draft-ietf-mpls-cr-ldp-02.txt   draft-ietf-mpls-cr-ldp-03.txt 
MPLS WG Bilel Jamoussi, Editor MPLS Working Group Bilel Jamoussi, Editor
Internet Draft Nortel Networks Corp. Internet Draft Nortel Networks Corp.
Expiration Date: February 2000 Expiration Date: March 2000
August 1999 September 1999
Constraint-Based LSP Setup using LDP Constraint-Based LSP Setup using LDP
draft-ietf-mpls-cr-ldp-02.txt draft-ietf-mpls-cr-ldp-03.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 44 skipping to change at line 44
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
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 (CRLSPs). support of constraint-based routed label switched paths (CR-LSPs).
Other uses exist for CRLSPs as well ([5], [6] and [7]). Other uses for CR-LSPs include MPLS-based VPNs.
This draft specifies mechanisms and TLVs for support of CRLSPs using This draft specifies mechanisms and TLVs for support of CR-LSPs
LDP. The Explicit Route object and procedures are extracted from using LDP.
[8].
Table of Contents Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 1 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 1 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Table of Contents
1. Introduction....................................................3 1. Introduction....................................................3
2. Constraint-based Routing Overview...............................3 2. Constraint-based Routing Overview...............................3
2.1 Strict and Loose Explicit Routes...............................3 2.1 Strict and Loose Explicit Routes...............................4
2.2 Traffic Characteristics........................................4 2.2 Traffic Characteristics........................................4
2.3 Pre-emption....................................................4 2.3 Pre-emption....................................................5
2.4 Route Pinning..................................................5 2.4 Route Pinning..................................................5
2.5 Resource Class.................................................5 2.5 Resource Class.................................................5
3. Solution Overview...............................................5 3. Solution Overview...............................................6
3.1 Required Messages and TLVs.....................................6 3.1 Required Messages and TLVs.....................................7
3.2 Label Request Message..........................................7 3.2 Label Request Message..........................................7
3.3 Label Mapping Message..........................................7 3.3 Label Mapping Message..........................................8
3.4 Notification Message...........................................8 3.4 Notification Message...........................................8
3.5 Release , Withdraw, and Abort Messages.........................9 3.5 Release , Withdraw, and Abort Messages.........................9
4. Protocol Specification..........................................9 4. Protocol Specification..........................................9
4.1 Explicit Route TLV (ER-TLV)....................................9 4.1 Explicit Route TLV (ER-TLV)...................................10
4.2 Explicit Route Hop TLV (ER-Hop TLV)...........................10 4.2 Explicit Route Hop TLV (ER-Hop TLV)...........................10
4.3 Traffic Parameters TLV........................................11 4.3 Traffic Parameters TLV........................................11
4.3.1 Semantics...................................................13 4.3.1 Semantics...................................................13
4.3.1.1 Frequency.................................................13 4.3.1.1 Frequency.................................................13
4.3.1.2 Peak Rate.................................................13 4.3.1.2 Peak Rate.................................................13
4.3.1.3 Committed Rate............................................13 4.3.1.3 Committed Rate............................................14
4.3.1.4 Excess Burst Size.........................................14 4.3.1.4 Excess Burst Size.........................................14
4.3.1.5 Peak Rate Token Bucket....................................14 4.3.1.5 Peak Rate Token Bucket....................................14
4.3.1.6 Committed Data Rate Token Bucket..........................14 4.3.1.6 Committed Data Rate Token Bucket..........................14
4.3.1.7 Weight....................................................15 4.3.1.7 Weight....................................................15
4.3.2 Procedures..................................................15 4.3.2 Procedures..................................................15
4.3.2.1 Label Request Message.....................................15 4.3.2.1 Label Request Message.....................................15
4.3.2.2 Label Mapping Message.....................................16 4.3.2.2 Label Mapping Message.....................................16
4.3.2.3 Notification Message......................................16 4.3.2.3 Notification Message......................................16
4.4 Preemption TLV................................................16 4.4 Preemption TLV................................................16
4.5 LSPID TLV.....................................................17 4.5 LSPID TLV.....................................................17
4.6 Resource Class (Color) TLV....................................18 4.6 Resource Class (Color) TLV....................................18
4.7 ER-Hop semantics..............................................19 4.7 ER-Hop semantics..............................................19
4.7.1. ER-Hop 1: The IPv4 prefix..................................19 4.7.1. ER-Hop 1: The IPv4 prefix..................................19
4.7.2. ER-Hop 2: The IPv6 address.................................19 4.7.2. ER-Hop 2: The IPv6 address.................................20
4.7.3. ER-Hop 3: The autonomous system number....................20 4.7.3. ER-Hop 3: The autonomous system number....................20
4.7.4. ER-Hop 4: LSPID............................................20 4.7.4. ER-Hop 4: LSPID............................................21
4.8. Processing of the Explicit Route TLV.........................22 4.8. Processing of the Explicit Route TLV.........................22
4.8.1. Selection of the next hop..................................22 4.8.1. Selection of the next hop..................................22
4.8.2. Adding ER-Hops to the explicit route TLV...................23 4.8.2. Adding ER-Hops to the explicit route TLV...................23
4.9 Route Pinning TLV.............................................23 4.9 Route Pinning TLV.............................................24
4.10 CRLSP FEC Element............................................24 4.10 CR-LSP FEC Element...........................................24
4.11 Error subcodes...............................................24 4.11 Error subcodes...............................................25
5. Security.......................................................25 5. Security.......................................................25
6. Acknowledgments................................................25 6. Acknowledgments................................................25
7. Intellectual Property Consideration............................25 7. Intellectual Property Consideration............................26
8. References.....................................................25 8. References.....................................................26
9. Author's Addresses.............................................26 9. Author's Addresses.............................................26
Appendix A: CRLSP Establishment Examples..........................29 Appendix A: CR-LSP Establishment Examples.........................29
A.1 Strict Explicit Route Example.................................29
A.2. Node Groups and Specific Nodes Example.......................30
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 2 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 2 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
A.1 Strict Explicit Route Example.................................29
A.2 Node Groups and Specific Nodes Example........................30
Appendix B. QoS Service Examples..................................33 Appendix B. QoS Service Examples..................................33
B.1 Service Examples..............................................33 B.1 Service Examples..............................................33
B.2. Establishing CR-LSP Supporting Real-Time Applications........34 B.2 Establishing CR-LSP Supporting Real-Time Applications.........34
B.3. Establishing CR-LSP Supporting Delay Insensitive Applications35 B.3 Establishing CR-LSP Supporting Delay Insensitive Applications.35
Appendix C. LSP Modification Using CR-LDP.........................36
C.1 Introduction..................................................36
C.2 Basic Procedure...............................................37
C.3 Priority Handling.............................................38
C.4 Modification Failure Case Handling............................39
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
for explicit path setup in LDP will be moved to a separate document. for explicit path setup in LDP will be moved to a separate document.
This document provides that support and it has been accepted as a This document provides that support and it has been accepted as a
working document in the Orlando meeting (December 1998). working document in the Orlando meeting (December 1998).
This specification proposes an end-to-end setup mechanism of a This specification proposes an end-to-end setup mechanism of a
constraint-based routed LSP (CRLSP) initiated by the ingress LSR. We constraint-based routed LSP (CR-LSP) initiated by the ingress LSR.
also specify mechanisms to provide means for reservation of We also specify mechanisms to provide means for reservation of
resources using LDP. resources using LDP.
This document introduce TLVs and procedures that provide support This document introduce TLVs and procedures that provide support
for: for:
- Strict and Loose Explicit Routing - Strict and Loose Explicit Routing
- Specification of Traffic Parameters - Specification of Traffic Parameters
- Route Pinning - Route Pinning
- CRLSP Pre-emption though setup/holding priorities - CR-LSP Pre-emption though setup/holding priorities
- Handling Failures - Handling Failures
- LSPID - LSPID
- Resource Class - Resource Class
Section 2 introduces the various constraints defined in this Section 2 introduces the various constraints defined in this
specification. Section 3 outlines the CR-LDP solution. Section 4 specification. Section 3 outlines the CR-LDP solution. Section 4
defines the TLVs and procedures used to setup constraint-based defines the TLVs and procedures used to setup constraint-based
routed 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 Engineering requirements defined in [4]. Explicit Routing is a
subset of the more general constraint-based routing where the subset of the more general constraint-based routing where the
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 3 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
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 2.1 Strict and Loose Explicit Routes
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 3 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Like any other LSP a CR-LSP is a path through an MPLS network. The
Like any other LSP an CRLSP 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 support the traffic sent over the LSP. The reason for setting up CR-
CRLSPs, 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.
