draft-ietf-mpls-p2mp-requirement-02.txt   draft-ietf-mpls-p2mp-requirement-03.txt 
Network Working Group Seisho Yasukawa (NTT) Network Working Group Seisho Yasukawa (NTT)
Internet Draft Editor Internet Draft Editor
Category: Standards Track Category: Informational
Expiration Date: August 2004 March 2004
Requirements for Point to Multipoint extension to RSVP-TE Expiration Date: December 2004 July 2004
<draft-ietf-mpls-p2mp-requirement-02.txt>
Requirements for Point to Multipoint Traffic Engineered MPLS LSPs
<draft-ietf-mpls-p2mp-requirement-03.txt>
Status of this Memo Status of this Memo
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Abstract Abstract
This document presents a basic set of requirements for Point-to- This document presents a set of requirements for
Multipoint(P2MP) Traffic Engineering (TE) extensions to Multiprotocol Point-to-Multipoint(P2MP) Traffic Engineered (TE) Multiprotocol
Label Switching (MPLS). It specifies functional requirements for Label Switching (MPLS) Label Switched Paths (LSPs). It specifies
RSVP-TE in order to deliver P2MP applications over a MPLS TE functional requirements for solutions in order to deliver P2MP
infrastructure. It is intended that solutions that specify RSVP-TE applications over a MPLS TE infrastructure. It is intended that
procedures for P2MP TE LSP setup satisfy these requirements. There is solutions that specify procedures for P2MP TE LSP setup satisfy
no intent to specify solution specific details in this document. these requirements.
There is no intent to either specify solution specific details in
this document or application specific requirements.
It is intended that the requirements presented in this document are It is intended that the requirements presented in this document are
not limited to the requirements of packet switched networks, but also not limited to the requirements of packet switched networks, but
encompass the requirements of L2SC, TDM, lambda and port switching also encompass the requirements of L2SC, TDM, lambda and port
networks managed by Generalized MPLS (GMPLS) protocols. Protocol switching networks managed by Generalized MPLS (GMPLS) protocols.
solutions developed to meet the requirements set out in this document Protocol solutions developed to meet the requirements set out in
must be equally applicable to MPLS and GMPLS. this document must attempt to be equally applicable to MPLS and
GMPLS.
Table of Contents Table of Contents
1. Introduction ................................................. 04
1. Introduction .................................................. 4 2. Definitions .................................................. 05
2. Definitions ................................................... 5 2.1 Acronyms ................................................. 05
2.1 Acronyms .................................................. 5 2.2 Terminology .............................................. 06
2.2 Terminology ............................................... 5 2.3 Conventions .............................................. 07
2.3 Conventions ............................................... 7 3. Problem Statement ............................................ 07
3. Problem statements ............................................ 7 3.1 Motivation ............................................... 07
3.1 Motivation ................................................ 7 3.2 Requirements Overview .................................... 08
3.2 Requirements overview ..................................... 8 4. Examples of candidate applications that may require
4. Application Specific Requirements .............................10 P2MP TE LSP ...................................................10
4.1 P2MP tunnel for IP multicast data .........................10 4.1 P2MP TE LSP for IP multicast data ....................... 10
4.2 P2MP TE backbone network for IP multicast network .........11 4.2 P2MP TE backbone network for IP multicast network ....... 11
4.3 Layer 2 Multicast Over MPLS ...............................12 4.3 Layer 2 Multicast Over MPLS ............................. 13
4.4 VPN multicast network .....................................13 4.4 VPN multicast network ................................... 13
4.5 GMPLS network .............................................14 4.5 GMPLS Networks .......................................... 14
5. Detailed requirements for P2MP TE extensions ..................14 5. Detailed requirements for P2MP TE extensions ................. 15
5.1 P2MP LSP tunnels ..........................................14 5.1 P2MP LSP tunnels ........................................ 15
5.2 P2MP explicit routing .....................................15 5.2 P2MP explicit routing ................................... 15
5.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes .16 5.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes.17
5.4 P2MP TE LSP establishment, teardown, and modification 5.4 P2MP TE LSP establishment, teardown, and modification
mechanisms ................................................17 mechanisms .............................................. 17
5.5 Failure Reporting and Error Recovery ......................17 5.5 Fragmentation ........................................... 18
5.6 Record route of P2MP TE LSP tunnels .......................18 5.6 Failure Reporting and Error Recovery .................... 18
5.7 Call Admission Control (CAC) and QoS control mechanism 5.7 Record route of P2MP TE LSP tunnels ..................... 19
of P2MP TE LSP tunnels ....................................18 5.8 Call Admission Control (CAC) and QoS Control mechanism .. 19
5.8 Reoptimization of P2MP TE LSP .............................19 5.9 Reoptimization of P2MP TE LSP ........................... 20
5.9 IPv4/IPv6 support .........................................19 5.10 IPv4/IPv6 support ....................................... 20
5.10 P2MP MPLS Label ..........................................20 5.11 P2MP MPLS Label ......................................... 21
5.11 Routing advertisement of P2MP capability .................20 5.12 Routing advertisement of P2MP capability ................ 21
5.12 Multi-Area/AS LSP ........................................20 5.13 Multi-Area/AS LSP ....................................... 21
5.13 P2MP MPLS OAM ............................................20 5.14 P2MP MPLS OAM ........................................... 21
5.14 Scalability ..............................................21 5.15 Scalability ............................................. 22
