or groups of nodes along the constraint-based route. list of nodes or groups of nodes along the constraint-based route.
When the CR-LSP is established, all or a subset of the nodes in a When the CR-LSP is established, all or a subset of the nodes in a
group may be traversed by the LSP. Certain operations to be group may be traversed by the LSP. Certain operations to be
performed along the path can also be encoded in the constraint-based performed along the path can also be encoded in the constraint-based
route. route.
The capability to specify, in addition to specified nodes, groups of The capability to specify, in addition to specified nodes, groups of
nodes, of which a subset will be traversed by the CR-LSP, allows the nodes, of which a subset will be traversed by the CR-LSP, allows the
system a significant amount of local flexibility in fulfilling a system a significant amount of local flexibility in fulfilling a
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To simplify the discussion, we call each group of nodes an abstract To simplify the discussion, we call each group of nodes an abstract
node. Thus, we can also say that a constraint-based route is a path node. Thus, we can also say that a constraint-based route is a path
including all of the abstract nodes, with the specified operations including all of the abstract nodes, with the specified operations
occurring along that path. occurring along that path.
2.2 Traffic Characteristics 2.2 Traffic Characteristics
The traffic characteristics of a path are described in the Traffic The traffic characteristics of a path are described in the Traffic
Parameters TLV in terms of a peak rate, committed rate, and service Parameters TLV in terms of a peak rate, committed rate, and service
granularity. The peak and committed rates describe the bandwidth granularity. The peak and committed rates describe the bandwidth
constraints of a path while the service granularity can be used to
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constraints of a path while the service granularity can be used to
specify a constraint on the delay variation that the CR-LDP MPLS specify a constraint on the delay variation that the CR-LDP MPLS
domain may introduce to a path's traffic. domain may introduce to a path's traffic.
2.3 Pre-emption 2.3 Pre-emption
CR-LDP signals the resources required by a path on each hop of the CR-LDP signals the resources required by a path on each hop of the
route. If a route with sufficient resources can not be found, route. If a route with sufficient resources can not be found,
existing paths may be rerouted to reallocate resources to the new existing paths may be rerouted to reallocate resources to the new
path. This is the process of path pre-emption. Setup and holding path. This is the process of path pre-emption. Setup and holding
priorities are used to rank existing paths (holding priority) and priorities are used to rank existing paths (holding priority) and
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pre-empt other paths. The exact rules determining bumping are an pre-empt other paths. The exact rules determining bumping are an
aspect of network policy. aspect of network policy.
The allocation of setup and holding priority values to paths is an The allocation of setup and holding priority values to paths is an
aspect of network policy. aspect of network policy.
The setup and holding priority values range from zero (0) to seven The setup and holding priority values range from zero (0) to seven
(7). The value zero (0) is the priority assigned to the most (7). The value zero (0) is the priority assigned to the most
important path. It is referred to as the highest priority. Seven (7) important path. It is referred to as the highest priority. Seven (7)
is the priority for the least important path. The use of default is the priority for the least important path. The use of default
priority values is an aspect of network policy. priority values is an aspect of network policy. The recommended
default value is (4).
The setupPriority of a CR-LSP should not be higher (numerically The setupPriority of a CR-LSP should not be higher (numerically
less) than its holdingPriority since it might bump an LSP and be less) than its holdingPriority since it might bump an LSP and be
bumped by the next _equivalent_ request. bumped by the next _equivalent_ request.
2.4 Route Pinning 2.4 Route Pinning
Route pinning is applicable to segments of an LSP that are loosely Route pinning is applicable to segments of an LSP that are loosely
routed - i.e. those segments which are specified with a next hop routed - i.e. those segments which are specified with a next hop
with the `L' bit set or where the next hop is an _abstract node_. A with the _L_ bit set or where the next hop is an _abstract node_. A
CR-LSP may be setup using route pinning if it is undesirable to CR-LSP may be setup using route pinning if it is undesirable to
change the path used by an LSP even when a better next hop becomes change the path used by an LSP even when a better next hop becomes
available at some LSR along the loosely routed portion of the LSP. available at some LSR along the loosely routed portion of the LSP.
2.5 Resource Class 2.5 Resource Class
The network operator may classify network resources in various ways. The network operator may classify network resources in various ways.
These classes are also known as _colors_ or _administrative groups_. These classes are also known as _colors_ or _administrative groups_.
When a CR-LSP is being established, it's necessary to indicate which When a CR-LSP is being established, it's necessary to indicate which
resource classes the CR-LSP can draw from. resource classes the CR-LSP can draw from.
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3. Solution Overview 3. Solution Overview
CR-LSP over LDP Specification is designed with the following goals: CR-LSP over LDP Specification is designed with the following goals:
1. Meet the requirements outlined in [4] for performing traffic 1. Meet the requirements outlined in [4] for performing traffic
engineering and provide a solid foundation for performing engineering and provide a solid foundation for performing
more general constraint-based routing. more general constraint-based routing.
2. Build on already specified functionality that meets the 2. Build on already specified functionality that meets the
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one or more CR-TLVs in the Label Request Message. This means one or more CR-TLVs in the Label Request Message. This means
that the LSR can still be configured for independent control that the LSR can still be configured for independent control
for LSPs established as a result of dynamic routing. However, for LSPs established as a result of dynamic routing. However,
when a Label Request Message includes one or more of the CR- when a Label Request Message includes one or more of the CR-
TLVs, then ordered control is used to setup the CR-LSP. Note TLVs, then ordered control is used to setup the CR-LSP. Note
that this is also true for the loosely routed parts of a CR- that this is also true for the loosely routed parts of a CR-
LSP. LSP.
- New status codes are defined to handle error notification for - New status codes are defined to handle error notification for
failure of established paths specified in the CR-TLVs. failure of established paths specified in the CR-TLVs.
Optional TLVs are not required in the CR-LDP messages for the Optional TLVs MUST be implemented to be compliant with the protocol.
messages to be compliant with the protocol. Optional parameters MAY However, they are optionally carried in the CR-LDP messages to
be required for a particular operation to work (or work correctly),
however.
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signal certain characteristics of the CR-LSP being established or
modified.
Examples of CR-LSP establishment are given in Appendix A to Examples of CR-LSP establishment are given in Appendix A to
illustrate how the mechanisms described in this draft work. illustrate how the mechanisms described in this draft work.
3.1 Required Messages and TLVs 3.1 Required Messages and TLVs
Any Messages, TLVs, and procedures not defined explicitly in this Any Messages, TLVs, and procedures not defined explicitly in this
document are defined in the LDP Specification [1]. The state document are defined in the LDP Specification [1]. The reader can
transitions, which relate to CR-LDP messages, can be found in [5]. use [8] as an informational document about the state transitions,
which relate to CR-LDP messages.
The following subsections are meant as a cross-reference to the [1] The following subsections are meant as a cross-reference to the [1]
document and indication of additional functionality beyond what's document and indication of additional functionality beyond what's
defined in [1] where necessary. defined in [1] where necessary.
Note that use of the Status TLV is not limited to Notification
messages as specified in Section 3.4.6 of [1]. A message other than
a Notification message may carry a Status TLV as an Optional
Parameter. When a message other than a Notification carries a
Status TLV the U-bit of the Status TLV should be set to 1 to
indicate that the receiver should silently discard the TLV if
unprepared to handle it.
3.2 Label Request Message 3.2 Label Request Message
The Label Request Message is as defined in 3.5.8 of [1] with the The Label Request Message is as defined in 3.5.8 of [1] with the
following modifications (required only if any of the CR-TLVs is following modifications (required only if any of the CR-TLVs is
included in the Label Request Message): included in the Label Request Message):
- Only a single FEC-TLV may be included in the Label Request - The Label Request Message MUST include a single FEC-TLV
Message. The CR-LSP FEC TLV should be used. element. The CR-LSP FEC TLV element SHOULD be used. However,
the other FEC-TLVs defined in [1] MAY be used instead for
certain applications.
- The Optional Parameters TLV includes the definition of any of - The Optional Parameters TLV includes the definition of any of
the Constraint-based TLVs specified in Section 4. the Constraint-based TLVs specified in Section 4.
- The Procedures to handle the Label Request Message are - The Procedures to handle the Label Request Message are
augmented by the procedures for processing of the CR-TLVs as augmented by the procedures for processing of the CR-TLVs as
defined in Section 4. defined in Section 4.
The encoding for the CR-LDP Label Request Message is as follows: The encoding for the CR-LDP Label Request Message is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| Label Request (0x0401) | Message Length | |0| Label Request (0x0401) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID | | Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| FEC TLV | | FEC TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSPID TLV (CR-LDP, mandatory) | | LSPID TLV (CR-LDP, mandatory) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-TLV (CR-LDP, optional) | | ER-TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic TLV (CR-LDP, optional) | | Traffic TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Pinning TLV (CR-LDP, optional) | | Pinning TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Resource Class TLV (CR-LDP, optional) | | Resource Class TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Pre-emption TLV (CR-LDP, optional) | | Pre-emption TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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3.3 Label Mapping Message 3.3 Label Mapping Message
The Label Mapping Message is as defined in 3.5.7 of [1] with the The Label Mapping Message is as defined in 3.5.7 of [1] with the
following modifications: following modifications:
- Only a single Label-TLV may be included in the Label Mapping - The Label Mapping Message MUST include a single Label-TLV.