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 CRLSP 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 CRLSP, allows the nodes, of which a subset will be traversed by the CR-LSP, allows the
system a significant amount of local flexibility in fulfilling a system a significant amount of local flexibility in fulfilling a
request for a constraint-based route. This allows the generator of request for a constraint-based route. This allows the generator of
the constraint-based route to have some degree of imperfect the constraint-based route to have some degree of imperfect
information about the details of the path. information about the details of the path.
The constraint-based route is encoded as a series of ER-Hops The constraint-based route is encoded as a series of ER-Hops
contained in a constraint-based route TLV. Each ER-Hop may identify contained in a constraint-based route TLV. Each ER-Hop may identify
a group of nodes in the constraint-based route. A constraint-based a group of nodes in the constraint-based route. A constraint-based
route is then a path including all of the identified groups of route is then a path including all of the identified groups of nodes
nodes. in the order in which they appear in the TLV.
To simplify the discussion, we call each group of nodes an abstract To simplify the discussion, we call each group of nodes an abstract
node. Thus, we can also say that a constraint-based route is a path node. Thus, we can also say that a constraint-based route is a path
including all of the abstract nodes, with the specified operations including all of the abstract nodes, with the specified operations
occurring along that path. occurring along that path.
2.2 Traffic Characteristics 2.2 Traffic Characteristics
The traffic characteristics of a path are described in the Traffic The traffic characteristics of a path are described in the Traffic
Parameters TLV in terms of a peak rate, committed rate, and service Parameters TLV in terms of a peak rate, committed rate, and service
granularity. The peak and committed rates describe the bandwidth granularity. The peak and committed rates describe the bandwidth
constraints of a path while the service granularity can be used to constraints of a path while the service granularity can be used to
specify a constraint on the delay variation that the CRLDP MPLS
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 4 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
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
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 4 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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
the new path (setup priority) to determine if the new path can pre- the new path (setup priority) to determine if the new path can pre-
empt an existing path. empt an existing path.
The setupPriority of a new CRLSP and the holdingPriority attributes The setupPriority of a new CR-LSP and the holdingPriority attributes
of the existing CRLSP are used to specify priorities. Signaling a of the existing CR-LSP are used to specify priorities. Signaling a
higher holding priority express that the path, once it has been higher holding priority express that the path, once it has been
established, should have a lower chance of being pre-empted. established, should have a lower chance of being pre-empted.
Signaling a higher setup priority expresses the expectation that, in Signaling a higher setup priority expresses the expectation that, in
the case that resource are unavailable, the path is more likely to the case that resource are unavailable, the path is more likely to
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 setupPriority of a CRLSP should not be higher (numerically less) The setupPriority of a CR-LSP should not be higher (numerically
than its holdingPriority since it might bump an LSP and be bumped by less) than its holdingPriority since it might bump an LSP and be
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
CRLSP 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 because 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 an CR-LSP is being established, it's necessary to indicate When a CR-LSP is being established, it's necessary to indicate which
which resource classes the CR-LSP can draw from. resource classes the CR-LSP can draw from.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 5 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
3. Solution Overview 3. Solution Overview
CRLSP 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.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 5 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
2. Build on already specified functionality that meets the 2. Build on already specified functionality that meets the
requirements whenever possible. Hence, this specification is requirements whenever possible. Hence, this specification is
based on [1] and the Explicit Route object and procedures based on [1].
defined in [8].
3. Keep the solution simple. 3. Keep the solution simple.
In this document, support for unidirectional point-to-point CRLSPs In this document, support for unidirectional point-to-point CR-LSPs
is specified. Support for point-to-multipoint, multipoint-to-point, is specified. Support for point-to-multipoint, multipoint-to-point,
is for further study (FFS). is for further study (FFS).
Support for constraint-based routed LSPs in this specification Support for constraint-based routed LSPs in this specification
depends on the following minimal LDP behaviors as specified in [1]: depends on the following minimal LDP behaviors as specified in [1]:
- Basic and/or Extended Discovery Mechanisms. - Use of Basic and/or Extended Discovery Mechanisms.
- Use the Label Request Message defined in [1] in downstream on - Use of the Label Request Message defined in [1] in downstream
demand label advertisement mode with ordered control. on demand label advertisement mode with ordered control.
- Use the Label Mapping Message defined in [1] in downstream on - Use of the Label Mapping Message defined in [1] in downstream
demand mode with ordered control. on demand mode with ordered control.
- Use the Notification Message defined in [1]. - Use of the Notification Message defined in [1].
- Use the Withdraw and Release Messages defined in [1]. - Use of the Withdraw and Release Messages defined in [1].
- Use the Loop Detection (in the case of loosely routed segments - Use of the Loop Detection (in the case of loosely routed
of a CRLSP) mechanisms defined in [1]. segments of a CR-LSP) mechanisms defined in [1].
In addition, the following functionality is added to what's defined In addition, the following functionality is added to what's defined
in [1]: in [1]:
- The Label Request Message used to setup a CRLSP includes one or - The Label Request Message used to setup a CR-LSP includes one
more CR-TLVs defined in Section 4. For instance, the Label or more CR-TLVs defined in Section 4. For instance, the Label
Request Message may include the ER-TLV. Request Message may include the ER-TLV.
- An LSR implicitly infers ordered control from the existence of - An LSR implicitly infers ordered control from the existence of
one or more CR-TLVs in the Label Request Message. This means 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 CRLSP. 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 CRLSP. that this is also true for the loosely routed parts of a CR-
LSP.
- New status codes are defined to handle error notification for - New status codes are defined to handle error notification for
failure of established paths specified in the CR-TLV. failure of established paths specified in the CR-TLVs.
Optional TLVs are not required in the CR-LDP messages for the Optional TLVs are not required in the CR-LDP messages for the
messages to be compliant with the protocol. Optional parameters CAN messages to be compliant with the protocol. Optional parameters MAY
be required for a particular operation to work (or work correctly), be required for a particular operation to work (or work correctly),
however. however.
Examples of CRLSP establishment are given in Appendix A to Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 6 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
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
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 6 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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 state
transitions, which relate to CR-LDP messages, can be found in [9]. transitions, which relate to CR-LDP messages, can be found in [5].
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.
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):
skipping to change at line 359 skipping to change at line 362
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| Label Request (0x0401) | Message Length | |0| Label Request (0x0401) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID | | Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC TLV | | FEC TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID TLV (mandatory) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.3 Label Mapping Message Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 7 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 7 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 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 - Only a single Label-TLV may be included in the Label Mapping
Message. 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 CRLSP 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.
2. The LSR received a mapping from its downstream next hop LSR 2. The LSR received a mapping from its downstream next hop LSR
for an CRLSP for which an upstream request is still pending. for an CR-LSP for which an upstream request is still
pending.
The encoding for the CR-LDP Label Mapping Message is as follows: The encoding for the CR-LDP Label Mapping Message is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| Label Mapping (0x0400) | Message Length | |0| Label Mapping (0x0400) | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ID | | Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at line 419 skipping to change at line 421
| Label Request Message ID TLV | | Label Request Message ID TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSPID TLV (CR-LDP, optional) | | LSPID TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic TLV (CR-LDP, optional) | | Traffic TLV (CR-LDP, optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.4 Notification Message 3.4 Notification Message
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 3.4.7 of [1]. the Status TLV encoding is as defined in Section 3.4.6 of [1].