Message.
- The Label Mapping Message Procedures are limited to downstream - The Label Mapping Message Procedures are limited to downstream
on demand ordered control mode. on demand ordered control mode.
A Mapping message is transmitted by a downstream LSR to an upstream A Mapping message is transmitted by a downstream LSR to an upstream
LSR under one of the following conditions: LSR under one of the following conditions:
1. The LSR is the egress end of the CR-LSP and an upstream 1. The LSR is the egress end of the CR-LSP and an upstream
mapping has been requested. mapping has been requested.
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| Message ID | | Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC TLV | | FEC TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label TLV | | Label TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label Request Message ID TLV | | Label Request Message ID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSPID TLV (CR-LDP, optional) | | LSPID TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Traffic TLV (CR-LDP, optional) | | Traffic TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.4 Notification Message 3.4 Notification Message
The Notification Message is as defined in Section 3.5.1 of [1] and The Notification Message is as defined in Section 3.5.1 of [1] and
the Status TLV encoding is as defined in Section 3.4.6 of [1]. the Status TLV encoding is as defined in Section 3.4.6 of [1].
Establishment of an CR-LSP may fail for a variety of reasons. All Establishment of an CR-LSP may fail for a variety of reasons. All
such failures are considered advisory conditions and they are such failures are considered advisory conditions and they are
signaled by the Notification Message. signaled by the Notification Message.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 8 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
Notification Messages carry Status TLVs to specify events being Notification Messages carry Status TLVs to specify events being
signaled. New status codes are defined in Section 4.11 to signal signaled. New status codes are defined in Section 4.11 to signal
error notifications associated with the establishment of a CR-LSP error notifications associated with the establishment of a CR-LSP
and the processing of the CR-TLV. and the processing of the CR-TLV.
The Notification Message may carry the LSPID TLV of the The Notification Message MAY carry the LSPID TLV of the
corresponding CR-LSP. corresponding CR-LSP.
Notification Messages MUST be forwarded toward the LSR originating Notification Messages MUST be forwarded toward the LSR originating
the Label Request at each hop and at any time that procedures in the Label Request at each hop and at any time that procedures in
this specification - or in [1] - specify sending of a Notification this specification - or in [1] - specify sending of a Notification
Message in response to a Label Request Message. Message in response to a Label Request Message.
The encoding of the notification message is as follows: The encoding of the notification message is as follows:
0 1 2 3 0 1 2 3
skipping to change at line 463 skipping to change at line 505
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.5 Release , Withdraw, and Abort Messages 3.5 Release , Withdraw, and Abort Messages
The Label Release , Label Withdraw, and Label Abort Request Messages The Label Release , Label Withdraw, and Label Abort Request Messages
are used as specified in [1]. These messages may also carry the are used as specified in [1]. These messages may also carry the
LSPID TLV. LSPID TLV.
4. Protocol Specification 4. Protocol Specification
The Label Request Message defined in [1] optionally carries one or The Label Request Message defined in [1] MUST carry the LSPID TLV
more of the optional Constraint-based Routing TLVs (CR-TLVs) defined and MAY carry one or more of the optional Constraint-based Routing
in this section. If needed, other constraints can be supported later TLVs (CR-TLVs) defined in this section. If needed, other constraints
through the definition of new TLVs. In this specification, the can be supported later through the definition of new TLVs. In this
following TLVs are defined: specification, the following TLVs are defined:
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 10 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
- Explicit Route TLV - Explicit Route TLV
- Explicit Route Hop TLV - Explicit Route Hop TLV
- Traffic Parameters TLV - Traffic Parameters TLV
- Preemption TLV - Preemption TLV
- LSPID TLV - LSPID TLV
- Route Pinning TLV - Route Pinning TLV
- Resource Class TLV - Resource Class TLV
- CR-LSP FEC TLV - CR-LSP FEC TLV
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 9 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
4.1 Explicit Route TLV (ER-TLV) 4.1 Explicit Route TLV (ER-TLV)
The ER-TLV is an object that specifies the path to be taken by the The ER-TLV is an object that specifies the path to be taken by the
LSP being established. It is composed of one or more Explicit Route LSP being established. It is composed of one or more Explicit Route
Hop TLVs (ER-Hop TLVs) defined in Section 4.2. Hop TLVs (ER-Hop TLVs) defined in Section 4.2.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| ER-TLV (0x0800) | Length | |0|0| Type = 0x0800 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV 1 | | ER-Hop TLV 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV 2 | | ER-Hop TLV 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ............ ~ ~ ............ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV n | | ER-Hop TLV n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A two-byte field carrying the value of the ER-TLV type whichis A fourteen-bit field carrying the value of the ER-TLV Type =
0x800. 0x0800.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
ER-Hop TLVs ER-Hop TLVs
One or more ER-Hop TLVs defined in Section 4.2. One or more ER-Hop TLVs defined in Section 4.2.
4.2 Explicit Route Hop TLV (ER-Hop TLV) 4.2 Explicit Route Hop TLV (ER-Hop TLV)
The contents of an ER-TLV are a series of variable length ER-Hop The contents of an ER-TLV are a series of variable length ER-Hop
TLVs. TLVs.
A node receiving a label request message including an ER-Hop type A node receiving a label request message including an ER-Hop type
that is not supported should not progress the label request message that is not supported MUST not progress the label request message to
to the downstream LSR and should send back a _No Route_ Notification the downstream LSR and MUST send back a _No Route_ Notification
Message. Message.
Each ER-Hop TLV has the form: Each ER-Hop TLV has the form:
0 1 2 3 0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| ER-Hop-Type | Length | |0|0| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Content // | |L| Content // |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
ER-Hop Type ER-Hop Type
A fourteen-bit field carrying the type of the ER-Hop contents.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 10 Internet Draft Constraint-Based LSP Setup using LDP September, 1999 Currently defined values are:
A fourteen-bit field indicating the type of contents of the ER-
Hop. Currently defined values are:
Value Type Value Type
----- ------------------------ ------ ------------------------
0x801 IPv4 prefix 0x0801 IPv4 prefix
0x802 IPv6 prefix 0x0802 IPv6 prefix
0x803 Autonomous system number 0x0803 Autonomous system number
0x804 LSPID 0x0804 LSPID
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
L bit L bit
The L bit in the ER-Hop is a one-bit attribute. If the L bit The L bit in the ER-Hop is a one-bit attribute. If the L bit
is set, then the value of the attribute is _loose._ Otherwise, is set, then the value of the attribute is _loose._ Otherwise,
the value of the attribute is _strict._ For brevity, we say the value of the attribute is _strict._ For brevity, we say
that if the value of the ER-Hop attribute is loose then it is a that if the value of the ER-Hop attribute is loose then it is a
_loose ER-Hop._ Otherwise, it's a _strict ER-Hop._ Further, _loose ER-Hop._ Otherwise, it's a _strict ER-Hop._ Further,
skipping to change at line 579 skipping to change at line 621
4.3 Traffic Parameters TLV 4.3 Traffic Parameters TLV
The following sections describe the CR-LSP Traffic Parameters. The The following sections describe the CR-LSP Traffic Parameters. The
required characteristics of a CR-LSP are expressed by the Traffic required characteristics of a CR-LSP are expressed by the Traffic
Parameter values. Parameter values.
A Traffic Parameters TLV, is used to signal the Traffic Parameter A Traffic Parameters TLV, is used to signal the Traffic Parameter
values. The Traffic Parameters are defined in the subsequent values. The Traffic Parameters are defined in the subsequent
sections. sections.
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 12 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
The Traffic Parameters TLV contains a Flags field, a Frequency, a The Traffic Parameters TLV contains a Flags field, a Frequency, a
Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS. Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS.
The Traffic Parameters TLV is shown below: The Traffic Parameters TLV is shown below:
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0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Traf. Param. TLV (0x0810)| Length | |0|0| Type = 0x0810 | Length = 24 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Frequency | Reserved | Weight | | Flags | Frequency | Reserved | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Data Rate (PDR) | | Peak Data Rate (PDR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Burst Size (PBS) | | Peak Burst Size (PBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Data Rate (CDR) | | Committed Data Rate (CDR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Burst Size (CBS) | | Committed Burst Size (CBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Excess Burst Size (EBS) | | Excess Burst Size (EBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the ER-TLV type A fourteen-bit field carrying the value of the Traffic
which is 0x810. Parameters TLV Type = 0x0810.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes = 24.
Flags Flags
The Flags field is shown below: The Flags field is shown below:
+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+
| Res |F6|F5|F4|F3|F2|F1| | Res |F6|F5|F4|F3|F2|F1|
+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+
Res - These bits are reserved. Res - These bits are reserved.
Zero on transmission. Zero on transmission.
skipping to change at line 631 skipping to change at line 673
F2 - Corresponds to the PBS. F2 - Corresponds to the PBS.
F3 - Corresponds to the CDR. F3 - Corresponds to the CDR.
F4 - Corresponds to the CBS. F4 - Corresponds to the CBS.
F5 - Corresponds to the EBS. F5 - Corresponds to the EBS.
F6 - Corresponds to the Weight. F6 - Corresponds to the Weight.