Establishment of an Explicitly Routed LSP may fail for a variety of Establishment of an CR-LSP may fail for a variety of reasons. All
reasons. All such failures are considered advisory conditions and such failures are considered advisory conditions and they are
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 CRLSP and error notifications associated with the establishment of a CR-LSP
the processing of the CR-TLV. and the processing of the CR-TLV.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 8 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
The Notification Message must carry the LSPID TLV of the The Notification Message may carry the LSPID TLV of the
corresponding CRLSP. 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
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
skipping to change at line 461 skipping to change at line 463
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 Messages defined in [1] optionally carries one or The Label Request Message defined in [1] optionally carries one or
more of the optional Constraint-based Routing TLVs (CR-TLVs) defined more of the optional Constraint-based Routing TLVs (CR-TLVs) defined
in this section. If needed, other constraints can be supported later in this section. If needed, other constraints can be supported later
through the definition of new TLVs. In this specification, the through the definition of new TLVs. In this specification, the
following TLVs are defined: following TLVs are defined:
- Explicit Route TLV - Explicit Route TLV
- Explicit Route Hop TLV - Explicit Route Hop TLV
- Traffic Parameters TLV - Traffic Parameters TLV
- Preemption TLV - Preemption TLV
- LSPID TLV - LSPID TLV
- Route Pinning TLV - Route Pinning TLV
- Resource Class TLV - Resource Class TLV
- CRLSP 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.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 9 Internet Draft Constraint-Based LSP Setup using LDP August, 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| ER-TLV (0x0800) | Length | |0|0| ER-TLV (0x0800) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV 1 | | ER-Hop TLV 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ER-Hop TLV 2 | | ER-Hop TLV 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ............ ~ ~ ............ ~
skipping to change at line 529 skipping to change at line 531
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-Hop-Type | Length | |0|0| ER-Hop-Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Content // | |L| Content // |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
ER-Hop Type ER-Hop Type
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 10 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
A fourteen-bit field indicating the type of contents of the ER- A fourteen-bit field indicating the type of contents of the ER-
Hop. Currently defined values are: Hop. Currently defined values are:
Value Type Value Type
----- ------------------------ ----- ------------------------
0x801 IPv4 prefix 0x801 IPv4 prefix
0x802 IPv6 prefix 0x802 IPv6 prefix
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 10 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
0x803 Autonomous system number 0x803 Autonomous system number
0x804 LSPID 0x804 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 is an attribute of the ER-Hop. The L bit is set if
the ER-Hop ER-Hop represents a loose hop in the explicit route.
If the bit is not set, the ER-Hop represents a strict hop in
the explicit route.
The L bit in the ER-Hop is a one-bit attribute. If the L bit The L bit in the ER-Hop is a one-bit attribute. If the L bit
is set, then the value of the attribute is _loose._ Otherwise, is set, then the value of the attribute is _loose._ Otherwise,
the value of the attribute is _strict._ For brevity, we say the value of the attribute is _strict._ For brevity, we say
that if the value of the ER-Hop attribute is loose then it is a that if the value of the ER-Hop attribute is loose then it is a
_loose ER-Hop._ Otherwise, it's a _strict ER-Hop._ Further, _loose ER-Hop._ Otherwise, it's a _strict ER-Hop._ Further,
we say that the abstract node of a strict or loose ER-Hop is a we say that the abstract node of a strict or loose ER-Hop is a
strict or a loose node, respectively. Loose and strict nodes strict or a loose node, respectively. Loose and strict nodes
are always interpreted relative to their prior abstract nodes. are always interpreted relative to their prior abstract nodes.
The path between a strict node and its prior node MUST include The path between a strict node and its prior node MUST include
only network nodes from the strict node and its prior abstract only network nodes from the strict node and its prior abstract
node. node.
The path between a loose node and its prior node MAY include The path between a loose node and its prior node MAY include
other network nodes, which are not part of the strict node or other network nodes, which are not part of the strict node or
its prior abstract node. its prior abstract node.
Contents Contents
A variable length field containing the node or abstract node A variable length field containing a node or abstract node
that is the consecutive nodes that make up the explicit routed which is one of the consecutive nodes that make up the
LSP. explicitly routed LSP.
4.3 Traffic Parameters TLV 4.3 Traffic Parameters TLV
The following sections describe the CRLSP Traffic Parameters. The The following sections describe the CR-LSP Traffic Parameters. The
required characteristics of a CRLSP are expressed by the Traffic required characteristics of a CR-LSP are expressed by the Traffic
Parameter values. Parameter values.
A Traffic Parameters TLV, is used to signal the Traffic Parameter A Traffic Parameters TLV, is used to signal the Traffic Parameter
values. The Traffic Parameters are defined in the subsequent values. The Traffic Parameters are defined in the subsequent
sections. sections.
The Traffic Parameters TLV contains a Flags field, a Frequency, a The Traffic Parameters TLV contains a Flags field, a Frequency, a
Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS. Weight, and the five Traffic Parameters PDR, PBS, CDR, CBS, EBS.
The Traffic Parameters TLV is shown below: The Traffic Parameters TLV is shown below:
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 11 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 11 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| Traf. Param. TLV (0x0810)| Length | |0|0| Traf. Param. TLV (0x0810)| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | Frequency | Reserved | Weight | | Flags | Frequency | Reserved | Weight |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Data Rate (PDR) | | Peak Data Rate (PDR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at line 634 skipping to change at line 631
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
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
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 12 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 3-255 - Reserved
Reserved - Zero on transmission. Ignored on receipt.
2- VeryFrequest 3-255 - Reserved Reserved
Zero on transmission. Ignored on receipt.
Weight Weight
An 8 bit unsigned integer indicating the weight of the CRLSP. An 8 bit unsigned integer indicating the weight of the CR-LSP.
Valid weight values are from 1 to 255. The value 0 means that Valid weight values are from 1 to 255. The value 0 means that
weight is not applicable for the CRLSP. weight is not applicable for the CR-LSP.
Traffic Parameters Traffic Parameters
Each Traffic Parameter is encoded as a 32-bit IEEE single- Each Traffic Parameter is encoded as a 32-bit IEEE single-
precision floating-point number. A value of positive infinity precision floating-point number. A value of positive infinity
is represented as an IEEE single-precision floating-point is represented as an IEEE single-precision floating-point
number with an exponent of all ones (255) and a sign and number with an exponent of all ones (255) and a sign and
mantissa of all zeros. The values PDR and CDR are in units of mantissa of all zeros. The values PDR and CDR are in units of
bytes per second. The values PBS, CBS and EBS are in units of bytes per second. The values PBS, CBS and EBS are in units of
bytes. bytes.
The value of PDR MUST be greater than or equal to the value of The value of PDR MUST be greater than or equal to the value of
CDR in a correctly encoded Traffic Parameters TLV. CDR in a correctly encoded Traffic Parameters TLV.
4.3.1 Semantics 4.3.1 Semantics
4.3.1.1 Frequency 4.3.1.1 Frequency
The Frequency specifies at what granularity the CDR allocated to the The Frequency specifies at what granularity the CDR allocated to the
CRLSP is made available. The value VeryFrequently means that the CR-LSP is made available. The value VeryFrequent means that the
available rate should average at least the CDR when measured over available rate should average at least the CDR when measured over
any time interval equal to or longer than the shortest packet time any time interval equal to or longer than the shortest packet time
at the CDR. The value Frequently means that the available rate at the CDR. The value Frequent means that the available rate should
should average at least the CDR when measured over any time interval average at least the CDR when measured over any time interval equal
equal to or longer than a small number of shortest packet times at to or longer than a small number of shortest packet times at the
the CDR. CDR.
The value Unspecified means that the CDR MAY be provided at any The value Unspecified means that the CDR MAY be provided at any
granularity. granularity.
4.3.1.2 Peak Rate 4.3.1.2 Peak Rate
The Peak Rate defines the maximum rate at which traffic SHOULD be The Peak Rate defines the maximum rate at which traffic SHOULD be
sent to the CRLSP. 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.
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 CRLSP. be available to the CR-LSP.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 13 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
The Committed Rate is defined in terms of the two Traffic Parameters The Committed Rate is defined in terms of the two Traffic Parameters
CDR and CBS, see section 4.3.1.6 below. CDR and CBS, see section 4.3.1.6 below.
4.3.1.4 Excess Burst Size 4.3.1.4 Excess Burst Size
The Excess Burst Size may be used at the edge of an MPLS domain for The Excess Burst Size may be used at the edge of an MPLS domain for
the purpose of traffic conditioning. The EBS MAY be used to measure the purpose of traffic conditioning. The EBS MAY be used to measure
the extent by which the traffic sent on a CRLSP exceeds the the extent by which the traffic sent on a CR-LSP exceeds the
committed rate. committed rate.