Each flag Fi is a Negotiable Flag corresponding to a Traffic Each flag Fi is a Negotiable Flag corresponding to a Traffic
Parameter. The Negotiable Flag value zero denotes NotNegotiable Parameter. The Negotiable Flag value zero denotes NotNegotiable
and value one denotes Negotiable. and value one denotes Negotiable.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 12 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
Frequency Frequency
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 13 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
The Frequency field is coded as an 8 bit unsigned integer with The Frequency field is coded as an 8 bit unsigned integer with
the following code points defined: the following code points defined:
0- Unspecified 0- Unspecified
1- Frequent 1- Frequent
2- VeryFrequent 2- VeryFrequent
3-255 - Reserved 3-255 - Reserved
Reserved - Zero on transmission. Ignored on receipt. Reserved - Zero on transmission. Ignored on receipt.
Weight Weight
skipping to change at line 684 skipping to change at line 727
granularity. granularity.
4.3.1.2 Peak Rate 4.3.1.2 Peak Rate
The Peak Rate defines the maximum rate at which traffic SHOULD be The Peak Rate defines the maximum rate at which traffic SHOULD be
sent to the CR-LSP. The Peak Rate is useful for the purpose of sent to the CR-LSP. The Peak Rate is useful for the purpose of
resource allocation. If resource allocation within the MPLS domain resource allocation. If resource allocation within the MPLS domain
depends on the Peak Rate value then it should be enforced at the depends on the Peak Rate value then it should be enforced at the
ingress to the MPLS domain. ingress to the MPLS domain.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 13 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
The Peak Rate is defined in terms of the two Traffic Parameters PDR The Peak Rate is defined in terms of the two Traffic Parameters PDR
and PBS, see section 4.3.1.5 below. and PBS, see section 4.3.1.5 below.
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 14 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
4.3.1.3 Committed Rate 4.3.1.3 Committed Rate
The Committed Rate defines the rate that the MPLS domain commits to The Committed Rate defines the rate that the MPLS domain commits to
be available to the CR-LSP. be available to the CR-LSP.
The Committed Rate is defined in terms of the two Traffic Parameters The Committed Rate is defined in terms of the two Traffic Parameters
CDR and CBS, see section 4.3.1.6 below. CDR and CBS, see section 4.3.1.6 below.
4.3.1.4 Excess Burst Size 4.3.1.4 Excess Burst Size
skipping to change at line 738 skipping to change at line 781
in excess of the peak rate. in excess of the peak rate.
The actual implementation of an LSR doesn't need to be modeled The actual implementation of an LSR doesn't need to be modeled
according to the above formal token bucket specification. according to the above formal token bucket specification.
4.3.1.6 Committed Data Rate Token Bucket 4.3.1.6 Committed Data Rate Token Bucket
The committed rate of a CR-LSP is specified in terms of a token The committed rate of a CR-LSP is specified in terms of a token
bucket C with rate CDR. The extent by which the offered rate bucket C with rate CDR. The extent by which the offered rate
exceeds the committed rate MAY be measured in terms of another token exceeds the committed rate MAY be measured in terms of another token
bucket E, which also operates at rate CDR. The maximum size of the
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 14 Internet Draft Constraint-Based LSP Setup using LDP September, 1999 Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 15 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
bucket E, which also operates at rate CDR. The maximum size of the
token bucket C is CBS and the maximum size of the token bucket E is token bucket C is CBS and the maximum size of the token bucket E is
EBS. EBS.
The token buckets C and E are initially (at time 0) full, i.e., the The token buckets C and E are initially (at time 0) full, i.e., the
token count Tc(0) = CBS and the token count Te(0) = EBS. token count Tc(0) = CBS and the token count Te(0) = EBS.
Thereafter, the token counts Tc and Te are updated CDR times per Thereafter, the token counts Tc and Te are updated CDR times per
second as follows: second as follows:
- If Tc is less than CBS, Tc is incremented by one, else - If Tc is less than CBS, Tc is incremented by one, else
- if Te is less then EBS, Te is incremented by one, else - if Te is less then EBS, Te is incremented by one, else
skipping to change at line 791 skipping to change at line 834
4.3.2 Procedures 4.3.2 Procedures
4.3.2.1 Label Request Message 4.3.2.1 Label Request Message
If an LSR receives an incorrectly encoded Traffic Parameters TLV in If an LSR receives an incorrectly encoded Traffic Parameters TLV in
which the value of PDR is less than the value of CDR then it MUST which the value of PDR is less than the value of CDR then it MUST
send a Notification Message including the Status code _Traffic send a Notification Message including the Status code _Traffic
Parameters Unavailable_ to the upstream LSR from which it received Parameters Unavailable_ to the upstream LSR from which it received
the erroneous message. the erroneous message.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 15 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
If a Traffic Parameter is indicated as Negotiable in the Label If a Traffic Parameter is indicated as Negotiable in the Label
Request Message by the corresponding Negotiable Flag then an LSR MAY Request Message by the corresponding Negotiable Flag then an LSR MAY
replace the Traffic Parameter value with a smaller value. replace the Traffic Parameter value with a smaller value.
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 16 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
If the Weight is indicated as Negotiable in the Label Request If the Weight is indicated as Negotiable in the Label Request
Message by the corresponding Negotiable Flag then an LSR may replace Message by the corresponding Negotiable Flag then an LSR may replace
the Weight value with a lower value (down to 0). the Weight value with a lower value (down to 0).
If, after possible Traffic Parameter negotiation, an LSR can support If, after possible Traffic Parameter negotiation, an LSR can support
the CR-LSP Traffic Parameters then the LSR MUST reserve the the CR-LSP Traffic Parameters then the LSR MUST reserve the
corresponding resources for the CR-LSP. corresponding resources for the CR-LSP.
If, after possible Traffic Parameter negotiation, an LSR cannot If, after possible Traffic Parameter negotiation, an LSR cannot
support the CR-LSP Traffic Parameters then the LSR MUST send a support the CR-LSP Traffic Parameters then the LSR MUST send a
skipping to change at line 843 skipping to change at line 886
release any resources that it possibly had reserved for the CR-LSP. release any resources that it possibly had reserved for the CR-LSP.
In addition, on receiving a Notification Message from a Downstream In addition, on receiving a Notification Message from a Downstream
LSR that is associated with a Label Request from an upstream LSR, LSR that is associated with a Label Request from an upstream LSR,
the local LSR MUST propagate the Notification message using the the local LSR MUST propagate the Notification message using the
procedures in [1]. procedures in [1].
4.4 Preemption TLV 4.4 Preemption TLV
The defualt value of the setup and holding priorities should be in The defualt value of the setup and holding priorities should be in
the middle of the range (e.g., 4) so that this feature can be turned the middle of the range (e.g., 4) so that this feature can be turned
on gradually in an operational network by increasing or decerasing on gradually in an operational network by increasing or decreasing
the priority starting at the middle of the range. the priority starting at the middle of the range.
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Since the Preemption TLV is an optional TLV, LSPs that are setup
without an explicitly signaled preemption TLV SHOULD be treated as
LSPs with the default setup and holding priorities (e.g., 4).
When an established LSP is preempted, the LSR that initiates the
preemption sends a Withdraw Message upstream and a Release Message
downstream.
When an LSP in the process of being established (outstanding Label
Request without getting a Label Mapping back) is preempted, the LSR
that initiates the preemption, sends a Notification Message upstream
and an Abort Message downstream.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Preemption-TLV (0x0820) | Length | |0|0| Type = 0x0820 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SetPrio | HoldPrio | Reserved | | SetPrio | HoldPrio | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the Preemption-TLV A fourteen-bit field carrying the value of the Preemption-TLV
type which is 0x820. Type = 0x0820.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes = 4.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
SetPrio SetPrio
A SetupPriority of value zero (0) is the priority assigned to A SetupPriority of value zero (0) is the priority assigned to
the most important path. It is referred to as the highest the most important path. It is referred to as the highest
priority. Seven (7) is the priority for the least important priority. Seven (7) is the priority for the least important
path. The higher the setup priority, the more paths CR-LDP can path. The higher the setup priority, the more paths CR-LDP can
bump to set up the path. The default value should be 4. bump to set up the path. The default value should be 4.
skipping to change at line 888 skipping to change at line 944
The higher the holding priority, the less likely it is for CR- The higher the holding priority, the less likely it is for CR-
LDP to reallocate its bandwidth to a new path. LDP to reallocate its bandwidth to a new path.
4.5 LSPID TLV 4.5 LSPID TLV
LSPID is a unique identifier of a CR-LSP within an MPLS network. LSPID is a unique identifier of a CR-LSP within an MPLS network.
The LSPID is composed of the ingress LSR Router ID (or any of its The LSPID is composed of the ingress LSR Router ID (or any of its
own Ipv4 addresses) and a Locally unique CR-LSP ID to that LSR. own Ipv4 addresses) and a Locally unique CR-LSP ID to that LSR.
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 18 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
The LSPID is useful in network management, in CR-LSP repair, and in The LSPID is useful in network management, in CR-LSP repair, and in
using an already established CR-LSP as a hop in an ER-TLV. using an already established CR-LSP as a hop in an ER-TLV.
An _action indicator flag_ is carried in the LSPID TLV. This _action An _action indicator flag_ is carried in the LSPID TLV. This _action
indicator flag_ indicates explicitly the action that should be taken indicator flag_ indicates explicitly the action that should be taken
if the LSP already exists on the LSR receiving the message. if the LSP already exists on the LSR receiving the message.