The possible traffic conditioning actions, such as passing, marking The possible traffic conditioning actions, such as passing, marking
or dropping, are specific to the MPLS domain. or dropping, are specific to the MPLS domain.
The Excess Burst Size is defined together with the Committed Rate, The Excess Burst Size is defined together with the Committed Rate,
see section 4.3.1.6 below. see section 4.3.1.6 below.
4.3.1.5 Peak Rate Token Bucket 4.3.1.5 Peak Rate Token Bucket
The Peak Rate of a CRLSP is specified in terms of a token bucket P The Peak Rate of a CR-LSP is specified in terms of a token bucket P
with token rate PDR and maximum token bucket size PBS. with token rate PDR and maximum token bucket size PBS.
The token bucket P is initially (at time 0) full, i.e., the token The token bucket P is initially (at time 0) full, i.e., the token
count Tp(0) = PBS. Thereafter, the token count Tp, if less than count Tp(0) = PBS. Thereafter, the token count Tp, if less than
PBS, is incremented by one PDR times per second. When a packet of PBS, is incremented by one PDR times per second. When a packet of
size B bytes arrives at time t, the following happens: size B bytes arrives at time t, the following happens:
- If Tp(t)-B >= 0, the packet is not in excess of the peak rate - If Tp(t)-B >= 0, the packet is not in excess of the peak rate
and Tp is decremented by B down to the minimum value of 0, else and Tp is decremented by B down to the minimum value of 0, else
- the packet is in excess of the peak rate and Tp is not - the packet is in excess of the peak rate and Tp is not
decremented. decremented.
Note that according to the above definition, a positive infinite Note that according to the above definition, a positive infinite
value of either PDR or PBS implies that arriving packets are ever in value of either PDR or PBS implies that arriving packets are never
excess of the peak rate. in excess of the peak rate.
The actual implementation of a 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 CRLSP 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
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 14 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
bucket E, which also operates at rate CDR. The maximum size of the 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:
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 14 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
- If Tc is less than CBS, Tc is incremented by one, else - If Tc is less than CBS, Tc is incremented by one, else
- if Te is less then EBS, Te is incremented by one, else - if Te is less then EBS, Te is incremented by one, else
- neither Tc nor Te is incremented. - neither Tc nor Te is incremented.
When a packet of size B bytes arrives at time t, the following When a packet of size B bytes arrives at time t, the following
happens: happens:
- If Tc(t)-B >= 0, the packet is not in excess of the Committed - If Tc(t)-B >= 0, the packet is not in excess of the Committed
Rate and Tc is decremented by B down to the minimum value of 0, Rate and Tc is decremented by B down to the minimum value of 0,
else else
- if Te(t)-B >= 0, the packet is in excess of the Committed rate - if Te(t)-B >= 0, the packet is in excess of the Committed rate
but is not in excess of the EBS and Te is decremented by B down but is not in excess of the EBS and Te is decremented by B down
to the minimum value of 0, else to the minimum value of 0, else
- the packet is in excess of both the Committed Rate and the EBS - the packet is in excess of both the Committed Rate and the EBS
and neither Tc nor Tc is decremented. and neither Tc nor Te is decremented.
Note that according to the above specification, a CDR value of Note that according to the above specification, a CDR value of
positive infinity implies that arriving packets are never in excess positive infinity implies that arriving packets are never in excess
of either the Committed Rate or EBS. A positive infinite value of of either the Committed Rate or EBS. A positive infinite value of
either CBS or EBS implies that the respective limit cannot be either CBS or EBS implies that the respective limit cannot be
exceeded. exceeded.
The actual implementation of a LSR doesn't need to be modeled The actual implementation of an LSR doesn't need to be modeled
according to the above formal specification. according to the above formal specification.
4.3.1.7 Weight 4.3.1.7 Weight
The weight determines the CRLSP's relative share of the possible The weight determines the CR-LSP's relative share of the possible
excess bandwidth above its committed rate. The definition of excess bandwidth above its committed rate. The definition of
_relative share_ is MPLS domain specific. _relative share_ is MPLS domain specific.
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.
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 adjust Message by the corresponding Negotiable Flag then an LSR may replace
replace the Weight value with a lower value (down to 0). the Weight value with a lower value (down to 0).
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 15 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
If, after possible Traffic Parameter negotiation, an LSR can support If, after possible Traffic Parameter negotiation, an LSR can support
the CRLSP Traffic Parameters then the LSR MUST reserve the the CR-LSP Traffic Parameters then the LSR MUST reserve the
corresponding resources for the CRLSP. 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 CRLSP Traffic Parameters then the LSR MUST send a support the CR-LSP Traffic Parameters then the LSR MUST send a
notification message that contains the Resource Unavailable status Notification Message that contains the _Resource Unavailable_ status
code. code.
4.3.2.2 Label Mapping Message 4.3.2.2 Label Mapping Message
If an LSR receives an incorrectly encoded Traffic Parameters TLV in If an LSR receives an incorrectly encoded Traffic Parameters TLV in
which the value of PDR is less than the value of CDR then it MUST which the value of PDR is less than the value of CDR then it MUST
send a Label Release message containing the Status code Traffic send a Label Release message containing the Status code _Traffic
Parameters Unavailable to the LSR from which it received the Parameters Unavailable_ to the LSR from which it received the
erroneous message. erroneous message. In addition, the LSP should send a Notification
Message upstream with the status code _Label Request Aborted_.
If the negotiation flag was set in the label request message, the If the negotiation flag was set in the label request message, the
egress LSR MUST include the (possibly negotiated) Traffic Parameters egress LSR MUST include the (possibly negotiated) Traffic Parameters
and Weight in the Label Mapping message. and Weight in the Label Mapping message.
The Traffic Parameters and the Weight in a Label Mapping message The Traffic Parameters and the Weight in a Label Mapping message
MUST be forwarded unchanged. MUST be forwarded unchanged.
An LSR SHOULD adjust the resources that it reserved for a CRLSP when An LSR SHOULD adjust the resources that it reserved for a CR-LSP
it receives a Label Mapping Message if the Traffic Parameters differ when it receives a Label Mapping Message if the Traffic Parameters
from those in the corresponding Label Request Message. differ from those in the corresponding Label Request Message.
4.3.2.3 Notification Message 4.3.2.3 Notification Message
If an LSR receives a Notification Message for a CRLSP, it SHOULD If an LSR receives a Notification Message for a CR-LSP, it SHOULD
release any resources that it possibly had reserved for the CRLSP. 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 decerasing
the priority starting at the middle of the range. the priority starting at the middle of the range.
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 16 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| Preemption-TLV (0x0820) | Length | |0|0| Preemption-TLV (0x0820) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SetPrio | HoldPrio | Reserved | | SetPrio | HoldPrio | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 16 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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 0x810. type which is 0x820.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
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
skipping to change at line 884 skipping to change at line 883
HoldPrio HoldPrio
A HoldingPriority of value zero (0) is the priority assigned to A HoldingPriority of value zero (0) is the priority assigned to
the most important path. It is referred to as the highest the most important path. It is referred to as the highest
priority. Seven (7) is the priority for the least important priority. Seven (7) is the priority for the least important
path. The default value should be 4. path. The default value should be 4.
The higher the holding priority, the less likely it is for CR- The higher the holding priority, the less likely it is for CR-
LDP to reallocate its bandwidth to a new path. LDP to reallocate its bandwidth to a new path.
4.5 LSPID TLV 4.5 LSPID TLV
LSPID is a unique identifier of a CRLSP 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 and a Locally
unique CRLSP ID to that LSR. 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.
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. An action using an already established CR-LSP as a hop in an ER-TLV.
indicator flag_ is carried in the LSPID TLV. This _action indicator
flag_ indicates explicitly the action that should be taken if the
LSP already exists on the LSR receiving the message.
The procedure for the code point _modify_ is defined in section 2.1. An _action indicator flag_ is carried in the LSPID TLV. This _action
of [10]. The procedures for other flags are FFS. indicator flag_ indicates explicitly the action that should be taken
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
changed by the network operator, due to the new requirements for the
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
parameters of an established CR-LSP without service interruption.