After a CR-LSP is set up, its bandwidth reservation may need to be After a CR-LSP is set up, its bandwidth reservation may need to be
changed by the network operator, due to the new requirements for the changed by the network operator, due to the new requirements for the
traffic carried on that CR-LSP. The _action indicator flag_ is used traffic carried on that CR-LSP. The _action indicator flag_ is used
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 17 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
indicate the need to modify the bandwidth and possibly other indicate the need to modify the bandwidth and possibly other
parameters of an established CR-LSP without service interruption. parameters of an established CR-LSP without service interruption.
This feature has application in dynamic network resources management This feature has application in dynamic network resources management
where traffic of different priorities and service classes is where traffic of different priorities and service classes is
involved. involved.
The procedure for the code point _modify_ is defined in Appendix C. The procedure for the code point _modify_ is defined in [9]. The
The procedures for other flags are FFS. procedures for other flags are FFS.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| LSPID-TLV (0x0821) | Length | |0|0| Type = 0x0821 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |ActFlg | Local CR-LSP ID | | Reserved |ActFlg | Local CR-LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ingress LSR Router ID | | Ingress LSR Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the LSPID-TLV type A fourteen-bit field carrying the value of the LSPID-TLV
which is 0x821. Type = 0x0821.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes = 4.
ActFlg ActFlg
Action Indicator Flag: A 4-bit field that indicates explicitly Action Indicator Flag: A 4-bit field that indicates explicitly
the action that should be taken if the LSP already exists on the action that should be taken if the LSP already exists on
the LSR receiving the message. A set of indicator code points the LSR receiving the message. A set of indicator code points
is proposed as follows: is proposed as follows:
0000: indicates initial LSP setup 0000: indicates initial LSP setup
0001: indicates modify LSP 0001: indicates modify LSP
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
Local CR-LSP ID Local CR-LSP ID
The Local LSP ID is an identifier of the CR-LSP locally unique The Local LSP ID is an identifier of the CR-LSP locally unique
within the Ingress LSR originating the CR-LSP. within the Ingress LSR originating the CR-LSP.
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 19 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
Ingress LSR Router ID Ingress LSR Router ID
An LSR may use any of its own IPv4 addresses in this field. An LSR may use any of its own IPv4 addresses in this field.
4.6 Resource Class (Color) TLV 4.6 Resource Class (Color) TLV
The Resource Class as defined in [4] is used to specify which links The Resource Class as defined in [4] is used to specify which links
are acceptable by this CR-LSP. This information allows for the are acceptable by this CR-LSP. This information allows for the
network's topology to be pruned. network's topology to be pruned.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 18 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| ResCls-TLV (0x0822) | Length | |0|0| Type = 0x0822 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RsCls | | RsCls |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
A fourteen-bit field carrying the value of the ResCls-TLV type A fourteen-bit field carrying the value of the ResCls-TLV Type
which is 0x822. = 0x0822.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes = 4.
RsCls RsCls
The Resource Class bit mask indicating which of the 32 The Resource Class bit mask indicating which of the 32
_administrative groups_ or _colors_ of links the CR-LSP can _administrative groups_ or _colors_ of links the CR-LSP can
traverse. traverse.
4.7 ER-Hop semantics 4.7 ER-Hop semantics
4.7.1. ER-Hop 1: The IPv4 prefix 4.7.1. ER-Hop 1: The IPv4 prefix
The abstract node represented by this ER-Hop is the set of nodes, The abstract node represented by this ER-Hop is the set of nodes,
which have an IP address, which lies within this prefix. Note that which have an IP address, which lies within this prefix. Note that
a prefix length of 32 indicates a single IPv4 node. a prefix length of 32 indicates a single IPv4 node.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| 0x801 | Length | |0|0| Type = 0x0801 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | PreLen | |L| Reserved | PreLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address (4 bytes) | | IPv4 Address (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
IPv4 Address 0x801 A fourteen-bit field carrying the value of the ER-Hop 1, IPv4
Address, Type = 0x0801
Length Length
Specifies the length of the value field in bytes.
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 20 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
Specifies the length of the value field in bytes = 8.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
PreLen PreLen
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 19 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
Prefix Length 1-32 Prefix Length 1-32
IP Address IP Address
A four-byte field indicating the IP Address. A four-byte field indicating the IP Address.
4.7.2. ER-Hop 2: The IPv6 address 4.7.2. ER-Hop 2: The IPv6 address
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| 0x802 | Length | |0|0| 0x0802 | Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | PreLen | |L| Reserved | PreLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address | | IPV6 address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
0x802 IPv6 address A fourteen-bit field carrying the value of the ER-Hop 2, IPv6
Address, Type = 0x0802
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes = 20.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
PreLen PreLen
Prefix Length 1-128 Prefix Length 1-128
IPv6 address IPv6 address
A 128-bit unicast host address. A 128-bit unicast host address.
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 21 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
4.7.3. ER-Hop 3: The autonomous system number 4.7.3. ER-Hop 3: The autonomous system number
The abstract node represented by this ER-Hop is the set of nodes The abstract node represented by this ER-Hop is the set of nodes
belonging to the autonomous system. belonging to the autonomous system.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 20 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| 0x803 | Length | |0|0| 0x0803 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | AS Number | |L| Reserved | AS Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
AS Number 0x803 A fourteen-bit field carrying the value of the ER-Hop 3, AS
Number, Type = 0x0803
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes = 4.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
AS Number AS Number
Autonomous System number Autonomous System number
skipping to change at line 1102 skipping to change at line 1160
the next ER-Hop after the loosely specified CR-LSP segment. Use of the next ER-Hop after the loosely specified CR-LSP segment. Use of
the LSPID Hop in this scenario eliminates the need for ER-Hops to the LSPID Hop in this scenario eliminates the need for ER-Hops to
keep the entire remaining ER-TLV at each LSR that is at either keep the entire remaining ER-TLV at each LSR that is at either
(upstream or downstream) end of a loosely specified CR-LSP segment (upstream or downstream) end of a loosely specified CR-LSP segment
as part of its state information. This is due to the fact that the as part of its state information. This is due to the fact that the
upstream LSR needs only to keep the next ER-Hop and the LSPID and upstream LSR needs only to keep the next ER-Hop and the LSPID and
the downstream LSR needs only to keep the LSPID in order for each the downstream LSR needs only to keep the LSPID in order for each
end to be able to recognize that the same LSP is being identified. end to be able to recognize that the same LSP is being identified.
If the LSPID Hop is not the last hop in an ER-TLV, the LSR must If the LSPID Hop is not the last hop in an ER-TLV, the LSR must
forward the remaining ER-TLV in a Label Request message, using the
CR-LSP specified by the LSPID, to the LSR that is the CR-LSP's
egress. That LSR will continue processing of the CR-LSP Label
Request Message. The result is a tunneled, or stacked, CR-LSP.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 21 Internet Draft Constraint-Based LSP Setup using LDP September, 1999 Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 22 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
remove the LSP-ID Hop and forward the remaining ER-TLV in a Label
Request message using an LDP session established with the LSR that
is the specified CR-LSP's egress. That LSR will continue processing
of the CR-LSP Label Request Message. The result is a tunneled, or
stacked, CR-LSP.
To support labels negotiated for tunneled CR-LSP segments, an LDP
session is required [1] between tunnel end points - possibly using
the existing CR-LSP. Use of the existence of the CR-LSP in lieu of
a session, or other possible session-less approaches, is FFS.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| 0x804 | Length | |0|0| 0x0804 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | Local LSPID | |L| Reserved | Local LSPID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ingress LSR Router ID | | Ingress LSR Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
LSPID 0x804 A fourteen-bit field carrying the value of the ER-Hop 4, LSPID,
Type = 0x0804
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes = 8.
L Bit L Bit
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
Local LSPID Local LSPID
A 2 byte field indicating the LSPID which is unique with A 2 byte field indicating the LSPID which is unique with
skipping to change at line 1148 skipping to change at line 1214
4.8. Processing of the Explicit Route TLV 4.8. Processing of the Explicit Route TLV
4.8.1. Selection of the next hop 4.8.1. Selection of the next hop
A Label Request Message containing an explicit route TLV must A Label Request Message containing an explicit route TLV must
determine the next hop for this path. Selection of this next hop determine the next hop for this path. Selection of this next hop
may involve a selection from a set of possible alternatives. The may involve a selection from a set of possible alternatives. The
mechanism for making a selection from this set is implementation mechanism for making a selection from this set is implementation
dependent and is outside of the scope of this specification. dependent and is outside of the scope of this specification.
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 23 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
Selection of particular paths is also outside of the scope of this Selection of particular paths is also outside of the scope of this
specification, but it is assumed that each node will make a best specification, but it is assumed that each node will make a best
effort attempt to determine a loop-free path. Note that such best effort attempt to determine a loop-free path. Note that such best
efforts may be overridden by local policy. efforts may be overridden by local policy.
To determine the next hop for the path, a node performs the To determine the next hop for the path, a node performs the
following steps: following steps:
1. The node receiving the Label Request Message must first 1. The node receiving the Label Request Message must first
evaluate the first ER-Hop. If the L bit is not set in the evaluate the first ER-Hop. If the L bit is not set in the
first ER-Hop and if the node is not part of the abstract node first ER-Hop and if the node is not part of the abstract node
described by the first ER-Hop, it has received the message in described by the first ER-Hop, it has received the message in
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 22 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
error, and should return a _Bad Initial ER-Hop_ error. If the error, and should return a _Bad Initial ER-Hop_ error. If the
L bit is set and the local node is not part of the abstract L bit is set and the local node is not part of the abstract
node described by the first ER-Hop, the node selects a next node described by the first ER-Hop, the node selects a next
hop that is along the path to the abstract node described by hop that is along the path to the abstract node described by
the first ER-Hop. If there is no first ER-Hop, the message is the first ER-Hop. If there is no first ER-Hop, the message is
also in error and the system should return a _Bad Explicit also in error and the system should return a _Bad Explicit
Routing TLV_ error using a Notification Message sent upstream. Routing TLV_ error using a Notification Message sent upstream.
2. If there is no second ER-Hop, this indicates the end of the 2. If there is no second ER-Hop, this indicates the end of the
explicit route. The explicit route TLV should be removed from explicit route. The explicit route TLV should be removed from
skipping to change at line 1204 skipping to change at line 1270
5.a If the second ER-Hop is a strict ER-Hop, then there is 5.a If the second ER-Hop is a strict ER-Hop, then there is
an error and the node should return a _Bad Strict Node_ an error and the node should return a _Bad Strict Node_
error. error.
5.b Otherwise, if the second ER-Hop is a loose ER-Hop, then 5.b Otherwise, if the second ER-Hop is a loose ER-Hop, then
the node selects any next hop that is along the path to the the node selects any next hop that is along the path to the
next abstract node. If no path exists within the MPLS next abstract node. If no path exists within the MPLS
domain, then there is an error, and the node should return a domain, then there is an error, and the node should return a
_Bad loose node_ error. _Bad loose node_ error.
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 24 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
6. Finally, the node replaces the first ER-Hop with any ER-Hop 6. Finally, the node replaces the first ER-Hop with any ER-Hop
that denotes an abstract node containing the next hop. This that denotes an abstract node containing the next hop. This
is necessary so that when the explicit route is received by is necessary so that when the explicit route is received by
the next hop, it will be accepted. the next hop, it will be accepted.
7. Progress the Label Request Message to the next hop. 7. Progress the Label Request Message to the next hop.
4.8.2. Adding ER-Hops to the explicit route TLV 4.8.2. Adding ER-Hops to the explicit route TLV
After selecting a next hop, the node may alter the explicit route in After selecting a next hop, the node may alter the explicit route in
the following ways. the following ways.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 23 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
If, as part of executing the algorithm in section 4.8.1, the If, as part of executing the algorithm in section 4.8.1, the
explicit route TLV is removed, the node may add a new explicit route explicit route TLV is removed, the node may add a new explicit route
TLV. TLV.
Otherwise, if the node is a member of the abstract node for the Otherwise, if the node is a member of the abstract node for the
first ER-Hop, then a series of ER-Hops may be inserted before the first ER-Hop, then a series of ER-Hops may be inserted before the
first ER-Hop or may replace the first ER-Hop. Each ER-Hop in this first ER-Hop or may replace the first ER-Hop. Each ER-Hop in this
series must denote an abstract node that is a subset of the current series must denote an abstract node that is a subset of the current
abstract node. abstract node.
skipping to change at line 1239 skipping to change at line 1305
series of ER-Hops may be inserted prior to the first ER-Hop. series of ER-Hops may be inserted prior to the first ER-Hop.
4.9 Route Pinning TLV 4.9 Route Pinning TLV
Section 2.4 describes the use of route pinning. The encoding of the Section 2.4 describes the use of route pinning. The encoding of the
Route Pinning TLV is as follows: Route Pinning TLV is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| 0x823 | Length | |0|0| Type = 0x0823 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P| Reserved | |P| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
Pinning-TLV type 0x823 A fourteen-bit field carrying the value of the Pinning-TLV
Type = 0x0823
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes = 4.
P Bit P Bit
The P bit is set to 1 to indicate that route pinning is The P bit is set to 1 to indicate that route pinning is
requested. requested.
The P bit is set to 0 to indicate that route pinning is not The P bit is set to 0 to indicate that route pinning is not
requested requested
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 25 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
4.10 CR-LSP FEC Element 4.10 CR-LSP FEC Element
A new FEC element is introduced in this specification to support CR- A new FEC element is introduced in this specification to support CR-
LSPs. This new FEC element does not preclude the use of other FECs LSPs. A FEC TLV containing a FEC of Element type CR-LSP (0x04) is a
elements (Type=0x01, 0x02, 0x03) defined in the LDP spec in CR-LDP CR-LSP FEC TLV. The CR-LSP FEC Element is an opaque FEC to be used
messages. The CR-LDP FEC Element is an opaque FEC to be used only in only in Messages of CR-LSPs.
Messages of CR-LSPs.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 24 Internet Draft Constraint-Based LSP Setup using LDP September, 1999 A single FEC element MUST be included in the Label Request Message.
The FEC Element SHOULD be the CR-LSP FEC Element. However, one of
the other FEC elements (Type=0x01, 0x02, 0x03) defined in [1] MAY be
in CR-LDP messages instead of the CR-LSP FEC Element for certain
applications. A FEC TLV containing a FEC of Element type CR-LSP
(0x04) is a CR-LSP FEC TLV.
FEC Element Type Value FEC Element Type Value
Type name Type name
CR-LSP 0x04 No value; i.e., 0 value octets; CR-LSP 0x04 No value; i.e., 0 value octets;
The CR-LSP FEC TLV encoding is as follows: The CR-LSP FEC TLV encoding is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| FEC(0x0100) | Length | |0|0| Type = 0x0100 | Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CR-LSP (4) | | CR-LSP (4) |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Type Type
FEC TLV type 0x0100 A fourteen-bit field carrying the value of the FEC TLV
Type = 0x0100
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes = 1.
CR-LSP FEC Element Type CR-LSP FEC Element Type
0x04 0x04
4.11 Error subcodes 4.11 TLV Type Summary
In the processing described above, certain errors need to be TLV Type
reported as part of the Notification Message. This section defines -------------------------------------- ----------
the status codes for the errors described in this specification. Explicit Route TLV 0x0800
Ipv4 Prefix ER-Hop TLV 0x0801
Ipv6 Prefix ER-Hop TLV 0x0802
Autonomous System Number ER-Hop TLV 0x0803
LSP-ID ER-Hop TLV 0x0804
Traffic Parameters TLV 0x0810
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 26 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
Preemption TLV 0x0820
LSPID TLV 0x0821
Resource Class TLV 0x0822
Route Pinning TLV 0x0823
4.12 FEC Type Summary
FEC Element TLV Type
-------------------------------------- ----------
CR-LSP FEC Element TLV 0x0100
4.13 Status Code Summary
Status Code Type Status Code Type
-------------------------------------- ---------- -------------------------------------- ----------
Bad Explicit Routing TLV Error 0x44000001 Bad Explicit Routing TLV Error 0x44000001
Bad Strict Node Error 0x44000002 Bad Strict Node Error 0x44000002
Bad Loose Node Error 0x44000003 Bad Loose Node Error 0x44000003
Bad Initial ER-Hop Error 0x44000004 Bad Initial ER-Hop Error 0x44000004
Resource Unavailable 0x44000005 Resource Unavailable 0x44000005
Traffic Parameters Unavailable 0x44000006 Traffic Parameters Unavailable 0x44000006
Setup Abort (Label Request Aborted in [1]) 0x04000015 LSP Preempted 0x44000007
Modify Request Not Supported 0x44000008 Modify Request Not Supported 0x44000008
Setup Abort (Label Request Aborted in [1]) 0x04000015
5. Security 5. IANA Considerations
Pre-emption has to be controlled by the MPLS domain. CR-LDP defines the following name spaces, which require management:
Resource reservation requires the LSRs to have an LSP admission - TLV types.
control function. - FEC types.
- Status codes.
Traffic Engineered LSPs can bypass normal routing. The following sections provide guidelines for managing these name
spaces.
6. Acknowledgments 5.1 TLV Type Name Space
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 25 Internet Draft Constraint-Based LSP Setup using LDP September, 1999 TLV types in the range 0x0800 - 0x08FF are allocated to CR-LDP base
protocol. Following the policies outlined in [IANA], TLV types in
this range are allocated through an IETF Consensus action.
5.2 FEC Type Name Space
FEC Type 100 is allocated to CR-LDP.
5.3 Status Code Space
The range for Status Codes is 0x44000000 - 0x440000FF.
Following the policies outlined in [IANA], Status Codes in the range
0x44000000 - 0x440000FF are allocated through an IETF Consensus
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 27 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
action.
6. Security
CR-LDP inherits the same security mechanism described in Section 4.0
of [1] to protect against the introduction of spoofed TCP segments
into LDP session connection streams.
7. Acknowledgments
The messages used to signal the CR-LSP setup are based on the work The messages used to signal the CR-LSP setup are based on the work
done by the [1] team. done by the [1] team.
The authors would also like to acknowledge the careful review and The authors would also like to acknowledge the careful review and
comments of Ken Hayward, Greg Wright, Geetha Brown, Brian Williams, comments of Ken Hayward, Greg Wright, Geetha Brown, Brian Williams,
Paul Beaubien, Matthew Yuen, Liam Casey, Ankur Anand, Adrian Farrel. Paul Beaubien, Matthew Yuen, Liam Casey, Ankur Anand, Adrian Farrel.