This feature has application in dynamic network resources management
where traffic of different priorities and service classes is
involved.
The procedure for the code point _modify_ is defined in Appendix C.
The 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| LSPID-TLV (0x0821) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |ActFlg | Local CRLSP ID | | Reserved |ActFlg | Local CR-LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ingress LSR Router ID | | Ingress LSR Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 17 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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 type
which is 0x821. which is 0x821.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
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:
0001: modify 0000: indicates initial LSP setup
0001: indicates modify LSP
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
Local CRLSP ID Local CR-LSP ID
The Local LSP ID is an identifier of the CRLSP locally unique The Local LSP ID is an identifier of the CR-LSP locally unique
within the Ingress LSR originating the CRLDP. within the Ingress LSR originating the CR-LSP.
Ingress LSR Router ID Ingress LSR Router ID
"An LSR may use any of its own IPv4 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 CRLSP. 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| ResCls-TLV (0x0822) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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. which is 0x822.
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
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 CRLSP can _administrative groups_ or _colors_ of links the CR-LSP can
traverse. traverse.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 18 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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
skipping to change at line 993 skipping to change at line 1005
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
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| 0x802 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | PreLen | |L| Reserved | PreLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address | | IPV6 address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 19 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
| IPV6 address (continued) | | IPV6 address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
0x802 IPv6 address 0x802 IPv6 address
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
L Bit L Bit
skipping to change at line 1043 skipping to change at line 1055
Prefix Length 1-128 Prefix Length 1-128
IPv6 address IPv6 address
A 128-bit unicast host address. A 128-bit unicast host address.
4.7.3. ER-Hop 3: The autonomous system number 4.7.3. ER-Hop 3: The autonomous system number
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| 0x803 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | AS Number | |L| Reserved | AS Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
AS Number 0x803 AS Number 0x803
skipping to change at line 1069 skipping to change at line 1083
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
AS Number AS Number
Autonomous System number Autonomous System number
4.7.4. ER-Hop 4: LSPID 4.7.4. ER-Hop 4: LSPID
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 20 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
The LSPID is used to identify the tunnel ingress point as the next The LSPID is used to identify the tunnel ingress point as the next
hop in the ER. This ER-Hop allows for stacking new CR-LSPs within an hop in the ER. This ER-Hop allows for stacking new CR-LSPs within an
already established CR-LSP. It also allows for splicing the CR-LSP already established CR-LSP. It also allows for splicing the CR-LSP
being established with an existing CR-LSP. being established with an existing CR-LSP.
If an LSPID Hop is the last ER-Hop in an ER-TLV, than the LSR may If an LSPID Hop is the last ER-Hop in an ER-TLV, than the LSR may
splice the CR-LSP of the incoming Label Request to the CR-LSP that splice the CR-LSP of the incoming Label Request to the CR-LSP that
currently exists with this LSPID. This is useful, for example, at currently exists with this LSPID. This is useful, for example, at
the point at which a Label Request used for local repair arrives at the point at which a Label Request used for local repair arrives at
the next ER-Hop after the loosely specified CR-LSP segment. Use of the next ER-Hop after the loosely specified CR-LSP segment. Use of
skipping to change at line 1095 skipping to change at line 1107
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 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 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 egress. That LSR will continue processing of the CR-LSP Label
Request Message. The result is a tunneled, or stacked, CR-LSP. 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
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| 0x804 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | Local LSPID | |L| Reserved | Local LSPID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Ingress LSR Router ID | | Ingress LSR Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at line 1122 skipping to change at line 1136
Set to indicate Loose hop. Set to indicate Loose hop.
Cleared to indicate a strict hop. Cleared to indicate a strict hop.
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
Local LSPID Local LSPID
A 2 byte field indicating the LSPID which is unique with A 2 byte field indicating the LSPID which is unique with
reference to its Ingress LSR. reference to its Ingress LSR.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 21 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Ingress LSR Router ID Ingress LSR Router ID
"An LSR may use any of its own IPv4 addresses in this field" An LSR may use any of its own IPv4 addresses in this field.
4.8. Processing of the Explicit Route TLV 4.8. Processing of the Explicit Route TLV
4.8.1. Selection of the next hop 4.8.1. Selection of the next hop
A Label Request Message containing a 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.
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
error, and should return a _Bad initial ER-Hop_ error. If the
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
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. 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
the Label Request Message. This node may or may not be the the Label Request Message. This node may or may not be the
end of the LSP. Processing continues with section 4.8.2, end of the LSP. Processing continues with section 4.8.2,
where a new explicit route TLV may be added to the Label where a new explicit route TLV may be added to the Label
Request Message. Request Message.
3. If the node is also a part of the abstract node described by 3. If the node is also a part of the abstract node described by
the second ER-Hop, then the node deletes the first ER-Hop and the second ER-Hop, then the node deletes the first ER-Hop and
continues processing with step 2, above. Note that this makes continues processing with step 2, above. Note that this makes
the second ER-Hop into the first ER-Hop of the next iteration. the second ER-Hop into the first ER-Hop of the next iteration.
4. The node determines if it is topologically adjacent to the 4. The node determines if it is topologically adjacent to the
abstract node described by the second ER-Hop. If so, the node abstract node described by the second ER-Hop. If so, the node
selects a particular next hop which is a member of the selects a particular next hop which is a member of the
abstract node. The node then deletes the first ER-Hop and abstract node. The node then deletes the first ER-Hop and
continues processing with section 4.8.2. continues processing with section 4.8.2.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 22 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
5. Next, the node selects a next hop within the abstract node of 5. Next, the node selects a next hop within the abstract node of
the first ER-Hop that is along the path to the abstract node the first ER-Hop that is along the path to the abstract node
of the second ER-Hop. If no such path exists then there are of the second ER-Hop. If no such path exists then there are
two cases: two cases:
5.a If the second ER-Hop is a strict ER-Hop, then there is 5.a If the second ER-Hop is a strict ER-Hop, then there is
an 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.
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.
Alternately, if the first ER-Hop is a loose ER-Hop, an arbitrary Alternately, if the first ER-Hop is a loose ER-Hop, an arbitrary
series of ER-Hops may be inserted prior to the first ER-Hop. series of ER-Hops may be inserted prior to the first ER-Hop.
4.9 Route Pinning TLV 4.9 Route Pinning TLV
Section 2.4 describes the use of route pinning. The encoding of the
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| 0x823 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P| Reserved | |P| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
Pinning-TLV type 0x823 Pinning-TLV type 0x823
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 23 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Length Length
Specifies the length of the value field in bytes. Specifies the length of the value field in bytes.
P Bit P Bit
The P bit is set to 1 to indicate that route pinning is The P bit is set to 1 to indicate that route pinning is
requested. requested.
The P bit is set to 0 to indicate that route pinning is not The P bit is set to 0 to indicate that route pinning is not
requested requested
Reserved Reserved
Zero on transmission. Ignored on receipt. Zero on transmission. Ignored on receipt.
4.10 CRLSP 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. This new FEC element does not preclude the use of other FECs
elements (Type=0x01, 0x02, 0x03) defined in the LDP spec in CR-LDP elements (Type=0x01, 0x02, 0x03) defined in the LDP spec in CR-LDP
messages. The CRLDP FEC Element is an opaque FEC to be used only in messages. The CR-LDP FEC Element is an opaque FEC to be used 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
FEC Element Type Value FEC Element Type Value
Type name Type name
CRLSP 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| FEC(0x0100) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CR-LSP (4) | | CR-LSP (4) |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
skipping to change at line 1281 skipping to change at line 1299
CR-LSP FEC Element Type CR-LSP FEC Element Type
0x04 0x04
4.11 Error subcodes 4.11 Error subcodes
In the processing described above, certain errors need to be In the processing described above, certain errors need to be
reported as part of the Notification Message. This section defines reported as part of the Notification Message. This section defines
the status codes for the errors described in this specification. the status codes for the errors described in this specification.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 24 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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 Setup Abort (Label Request Aborted in [1]) 0x04000015
Modify request not supported 0x44000008 Modify Request Not Supported 0x44000008
5. Security 5. Security
Pre-emption has to be controlled by the MPLS domain. Pre-emption has to be controlled by the MPLS domain.