7. Intellectual Property Consideration 8. Intellectual Property Consideration
The IETF has been notified of intellectual property rights claimed The IETF has been notified of intellectual property rights claimed
in regard to some or all of the specification contained in this in regard to some or all of the specification contained in this
document. For more information consult the online list of claimed document. For more information consult the online list of claimed
rights. rights.
8. References 9. References
1 Andersson et al, "Label Distribution Protocol Specification" 1 Andersson et al, "Label Distribution Protocol Specification"
work in progress (draft-ietf-mpls-ldp-05), June 1999. work in progress (draft-ietf-mpls-ldp-08), June 2000.
2 Callon et al, "Framework for Multiprotocol Label Switching", 2 Callon et al, "Framework for Multiprotocol Label Switching",
work in progress (draft-ietf-mpls-framework-05), September 1999. work in progress (draft-ietf-mpls-framework-05), September 1999.
3 Rosen et al, "Multiprotocol Label Switching Architecture", 3 Rosen et al, "Multiprotocol Label Switching Architecture",
work in progress (draft-ietf-mpls-arch-06), September 1999. work in progress (draft-ietf-mpls-arch-06), August 1999.
4 Awduche et al, "Requirements for Traffic Engineering Over 4 Awduche et al, "Requirements for Traffic Engineering Over
MPLS", RFC 2702, September 1999. MPLS", RFC 2702, September 1999.
5 L. Wu, et. al., "LDP State Machine" work in progress 5 B. Gleeson, et. al., "A Framework for IP Based Virtual Private
(draft-ietf-mpls-ldp-state-00), Feb 1999. Networks", RFC 2764, February 2000.
9. Author's Addresses 6 B. Jamoussi, et. al., _Applicability Statement for CR-LDP_, work
in progress, (draft-ietf-mpls-crldp-applic-01), June 2000.
7 S. Bradner, "Key words for use in RFCs to Indicate Requirement
Levels_, RFC 2119, March 1997.
8 L. Wu, et. al., "LDP State Machine", work in progress,
(draft-ietf-mpls-ldp-state-03), January 2000.
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 28 Internet Draft Constraint-Based LSP Setup using LDP July, 2000
9 J. Ash, et. al., "LSP Modification Using CR-LDP", work in
progress, (draft-ietf-mpls-crlsp-modify-01), February 2000.
10. Author's Addresses
Osama S. Aboul-Magd Loa Andersson Osama S. Aboul-Magd Loa Andersson
Nortel Networks Nortel Networks Nortel Networks Nortel Networks
P O Box 3511 Station C S:t Eriksgatan 115 P O Box 3511 Station C S:t Eriksgatan 115
Ottawa, ON K1Y 4H7 PO Box 6701 Ottawa, ON K1Y 4H7 PO Box 6701
Canada 113 85 Stockholm Canada 113 85 Stockholm
Phone: +1 613 763-5827 Tel: +46 8 508 835 00 Phone: +1 613 763-5827 Tel: +46 8 508 835 00
Osama@nortelnetworks.com Fax: +46 8 508 835 01 Osama@nortelnetworks.com Fax: +46 8 508 835 01
Loa_andersson@nortelnetworks.com Loa_andersson@nortelnetworks.com
Peter Ashwood-Smith Ross Callon Peter Ashwood-Smith Ross Callon
Nortel Networks IronBridge Networks Nortel Networks Juniper Networks
P O Box 3511 Station C 55 Hayden Avenue, P O Box 3511 Station C 1194 North Mathilda Avenue,
Ottawa, ON K1Y 4H7 Lexington, MA 02173 Ottawa, ON K1Y 4H7 Sunnyvale, CA 94089
Canada Phone: +1-781-402-8017 Canada 978-692-6724
Phone: +1 613 763-4534 Rcallon@ironbridgenetworks.com Phone: +1 613 763-4534 rcallon@juniper.net
Petera@nortelnetworks.com Petera@nortelnetworks.com
Ram Dantu Paul Doolan Ram Dantu Paul Doolan
Alcatel USA Inc. Ennovate Networks IPmobile Ennovate Networks
1651 North Glenville, Suite 216 330 Codman Hill Rd
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 26 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Richardson, TX 75081 Marlborough MA 01719
+1-972-234-6070 extension 211 Phone: 978-263-2002
IP Competence Center 330 Codman Hill Rd rdantu@ipmobile.com Pdoolan@ennovatenetworks.com
1201 E. Campbell Road.,446-315 Marlborough MA 01719
Richadson, TX USA., 75081-2206 Phone: 978-263-2002
Phone: 972 996 2938 Pdoolan@ennovatenetworks.com
Fax: 972 996 5902
Ram.dantu@alcatel.com
Nancy Feldman Andre Fredette Nancy Feldman Andre Fredette
IBM Corp. Nortel Networks IBM Corp. PhotonEx Corporation
17 Skyline Drive 600 Technology Park Drive 17 Skyline Drive 135 South Road
Hawthorne NY 10532 Billerica, MA 01821 Hawthorne NY 10532 Bedford, MA 01730
Phone: 914-784-3254 978-288-8524 Phone: 914-784-3254 email: fredette@photonex.com
Nkf@us.ibm.com Fredette@nortelnetworks.com Nkf@us.ibm.com phone: 781-275-8500
Eric Gray Joel M. Halpern Eric Gray Joel M. Halpern
Lucent Technologies, Inc Institutional Venture Partners Zaffire, Inc Longitude Systems, Inc.
1600 Osgood St. 650-926-5633 2630 Orchard Parkway, 1319 Shepard Road
North Andover, MA 01847 Joel@mcquillan.com San Jose, CA 95134-2020 Sterling, VA 20164
Phone: 603-659-3386 Phone: 408-894-7362 703-433-0808 x207
Ewgray@lucent.com egray@zaffire.com joel@longsys.com
Juha Heinanen Fiffi Hellstrand Juha Heinanen Fiffi Hellstrand
Telia Finland, Inc. Ericsson Telecom AB Telia Finland, Inc. Nortel Networks
Myyrmaentie 2 S-126 25 STOCKHOLM Myyrmaentie 2 S:t Eriksgatan 115
01600 VANTAA Sweden 01600 VANTAA PO Box 6701, 113 85 Stockholm
Finland Tel: +46 8 719 4933 Finland Sweden
Tel: +358 41 500 4808 Etxfiff@etxb.ericsson.se Tel: +358 41 500 4808 +46705593687
Jh@telia.fi Jh@telia.fi fiffi@nortelnetworks.com
Jamoussi, et. al. draft-ietf-mpls-crldp-04.txt 29 Internet Draft Constraint-Based LSP Setup using LDP July 2000
Bilel Jamoussi Timothy E. Kilty Bilel Jamoussi Timothy E. Kilty
Nortel Networks Corp. Northchurch Communications Nortel Networks Corp. Newbridge Networks, Inc.
600 Technology Park Drive 5 Corporate Drive, 600 Technology Park Drive 5 Corporate Drive
Billerica, MA 01821 Andover, MA 018110 Billerica, MA 01821 Andover, MA 01810
USA phone: 978 691-4656 USA USA
Phone: +1 978 288-4506 Tkilty@northc.com Phone: +1 978 288-4506 phone: 978 691-4656
Jamoussi@nortelnetworks.com Jamoussi@nortelnetworks.com tkilty@northchurch.net
Andrew G. Malis Muckai K Girish Andrew G. Malis Muckai K Girish
Ascend Communications, Inc. SBC Technology Resources, Vivace Networks Atoga Systems
1 Robbins Road 4698 Willow Road 2730 Orchard Parkway 49026 Milmont Drive
Westford, MA 01886 Pleasanton, CA 94588 San Jose, CA 95134 Fremont, CA 94538
Phone: 978 952-7414 Phone: (925) 598-1263 Andy.Malis@vivacenetworks.com E-mail: muckai@atoga.com
fax: 978 392-2074 Fax: (925) 598-1321 Tel: +1 408 383 7223
Malis@ascend.com Mgirish@tri.sbc.com Fax: +1 408 904 4748
Kenneth Sundell Pasi Vaananen Kenneth Sundell Pasi Vaananen
Nortel Networks Nokia Telecommunications Nortel Networks Nokia Telecommunications
S:t Eriksgatan 115 3 Burlington Woods Drive, S:t Eriksgatan 115 3 Burlington Woods Drive,
PO Box 6701 Burlington, MA 01803 PO Box 6701 Burlington, MA 01803
113 85 Stockholm Phone: +1-781-238-4981 113 85 Stockholm Phone: +1-781-238-4981
Tel: +46 8 508 835 00 Pasi.vaanenen@ntc.nokia.com Tel: +46 8 508 835 00 pasi.vaananen@nokia.com
Fax: +46 8 508 835 01 Fax: +46 8 508 835 01
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 27 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Ksundell@nortelnetworks.com Ksundell@nortelnetworks.com
Tom Worster Liwen Wu Tom Worster Liwen Wu
Nokia Alcatel U.S.A Ennovate Networks Cisco Systems
3 Burlington Woods Dr. 44983 Knoll Square 60 Codman Hill Rd 250 Apollo Drive
Suite 250 Ashburn, Va. 20147 Boxborough Chelmsford, MA. 01824
Burlington MA 01803 USA Phone: (703) 724-2619 MA 01719 Tel: 978-244-3087.
+1 617 247 2624 FAX: (703) 724-2005 tworster@ennovatenetworks.com liwwu@cisco.com
Tom.worster@nokia.com Liwen.wu@and.alcatel.com
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 28 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 30 Internet Draft Constraint-Based LSP Setup using LDP July 2000
Appendix A: CR-LSP Establishment Examples Appendix A: CR-LSP Establishment Examples
A.1 Strict Explicit Route Example A.1 Strict Explicit Route Example
This appendix provides an example for the setup of a strictly routed This appendix provides an example for the setup of a strictly routed
CR-LSP. In this example, a specific node represents each abstract CR-LSP. In this example, a specific node represents each abstract
node. node.
The sample network used here is a four node network with two edge The sample network used here is a four node network with two edge
skipping to change at line 1498 skipping to change at line 1627
Also, LSR2 is not a member of the abstract node described by the Also, LSR2 is not a member of the abstract node described by the
first ER-Hop <b>. first ER-Hop <b>.
Finally, the first ER-Hop <b> is a strict hop. Finally, the first ER-Hop <b> is a strict hop.
Therefore, processing section 4.8.2 does not result in the insertion Therefore, processing section 4.8.2 does not result in the insertion
of new ER-Hops. The selection of the next hop has been already done of new ER-Hops. The selection of the next hop has been already done
is step 4 of Section 4.8.1 and the processing of the ER-TLV is is step 4 of Section 4.8.1 and the processing of the ER-TLV is
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 29 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 31 Internet Draft Constraint-Based LSP Setup using LDP July 2000
completed at LSR2. In this case, the Label Request Message including completed at LSR2. In this case, the Label Request Message including
the ER-TLV <b, c> is progressed by LSR2 to LSR3. the ER-TLV <b, c> is progressed by LSR2 to LSR3.
At LSR3, a similar processing to the ER-TLV takes place except that At LSR3, a similar processing to the ER-TLV takes place except that
the incoming ER-TLV = <b, c> and the outgoing ER-TLV is <c>. the incoming ER-TLV = <b, c> and the outgoing ER-TLV is <c>.
At LSR4, the following processing of section 4.8.1 takes place: At LSR4, the following processing of section 4.8.1 takes place:
1) The node LSR4 is part of the abstract node described by the 1) The node LSR4 is part of the abstract node described by the
skipping to change at line 1553 skipping to change at line 1682
The ingress LSR uses information provided by the management system The ingress LSR uses information provided by the management system
or the application and possibly also information from the routing or the application and possibly also information from the routing
database to calculate the explicit route and to create the Label database to calculate the explicit route and to create the Label
Request Message. Request Message.
The Label request message carries together with other necessary The Label request message carries together with other necessary
information an ER-TLV defining the explicitly routed path. In our information an ER-TLV defining the explicitly routed path. In our
example the list of hops in the ER-Hop TLV is supposed to contain an example the list of hops in the ER-Hop TLV is supposed to contain an
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 30 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 32 Internet Draft Constraint-Based LSP Setup using LDP July 2000
abstract node representing a group of nodes, an abstract node abstract node representing a group of nodes, an abstract node
representing a specific node, another abstract node representing a representing a specific node, another abstract node representing a
group of nodes, and an abstract node representing a specific egress group of nodes, and an abstract node representing a specific egress
point. point.
In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B} In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B}
The ER-TLV contains four ER-Hop TLVs: The ER-TLV contains four ER-Hop TLVs:
1. An ER-Hop TLV that specifies a group of LSR valid for the 1. An ER-Hop TLV that specifies a group of LSR valid for the
skipping to change at line 1606 skipping to change at line 1735
is not the specific node (A) in the second ER-Hop TLV. is not the specific node (A) in the second ER-Hop TLV.
Further it realizes that the specific node (A) is one of its Further it realizes that the specific node (A) is one of its
next hops. next hops.
5. It removes the first ER-Hop TLVs and sends a Label Request 5. It removes the first ER-Hop TLVs and sends a Label Request
Message to the specific node (A). Message to the specific node (A).
6. The specific node (A) recognizes itself in the first ER-Hop 6. The specific node (A) recognizes itself in the first ER-Hop
TLV. Removes the specific ER-Hop TLV. TLV. Removes the specific ER-Hop TLV.
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 31 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 33 Internet Draft Constraint-Based LSP Setup using LDP July 2000
7. It sends a Label Request Message to a node that is a member 7. It sends a Label Request Message to a node that is a member
of the group (Group 2) indicated in the ER-Hop TLV. of the group (Group 2) indicated in the ER-Hop TLV.
8. The node that receives the message identifies itself as part 8. The node that receives the message identifies itself as part
of the group indicated in the first ER-Hop TLV, further it of the group indicated in the first ER-Hop TLV, further it
realizes that the specific egress node (B) is one of its realizes that the specific egress node (B) is one of its
next hops. next hops.
9. It sends a Label Request Message to the specific egress node 9. It sends a Label Request Message to the specific egress node
skipping to change at line 1620 skipping to change at line 1749
8. The node that receives the message identifies itself as part 8. The node that receives the message identifies itself as part
of the group indicated in the first ER-Hop TLV, further it of the group indicated in the first ER-Hop TLV, further it
realizes that the specific egress node (B) is one of its realizes that the specific egress node (B) is one of its
next hops. next hops.
9. It sends a Label Request Message to the specific egress node 9. It sends a Label Request Message to the specific egress node
(B). (B).
10.The specific egress node (B) recognizes itself as the egress 10.The specific egress node (B) recognizes itself as the egress
for the CR-LSP, it returns a Label Mapping Message, that for the CR-LSP, it returns a Label Mapping Message, that
will traverse the same path as the Label Request Message in will traverse the same path as the Label Request Message in
the opposite direction. the opposite direction.
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 32 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 34 Internet Draft Constraint-Based LSP Setup using LDP July 2000
Appendix B. QoS Service Examples Appendix B. QoS Service Examples
B.1 Service Examples B.1 Service Examples
Construction of an end-to-end service is the result of the rules Construction of an end-to-end service is the result of the rules
enforced at the edge and the treatment that packets receive at the enforced at the edge and the treatment that packets receive at the
network nodes. The rules define the traffic conditioning actions network nodes. The rules define the traffic conditioning actions
that are implemented at the edge and they include policing with that are implemented at the edge and they include policing with
pass, mark, and drop capabilities. The edge rules are expected tobe pass, mark, and drop capabilities. The edge rules are expected tobe
skipping to change at line 1680 skipping to change at line 1808
ATM-VBR.3(nrt) PCR CDVT SCR MBS 0 Unspecified drop>PCR ATM-VBR.3(nrt) PCR CDVT SCR MBS 0 Unspecified drop>PCR
mark>SCR,MBS mark>SCR,MBS
ATM-UBR PCR CDVT - - 0 Unspecified drop>PCR ATM-UBR PCR CDVT - - 0 Unspecified drop>PCR
ATM-GFR.1 PCR CDVT MCR MBS 0 Unspecified drop>PCR ATM-GFR.1 PCR CDVT MCR MBS 0 Unspecified drop>PCR
ATM-GFR.2 PCR CDVT MCR MBS 0 Unspecified drop>PCR ATM-GFR.2 PCR CDVT MCR MBS 0 Unspecified drop>PCR
mark>MCR,MFS mark>MCR,MFS
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 33 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 35 Internet Draft Constraint-Based LSP Setup using LDP July 2000
int-serv-CL p m r b 0 Frequent drop>p int-serv-CL p m r b 0 Frequent drop>p
drop>r,b drop>r,b
S= User specified S= User specified
In the above table, the DS refers to a delay sensitive service where In the above table, the DS refers to a delay sensitive service where
the network commits to deliver with high probability user datagrams the network commits to deliver with high probability user datagrams
at a rate of PDR with minimum delay and delay requirements. at a rate of PDR with minimum delay and delay requirements.
Datagrams in excess of PDR will be discarded. Datagrams in excess of PDR will be discarded.
skipping to change at line 1732 skipping to change at line 1860
the edge. The specification of those actions is expected to be a the edge. The specification of those actions is expected to be a
part of the service level agreement (SLA) negotiation and is not part of the service level agreement (SLA) negotiation and is not
included in the signaling protocol. For DS service, the edge action included in the signaling protocol. For DS service, the edge action
is to drop packets that exceed the PDR and the PBS specifications. is to drop packets that exceed the PDR and the PBS specifications.
The signaling message will be sent in the direction of the ER path The signaling message will be sent in the direction of the ER path
and the LSP is established following the normal LDP procedures. Each and the LSP is established following the normal LDP procedures. Each
LSR applies its admission control rules. If sufficient resources are LSR applies its admission control rules. If sufficient resources are
not available and the parameter values are subject to negotiation, not available and the parameter values are subject to negotiation,
then the LSR could negotiate down the PDR, the PBS, or both. then the LSR could negotiate down the PDR, the PBS, or both.