Resource reservation requires the LSRs to have an LSP admission Resource reservation requires the LSRs to have an LSP admission
control function. control function.
Traffic Engineered LSPs can bypass normal routing. Traffic Engineered LSPs can bypass normal routing.
6. Acknowledgments 6. Acknowledgments
The messages used to signal the CRLSP setup are based on the work Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 25 Internet Draft Constraint-Based LSP Setup using LDP September, 1999
done by the [1] team. The Explicit Route object and procedures used
in this specification are based on [8]. The messages used to signal the CR-LSP setup are based on the work
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, and Ankur Anand. Paul Beaubien, Matthew Yuen, Liam Casey, Ankur Anand, Adrian Farrel.
7. Intellectual Property Consideration 7. Intellectual Property Consideration
Nortel Networks may seek patent or other intellectual property The IETF has been notified of intellectual property rights claimed
protection for some or all of the technologies disclosed in this in regard to some or all of the specification contained in this
document. If any standards arising from this document are or become document. For more information consult the online list of claimed
protected by one or more patents assigned to Nortel Networks, Nortel rights.
Networks is prepared to make a license available to any qualified
applicant upon reasonable and non-discriminatory terms and
conditions. Any such licenses will be subject to negotiations
outside of the IETF.
8. References 8. 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-05), June 1999.
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-04), July 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-04), April 1999. work in progress (draft-ietf-mpls-arch-06), September 1999.
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 25 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
4 Awduche et al, "Requirements for Traffic Engineering Over 4 Awduche et al, "Requirements for Traffic Engineering Over
MPLS", work in progress (draft-ietf-mpls-traffic-eng-01), MPLS", RFC 2702, September 1999.
June 1999.
5 Heinanen et al, "MPLS Mappings of Generic VPN Mechanisms",
work in progress (draft-heinanen-generic-vpn-mpls-00),
August 1998.
6 Jamieson et al, "MPLS VPN Architecture" work in progress
(draft-jamieson-mpls-vpn-00), August 1998.
7 T. Li, "CPE based VPNs using MPLS", work in progress (draft-
li-mpls-vpn-00.txt), October 1998.
8 Guerin et al, "Setting up Reservations on Explicit Paths using
RSVP", work in progress (draft-guerin-expl-path-rsvp-01) November
1997.
9 L. Wu, et. al., "LDP State Machine" work in progress 5 L. Wu, et. al., "LDP State Machine" work in progress
(draft-ietf-mpls-ldp-state-00), Feb 1999. (draft-ietf-mpls-ldp-state-00), Feb 1999.
10 J. Ash, et. al., _LSP Modification Using CR-LDP_ work in progress
(draft-ash-crlsp-modify-00.txt), July 1999.
9. Author's Addresses 9. 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 Kungsgatan 34, PO Box 1788 P O Box 3511 Station C S:t Eriksgatan 115
Ottawa, ON K1Y 4H7 111 97 Stockholm, Sweden Ottawa, ON K1Y 4H7 PO Box 6701
Canada Phone: +46 8 441 78 34 Canada 113 85 Stockholm
Phone: +1 613 763-5827 Mobile +46 70 522 78 34 Phone: +1 613 763-5827 Tel: +46 8 508 835 00
Osama@nortelnetworks.com Loa_andersson@beynetworks.com Osama@nortelnetworks.com Fax: +46 8 508 835 01
Loa_andersson@nortelnetworks.com
Peter Ashwood-Smith Ross Callon Peter Ashwood-Smith Ross Callon
Nortel Networks IronBridge Networks Nortel Networks IronBridge Networks
P O Box 3511 Station C 55 Hayden Avenue, P O Box 3511 Station C 55 Hayden Avenue,
Ottawa, ON K1Y 4H7 Lexington, MA 02173 Ottawa, ON K1Y 4H7 Lexington, MA 02173
Canada Phone: +1-781-402-8017 Canada Phone: +1-781-402-8017
Phone: +1 613 763-4534 Rcallon@ironbridgenetworks.com Phone: +1 613 763-4534 Rcallon@ironbridgenetworks.com
Petera@nortelnetworks.com Petera@nortelnetworks.com
Ram Dantu Paul Doolan Ram Dantu Paul Doolan
Alcatel USA Inc. Ennovate Networks Alcatel USA Inc. Ennovate Networks
Jamoussi, et. al. draft-ietf-mpls-crldp-03.txt 26 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
IP Competence Center 330 Codman Hill Rd IP Competence Center 330 Codman Hill Rd
1201 E. Campbell Road.,446-315 Marlborough MA 01719 1201 E. Campbell Road.,446-315 Marlborough MA 01719
Richadson, TX USA., 75081-2206 Phone: 978-263-2002 Richadson, TX USA., 75081-2206 Phone: 978-263-2002
Phone: 972 996 2938 Pdoolan@ennovatenetworks.com Phone: 972 996 2938 Pdoolan@ennovatenetworks.com
Fax: 972 996 5902 Fax: 972 996 5902
Ram.dantu@aud.alcatel.com Ram.dantu@alcatel.com
Jamoussi, et. al. draft-ietf-mpls-crldp-02.txt 26 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Nancy Feldman Andre Fredette Nancy Feldman Andre Fredette
IBM Corp. Nortel Networks IBM Corp. Nortel Networks
17 Skyline Drive 3 Federal Street 17 Skyline Drive 600 Technology Park Drive
Hawthorne NY 10532 Billerica, MA 01821 Hawthorne NY 10532 Billerica, MA 01821
Phone: 914-784-3254 978-288-8524 Phone: 914-784-3254 978-288-8524
Nkf@us.ibm.com Fredette@baynetworks.com Nkf@us.ibm.com Fredette@nortelnetworks.com
Eric Gray Joel M. Halpern Eric Gray Joel M. Halpern
Lucent Technologies, Inc Institutional Venture Partners Lucent Technologies, Inc Institutional Venture Partners
1600 Osgood St. 650-926-5633 1600 Osgood St. 650-926-5633
North Andover, MA 01847 joel@mcquillan.com North Andover, MA 01847 Joel@mcquillan.com
Phone: 603-659-3386 Phone: 603-659-3386
Ewgray@lucent.com Ewgray@lucent.com
Juha Heinanen Fiffi Hellstrand Juha Heinanen Fiffi Hellstrand
Telia Finland, Inc. Ericsson Telecom AB Telia Finland, Inc. Ericsson Telecom AB
Myyrmaentie 2 S-126 25 STOCKHOLM Myyrmaentie 2 S-126 25 STOCKHOLM
01600 VANTAA Sweden 01600 VANTAA Sweden
Finland Tel: +46 8 719 4933 Finland Tel: +46 8 719 4933
Tel: +358 41 500 4808 etxfiff@etxb.ericsson.se Tel: +358 41 500 4808 Etxfiff@etxb.ericsson.se
Jh@telia.fi Jh@telia.fi
Bilel Jamoussi Timothy E. Kilty Bilel Jamoussi Timothy E. Kilty
Nortel Networks Corp. Northchurch Communications Nortel Networks Corp. Northchurch Communications
3 Federal Street 5 Corporate Drive, 600 Technology Park Drive 5 Corporate Drive,
Billerica, MA 01821 Andover, MA 018110 Billerica, MA 01821 Andover, MA 018110
USA phone: 978 691-4656 USA phone: 978 691-4656
Phone: +1 978 288-4506 tkilty@northc.com Phone: +1 978 288-4506 Tkilty@northc.com
Jamoussi@nortelnetworks.com Jamoussi@nortelnetworks.com
Andrew G. Malis Muckai K Girish Andrew G. Malis Muckai K Girish
Ascend Communications, Inc. SBC Technology Resources, Ascend Communications, Inc. SBC Technology Resources,
1 Robbins Road 4698 Willow Road 1 Robbins Road 4698 Willow Road
Westford, MA 01886 Pleasanton, CA 94588 Westford, MA 01886 Pleasanton, CA 94588
Phone: 978 952-7414 Phone: (925) 598-1263 Phone: 978 952-7414 Phone: (925) 598-1263
fax: 978 392-2074 Fax: (925) 598-1321 fax: 978 392-2074 Fax: (925) 598-1321
Malis@ascend.com mgirish@tri.sbc.com Malis@ascend.com Mgirish@tri.sbc.com
Kenneth Sundell Pasi Vaananen Kenneth Sundell Pasi Vaananen
Nortel Networks Nokia Telecommunications Nortel Networks Nokia Telecommunications
Architecture Lab, EMEA 3 Burlington Woods Drive, S:t Eriksgatan 115 3 Burlington Woods Drive,
Kungsgatan 34, PO Box 1788 Burlington, MA 01803 PO Box 6701 Burlington, MA 01803
111 97 Stockholm, Sweden Phone: +1-781-238-4981 113 85 Stockholm Phone: +1-781-238-4981
phone: +46 8 441-7838, Pasi.vaananen@ntc.nokia.com Tel: +46 8 508 835 00 Pasi.vaanenen@ntc.nokia.com
mobile +46 70 665-7838 Fax: +46 8 508 835 01
ksundell@nortelnetworks.com
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 27 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 27 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Tom worster Liwen Wu Ksundell@nortelnetworks.com
Tom Worster Liwen Wu
Nokia Alcatel U.S.A Nokia Alcatel U.S.A
3 Burlington Woods Dr. 44983 Knoll Square 3 Burlington Woods Dr. 44983 Knoll Square
Suite 250 Ashburn, Va. 20147 Suite 250 Ashburn, Va. 20147
Burlington MA 01803 USA Phone: (703) 724-2619 Burlington MA 01803 USA Phone: (703) 724-2619
+1 617 247 2624 FAX: (703) 724-2005 +1 617 247 2624 FAX: (703) 724-2005
tom.worster@nokia.com Liwen.wu@and.alcatel.com Tom.worster@nokia.com Liwen.wu@and.alcatel.com
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 28 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 28 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
Appendix A: CRLSP 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
CRLSP. 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 The sample network used here is a four node network with two edge
edge LSRs and two core LSRs as follows: LSRs and two core LSRs as follows:
abc abc
LSR1------LSR2------LSR3------LSR4 LSR1------LSR2------LSR3------LSR4
LSR1 generates a Label Request Message as described in Section 3.1 LSR1 generates a Label Request Message as described in Section 3.1
of this draft and sends it to LSR2. This message includes the CR- of this draft and sends it to LSR2. This message includes the CR-
TLV. TLV.