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 34 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 36 Internet Draft Constraint-Based LSP Setup using LDP July 2000
The new parameter values are echoed back in the Label Mapping The new parameter values are echoed back in the Label Mapping
Message. LSRs might need to re-adjust their resource reservations Message. LSRs might need to re-adjust their resource reservations
based on the new traffic parameter values. based on the new traffic parameter values.
B.3 Establishing CR-LSP Supporting Delay Insensitive Applications B.3 Establishing CR-LSP Supporting Delay Insensitive Applications
In this example we assume that a throughput sensitive (TS) service In this example we assume that a throughput sensitive (TS) service
is requested. For resource allocation the user assigns values for is requested. For resource allocation the user assigns values for
PDR, PBS, CDR, and CBS. The negotiation flag is set if the traffic PDR, PBS, CDR, and CBS. The negotiation flag is set if the traffic
skipping to change at line 1763 skipping to change at line 1891
high discard precedence values for all packets that exceed CDR and high discard precedence values for all packets that exceed CDR and
the CBS. The edge rules will also include dropping of packets that the CBS. The edge rules will also include dropping of packets that
conform to neither PDR nor PBS. conform to neither PDR nor PBS.
Each LSR of the LSP is expected to run its admission control rules Each LSR of the LSP is expected to run its admission control rules
and negotiate traffic parameters down if sufficient resources do not and negotiate traffic parameters down if sufficient resources do not
exist. The new parameter values are echoed back in the Label Mapping exist. The new parameter values are echoed back in the Label Mapping
Message. LSRs might need to re-adjust their resources based on the Message. LSRs might need to re-adjust their resources based on the
new traffic parameter values. new traffic parameter values.
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 35 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 37 Internet Draft Constraint-Based LSP Setup using LDP July 2000
Appendix C. LSP Modification Using CR-LDP
After a CR-LSP is set up, its bandwidth reservation may need to be
changed by the network operator, due to the new requirements for the
traffic carried on that CR-LSP. This contribution presents an
approach to modify the bandwidth and possibly other parameters of an
established CR-LSP using CR-LDP without service interruption. The
LSP modification feature can be supported by CR-LDP with a minor
extension of an _action indicator flag_. This feature has
application in dynamic network resources management where traffic of
different priorities and service classes is involved.
Conventions used in this Appendix:
L: LSP (Label Switched Path)
Lid: LSPID (LSP Identifier)
T: Traffic Parameters
R: LSR (Label Switching Router)
FTN: FEC To NHLFE
FEC: Forwarding Equivalence Class
NHLFE: Next Hop Label Forwarding Entity
TLV: Type Length Value
C.1 Introduction
Consider an LSP L1 that has been established with its set of traffic
parameters T0. A certain amount of bandwidth is reserved along the
path of L1. Consider then that some changes are required on L1. For
example, the bandwidth of L1 needs to be increased to accommodate
the increased traffic on L1. Or the SLA associated with L1 needs to
be modified because a different service class is desired. The
network operator, in these cases, would like to modify the
characteristics of L1, for example, to change its traffic parameter
set from T0 to T1, without releasing the LSP L1 to interrupt the
service. In some other cases, network operators may want to reroute
a CR-LSP to a different path for either improved performance or
better network resource utilization. In all these cases, LSP
modification is required. In section C.2 below, a method to modify
an active LSP using CR-LDP is presented. The concept of LSPID in CR-
LDP is used to achieve the LSP modification, without releasing the
LSP and interrupting the service and, without double booking the
bandwidth. Only a minimum extension on CR-LDP, an action indication
flag of _modify_ is needed in order to explicitly specify the
behavior, and allow the existing LSPID to support other networking
capabilities in the future. Section 4.5 specifies the action
indication flag of _modify_ for CR-LDP. An example is described to
demonstrate an application of the presented method in dynamically
managing network bandwidth requirements without interrupting
service.
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 36 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
C.2 Basic Procedure
LSP modification can only be allowed when the LSP is already set up
and active. That is, modification is not defined nor allowed during
the LSP establishment or label release/withdraw phases. Only
modification requested by the ingress LSR of the LSP is considered
in this draft for CR-LSP. Ingress LSR cannot modify an LSP before a
previous modification procedure is completed.
Assume that CR-LSP L1 is set up with LSPID L-id1, which is unique in
the MPLS network. The ingress LSR R1 of L1 has in its FTN (FEC To
NHLFE) table FEC1 -> Label A mapping where A is the outgoing label
for LSP L1. To modify the characteristics of L1, R1 sends a Label
Request Message. In the messages, the TLVs will have the new
requested values, and the LSPID TLV is included which indicates the
value of L-id1. The Traffic Parameters TLV, the ER-TLV, the Resource
Class (color) TLV and the Preemption TLV can have values different
from those in the original Label Request Message, which has been
used to set up L1 earlier. Thus, L1 can be changed in its bandwidth
request (traffic parameter TLV), its traffic service class (traffic
parameter TLV), the route it traverses (ER TLV) and its setup and
holding (Preemption TLV) priorities. The ingress LSR R1 now still
has the entry in FTN as FEC1 -> Label A. R1 is waiting to establish
another entry for FEC1.
When an LSR Ri along the path of L1 receives the Label Request
message, its behavior is the same as that of receiving any Label
request message. The only extension is that Ri examines the LSPID
carried in the Label Request Message, L-id1 and identifies if it
already has L-id1. If Ri does not have L-id1, Ri behaves the same as
receiving a new Label Request message. If Ri already has L-id1, Ri
takes the newly received Traffic Parameter TLV and computes the new
bandwidth required and derives the new service class. Compared with
the already reserved bandwidth for L-id1, Ri now reserves only the
difference of the bandwidth requirements. This prevents Ri from
doing bandwidth double booking. If a new service class is requested,
Ri also prepares to receive the traffic on L1 in, perhaps a
different type of queue, just the same as handling it for a Label
Request Message. Ri assigns a new label for the Label Request
Message.
When the Label Mapping message is received, two sets of labels exist
for the same LSPID. Then the ingress LSR R1 will have two outgoing
labels, A and B, associated with the same FEC, where B is the new
outgoing label received for LSP L1. The ingress LSR R1 can now
activate the new entry in FTN, FEC1 - > Label B. This means that R1
swaps traffic on L1 to the new label _B_ (_new_ path) for L1. The
packets can now be sent with the new label B, with the new set of
traffic parameters if any, on a new path, that is, if a new path is
requested in the Label Request Message for the modification. All the
other LSRs along the path will start to receive the incoming packets
with the new label. For the incoming new label, the LSR has already
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 37 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
established its mapping to the new outgoing label. Thus, the packets
will be sent out with the new outgoing label. The LSRs do not have
to implement new procedures to track the new and old
characteristics of the LSP.
The ingress LSR R1 then starts to release the original label A for
LSP L1. The Label Release Message is sent by R1 towards the down
stream LSRs. The Release message carries the LSPID of L-id1 and the
Label TLV to indicate which label is to be released. The Release
Message is propagated to the egress LSR to release the original
labels previously used for L1. Upon receiving the Label Release
Message, LSR R1 examines the LSPID, L-id1 and finds out that the L-
id1 has still another set of label (incoming/outgoing) under it.
Thus, the old label is released without releasing the resource in
use. That is, if the bandwidth has been decreased for L1, the delta
bandwidth is released. Otherwise, no bandwidth is released. This
modification procedure can not only be applied to modify the traffic
parameters and/or service class of an active LSP, but also to
reroute an existing LSP, and/or change its setup/holding priority if
desired. After the release procedure, the modification of the LSP is
completed.
The method described above follows the normal behavior of Label
Request / Mapping / Notification / Release /Withdraw procedure of a
CR-LDP operated LSR with a specific action taken on LSPID. If Label
Withdraw Message is used to withdraw a label associated with an
LSPID, the Label TLV should be included to specify which label to
withdraw. Since the LSPID can also be used for other feature
support, an action indication flag of _modify_ assigned to the LSPID
would explicitly explain the action/semantics that should be
associated with the messaging procedure. The details of this flag
are addressed in Section 4.5.
C.3 Priority Handling
When sending a Label Request Message for an active LSP L1 to request
changes, the setup priority used in the label Request Message can be
different from the one used in the previous Label Request Message,
effectively indicating the priority of this _modification_ request.
Network operators can use this feature to decide what priority is to
be assigned to a modification request, based on their
policies/algorithms and other traffic situations in the network. For
example, the priority for modification can be determined by the
priority of the customer/LSP. If a customer has exceeded the
reserved bandwidth of its VPN LSP tunnel by too much, the
modification request's priority may be given higher.
The Label Request message for the modification of an active LSP can
also be sent with a holding priority different from its previous
one. This effectively changes the holding priority of the LSP. Upon
receiving a Label Request Message that requests a new holding
priority, the LSR assigns the new holding priority to the bandwidth.
That is, the new holding priority is assigned to both the existing
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 38 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
incoming / outgoing labels and the new labels to be established for
the LSPID in question. In this way self-bumping is prevented.
C.4 Modification Failure Case Handling
A modification attempt may fail due to insufficient resource or
other situations. A Notification message is sent back to the ingress
LSR R1 to indicate the failure of Label Request Message that
intended to modify the LSP. Retry may be attempted if desired by the
network operator.
If the LSP on the original path failed when a modification attempt
is in progress, the attempt should be aborted by using the Label
Abort Request message as specified in LDP draft.
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Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 39 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-04.txt 38
 End of changes. 

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