A vector of three ER-Hop TLVs <a, b, c> composes the ER-TLV. A vector of three ER-Hop TLVs <a, b, c> composes the ER-TLV.
The ER-Hop TLVs used in this example are of type 0x0801 (IPv4 The ER-Hop TLVs used in this example are of type 0x0801 (IPv4
prefix) with a prefix length of 32. Hence, each ER-Hop TLV prefix) with a prefix length of 32. Hence, each ER-Hop TLV
identifies a specific node as opposed to a group of nodes. identifies a specific node as opposed to a group of nodes.
At LSR2, the following processing of the ER-TLV per Section 4.8.1 of At LSR2, the following processing of the ER-TLV per Section 4.8.1 of
this draft takes place: this draft takes place:
1) The first hop <a> is part of the abstract node LSR2. 1) The node LSR2 is part of the abstract node described by the
Therefore, the first step passes the test. Go to step 2. first hop <a>. Therefore, the first step passes the test.
Go to step 2.
2) There is a second ER-Hop, <b>. Go to step 3. 2) There is a second ER-Hop, <b>. Go to step 3.
3) LSR2 is not part of the abstract node described by the 3) LSR2 is not part of the abstract node described by the
second ER-Hop <b>. Go to Step 4. second ER-Hop <b>. Go to Step 4.
4) LSR2 determines that it is topologically adjacent to the 4) LSR2 determines that it is topologically adjacent to the
abstract node described by the second ER-Hop <b>. LSR2 selects abstract node described by the second ER-Hop <b>. LSR2
a next hop (LSR3) which is the abstract node. LSR2 deletes the selects a next hop (LSR3) which is the abstract node. LSR2
first ER-Hop <a> from the ER-TLV which now becomes <b , c>. Go deletes the first ER-Hop <a> from the ER-TLV, which now
to Section 4.8.2. becomes <b, c>. Processing continues with Section 4.8.2.
At LSR2, the following processing of Section 4.8.2 takes place: At LSR2, the following processing of Section 4.8.2 takes place:
Executing algorithm 4.8.1 did not result in the removal of the ER- Executing algorithm 4.8.1 did not result in the removal of the ER-
TLV. TLV.
Also, LSR2 is not a member of the abstract node described by the Also, LSR2 is not a member of the abstract node described by the
first ER-Hop <b>. first ER-Hop <b>.
Finally, the first ER-Hop <b> is a strict hop. Finally, the first ER-Hop <b> is a strict hop.
Therefore, processing section 4.8.2 does not result in the insertion Therefore, processing section 4.8.2 does not result in the insertion
of new ER-Hops. The selection of the next hop has been already done of new ER-Hops. The selection of the next hop has been already done
is step 4 of Section 4.8.1 and the processing of the ER-TLV is is step 4 of Section 4.8.1 and the processing of the ER-TLV is
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 29 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 29 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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 first hop <c> is part of the abstract node LSR4. 1) The node LSR4 is part of the abstract node described by the
Therefore, the first step passes the test. Go to step 2. first hop <c>. Therefore, the first step passes the test. Go
to step 2.
2) There is no second ER-Hop, this indicates the end of the 2) There is no second ER-Hop, this indicates the end of the CR-
CRLSP. The ER-TLV is removed from the Label Request Message. LSP. The ER-TLV is removed from the Label Request Message.
Processing continues with Section 4.8.2. Processing continues with Section 4.8.2.
At LSR4, the following processing of Section 4.8.2 takes place: At LSR4, the following processing of Section 4.8.2 takes place:
Executing algorithm 4.8.1 resulted in the removal of the ER-TLV. Executing algorithm 4.8.1 resulted in the removal of the ER-TLV.
LSR4 does not add a new ER-TLV. LSR4 does not add a new ER-TLV.
Therefore, processing section 4.8.2 does not result in the insertion Therefore, processing section 4.8.2 does not result in the insertion
of new ER-Hops. This indicates the end of the CRLSP and the of new ER-Hops. This indicates the end of the CR-LSP and the
processing of the ER-TLV is completed at LSR4. processing of the ER-TLV is completed at LSR4.
At LSR4, processing of Section 3.2 is invoked. The first condition At LSR4, processing of Section 3.2 is invoked. The first condition
is satisfied (LSR4 is the egress end of the CRLSP and upstream is satisfied (LSR4 is the egress end of the CR-LSP and upstream
mapping has been requested). Therefore, a Label Mapping Message is mapping has been requested). Therefore, a Label Mapping Message is
generated by LSR4 and sent to LSR3. generated by LSR4 and sent to LSR3.
At LSR3, the processing of Section 3.2 is invoked. The second At LSR3, the processing of Section 3.2 is invoked. The second
condition is satisfied (LSR3 received a mapping from its downstream condition is satisfied (LSR3 received a mapping from its downstream
next hop LSR4 for a CRLSP for which an upstream request is still next hop LSR4 for a CR-LSP for which an upstream request is still
pending). Therefore, a Label Mapping Message is generated by LSR3 pending). Therefore, a Label Mapping Message is generated by LSR3
and sent to LSR2. and sent to LSR2.
At LSR2, a similar processing to LSR 3 takes place and a Label At LSR2, a similar processing to LSR 3 takes place and a Label
Mapping Message is sent back to LSR1 which completes the end-to-end Mapping Message is sent back to LSR1, which completes the end-to-end
CRLSP setup. CR-LSP setup.
A.2. Node Groups and Specific Nodes Example A.2 Node Groups and Specific Nodes Example
A request at ingress LSR to setup a CRLSP might originate from a A request at ingress LSR to setup a CR-LSP might originate from a
management system or an application, the details are implementation management system or an application, the details are implementation
specific. specific.
The ingress LSR uses information provided by the management system The ingress LSR uses information provided by the management system
or 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 a 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-02.txt 30 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 30 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
abstract node representing a group of nodes, an abstract node abstract node representing a group of nodes, an abstract node
representing a specific node, another abstract node representing a representing a specific node, another abstract node representing a
group of nodes, and an abstract node representing a specific egress group of nodes, and an abstract node representing a specific egress
point. point.
In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B} In--{Group 1}--{Specific A}--{Group 2}--{Specific Out: B}
The ER-TLV contains four ER-Hop TLVs: The ER-TLV contains four ER-Hop TLVs:
1. An ER-Hop TLV that specifies a group of LSR valid for the 1. An ER-Hop TLV that specifies a group of LSR valid for the
first abstract node representing a group of nodes (Group 1). first abstract node representing a group of nodes (Group 1).
2. An ER-Hop TLV that indicates the specific node (Node A). 2. An ER-Hop TLV that indicates the specific node (Node A).
3. An ER-Hop TLV that specifies a group of LSRs valid for the 3. An ER-Hop TLV that specifies a group of LSRs valid for the
second abstract node representing a group of nodes (Group second abstract node representing a group of nodes (Group
2). 2).
4. An ER-Hop TLV that indicates the specific egress point for 4. An ER-Hop TLV that indicates the specific egress point for
the CRLSP (Node B). the CR-LSP (Node B).
All the ER-Hop TLVs are strictly routed nodes. All the ER-Hop TLVs are strictly routed nodes.
The setup procedure for this CRLSP works as follows: The setup procedure for this CR-LSP works as follows:
1. The ingress node sends the Label Request Message to a node 1. The ingress node sends the Label Request Message to a node
that is a member the group of nodes indicated in the first that is a member the group of nodes indicated in the first
ER-Hop TLV, following normal routing for the specific node ER-Hop TLV, following normal routing for the specific node
(A). (A).
2. The node that receives the message identifies itself as part 2. The node that receives the message identifies itself as part
of the group indicated in the first ER-Hop TLV, and that it of the group indicated in the first ER-Hop TLV, and that it
is not the specific node (A) in the second. Further it is not the specific node (A) in the second. Further it
realizes that the specific node (A) is not one of its next realizes that the specific node (A) is not one of its next
hops. hops.
3. It keeps the ER-Hop TLVs intact and sends a Label Request 3. It keeps the ER-Hop TLVs intact and sends a Label Request
Message to a node that is part of the group indicated in the Message to another node that is part of the group indicated
first ER-Hop TLV (Group 1), following normal routing for the in the first ER-Hop TLV (Group 1), following normal routing
specific node (A). for the specific node (A).
4. The node that receives the message identifies itself as part 4. The node that receives the message identifies itself as part
of the group indicated in the first ER-Hop TLV, and that it of the group indicated in the first ER-Hop TLV, and that it
is not the specific node (A) in the second ER-Hop TLV. 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-02.txt 31 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 31 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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
(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 CRLSP, it returns a Label Mapping Message, that will for the CR-LSP, it returns a Label Mapping Message, that
traverse the same path as the Label Request Message in the will traverse the same path as the Label Request Message in
opposite direction. the opposite direction.
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 32 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 32 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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 to pass, mark, and drop capabilities. The edge rules are expected tobe
be defined by the mutual agreements between the service providers defined by the mutual agreements between the service providers and
and their customers and they will constitute an essential part of their customers and they will constitute an essential part of the
the SLA. Therefore edge rules are not included in the signaling SLA. Therefore edge rules are not included in the signaling
protocol. protocol.
Packet treatment at a network node is usually referred to as the Packet treatment at a network node is usually referred to as the
local behavior. Local behavior could be specified in many ways. One local behavior. Local behavior could be specified in many ways. One
example for local behavior specification is the service frequency example for local behavior specification is the service frequency
introduced in section 4.3.2.1, together with the resource introduced in section 4.3.2.1, together with the resource
reservation rules implemented at the nodes. reservation rules implemented at the nodes.
Edge rules and local behaviors can be viewed as the main building Edge rules and local behaviors can be viewed as the main building
blocks for the end-to-end service construction. The following table blocks for the end-to-end service construction. The following table
skipping to change at line 1683 skipping to change at line 1680
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-02.txt 33 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 33 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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.
The TS refers to a generic throughput sensitive service where the The TS refers to a generic throughput sensitive service where the
network commits to deliver with high probability user datagrams at a network commits to deliver with high probability user datagrams at a
rate of at least CDR. The user may transmit at a rate higher than rate of at least CDR. The user may transmit at a rate higher than
CDR but datagrams in excess of CDR would have a lower probability of CDR but datagrams in excess of CDR would have a lower probability of
being delivered. being delivered.
The BE is the best effort service and it implies that there are no The BE is the best effort service and it implies that there are no
expected service guarantees from the network. expected service guarantees from the network.
B.2. Establishing CR-LSP Supporting Real-Time Applications B.2 Establishing CR-LSP Supporting Real-Time Applications
In this scenario the customer needs to establish an LSP for In this scenario the customer needs to establish an LSP for
supporting real-time applications such voice and video. The Delay- supporting real-time applications such as voice and video. The
sensitive (DS) service is requested in this case. Delay-sensitive (DS) service is requested in this case.
The first step is the specification of the traffic parameters in the The first step is the specification of the traffic parameters in the
signaling message. The two parameters of interest to the DS service signaling message. The two parameters of interest to the DS service
are the PDR and the PBS and the user based on his requirements are the PDR and the PBS and the user based on his requirements
specifies their values. Since all the traffic parameters are specifies their values. Since all the traffic parameters are
included in the signaling message, appropriate values must be included in the signaling message, appropriate values must be
assigned to all of them. For DS service, the CDR and the CBS values assigned to all of them. For DS service, the CDR and the CBS values
are set equal to the PDR and the PBS respectively. An indication of are set equal to the PDR and the PBS respectively. An indication of
whether the parameter values are subject to negotiation is flagged. whether the parameter values are subject to negotiation is flagged.
The transport characteristics of the DS service require that The transport characteristics of the DS service require Frequent
Frequent frequency to be requested to reflect the real-time delay frequency to be requested to reflect the real-time delay
requirements of the service. requirements of the service.
In addition to the transport characteristics, both the network In addition to the transport characteristics, both the network
provider and the customer need to agree on the actions enforced at provider and the customer need to agree on the actions enforced at
the edge. The specification of those actions is expected to be a the edge. The specification of those actions is expected to be a
part of the service level agreement (SLA) negotiation and is not part of the service level agreement (SLA) negotiation and is not
included in the signaling protocol. For DS service, the edge action included in the signaling protocol. For DS service, the edge action
is to drop packets that exceed the PDR and the PBS specifications. is to drop packets that exceed the PDR and the PBS specifications.
The signaling message will be sent in the direction of the ER path The signaling message will be sent in the direction of the ER path
and the LSP is established following the normal LDP procedures. Each and the LSP is established following the normal LDP procedures. Each
LSR applies its admission control rules. If sufficient resources are LSR applies its admission control rules. If sufficient resources are
not available and the parameter values are subject to negotiation, not available and the parameter values are subject to negotiation,
then the LSR could negotiate down the PDR, the PBS, or both. then the LSR could negotiate down the PDR, the PBS, or both.
Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 34 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 34 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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
parameters are subject to negotiation. parameters are subject to negotiation.
Since the service is delay insensitive by definition, the Since the service is delay insensitive by definition, the
Unspecified frequency is signaled to indicate that the service Unspecified frequency is signaled to indicate that the service
frequency is not an issue. frequency is not an issue.
Similar to the previous example, the edge actions are not subject Similar to the previous example, the edge actions are not subject
for signaling and are specified in the service level agreement for signaling and are specified in the service level agreement
between the user and the network provider. between the user and the network provider.
For TS service, the edge rules might include marking to indicate For TS service, the edge rules might include marking to indicate
high 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
are do not 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-02.txt 35 Internet Draft Constraint-Based LSP Setup using LDP August, 1999 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 35 Internet Draft Constraint-Based LSP Setup using LDP August, 1999
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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and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
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document itself may not be modified in any way, such as by removing document itself may not be modified in any way, such as by removing
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Jamoussi, et. al. draft-ietf-mpls-cr-ldp-02.txt 36 Jamoussi, et. al. draft-ietf-mpls-cr-ldp-03.txt 39
 End of changes. 

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