5.15 Backwards Compatibility ..................................21 5.16 Backwards Compatibility ................................. 22
5.16 GMPLS ....................................................22 5.17 GMPLS ................................................... 23
5.17 Requirements for Hierarchical P2MP TE LSPs ...............22 5.18 Requirements for Hierarchical P2MP TE LSPs .............. 24
5.18 P2MP Crankback routing ...................................23 5.19 P2MP Crankback routing .................................. 24
6. Security Considerations........................................23 6. Security Considerations ...................................... 24
7. Acknowledgements ..............................................23 7. Acknowledgements ............................................. 25
8. References ....................................................23 8. References ................................................... 25
8.1 Normative References ......................................23 8.1 Normative References ..................................... 25
8.2 Informational References ..................................24 8.2 Informational References ................................. 26
9. Editor's Address ..............................................26 9. Editor's Address ............................................. 27
10. Authors' Addresses ............................................26 10. Authors' Addresses .......................................... 27
11. Intellectual Property Consideration ...........................27 11. Intellectual Property Consideration ......................... 29
11.1 IPR Disclosure Acknowledgement ...........................28 11.1 IPR Disclosure Acknowledgement .......................... 29
12. Full Copyright Statement ......................................28 12. Full Copyright Statement .................................... 29
1. Introduction 1. Introduction
Existing MPLS Traffic Engineering (MPLS-TE) allows for strict QoS Existing MPLS Traffic Engineering (MPLS-TE) allows for strict QoS
guarantees, resources optimization, and fast failure recovery, but is guarantees, resources optimization, and fast failure recovery, but
limited to P2P applications. There are P2MP applications like Content is limited to P2P applications. There are P2MP applications like
Distribution, Interactive Multimedia and VPN multicast that would Content Distribution, Interactive Multimedia and VPN multicast that
also benefit from these TE capabilities. This clearly motivates would also benefit from these TE capabilities. This clearly
enhancements of the base MPLS-TE tool box in order to support P2MP motivates enhancements of the base MPLS-TE tool box in order to
applications. support P2MP applications.
This document presents a set of requirements for Point-to-Multipoint This document presents a set of requirements for
(P2MP) Traffic Engineering (TE) extensions to Multiprotocol Label Point-to-Multipoint(P2MP) Traffic Engineering (TE) extensions to
Switching (MPLS). It specifies functional requirements for RSVP-TE Multiprotocol Label Switching (MPLS). It specifies functional
[RFC3209] in order to deliver P2MP applications over a MPLS TE. requirements for solutions to deliver P2MP TE LSPs. For the sake of
illustration, RSVP-TE [RFC3209] is one possible candidate to provide
such a solution so as to deliver P2MP TE LSPs.
It is intended that solutions, that specify RSVP-TE It is intended that solutions that specify procedures for
procedures and extensions for P2MP TE LSP setup, satisfy these P2MP TE LSP setup satisfy these requirements. There is no intent to
requirements. It is not intended to specify solution specific details either specify solution specific details in this document or
in this document. application specific requirements.
It is intended that the requirements presented in this document are It is intended that the requirements presented in this document are
not limited to the requirements of packet switched networks, but also not limited to the requirements of packet switched networks, but
encompass the requirements of TDM, lambda and port switching networks also encompass the requirements of TDM, lambda and port switching
managed by Generalized MPLS (GMPLS) protocols. Protocol solutions networks managed by Generalized MPLS (GMPLS) protocols. Protocol
developed to meet the requirements set out in this document must be solutions developed to meet the requirements set out in this
equally applicable to MPLS and GMPLS. document must attempt to be equally applicable to MPLS and GMPLS.
Content Distribution (CD), Interactive multi-media (IMM), and VPN Content Distribution (CD), Interactive multi-media (IMM), and VPN
multicast are applications that are best supported with multicast multicast are applications that are best supported with multicast
capabilities. One possible way to map P2MP flows onto LSPs in a MPLS capabilities. For some of them , there is a requirement to use P2MP
network is to setup multiple P2P TE LSPs, one to each of the required TE LSPs. One possible way to map P2MP flows onto LSPs in a MPLS
egress LSRs. This requires replicating incoming packets to all the network is to setup multiple P2P TE LSPs, one to each of the
P2P LSPs at the ingress LSR to accommodate multipoint communication. required egress LSRs. This requires replicating incoming packets to
This is sub-optimal. It places the replication burden on the ingress all the P2P LSPs at the ingress LSR to accommodate multipoint
LSR and hence has very poor scaling characteristics. It also wastes communication. This is sub-optimal as it places the replication
bandwidth resources, memory and MPLS (e.g. label) resources in the burden on the ingress LSR and hence has very poor scaling
network. characteristics. It also wastes bandwidth resources, memory and
MPLS (e.g. label) resources in the network.
Hence, to provide TE for a P2MP application in an efficient manner Hence, to provide TE for a P2MP application in an efficient manner
in a large-scale environment, P2MP TE mechanisms are required (that is, with scalable impact on signaling and protocol state) in
specifically to support P2MP TE LSPs. Existing MPLS TE mechanisms a large-scale environment, P2MP TE mechanisms are required
[RFC3209] do not support P2MP TE LSPs so new mechanisms must be specifically to support P2MP TE LSPs. As of now, existing MPLS TE
developed. mechanisms such as [RFC3209] do not support P2MP TE LSPs so new
mechanisms must be developed.
This should be achieved without running a multicast routing protocol This should be achieved without requiring the use of a multicast
in the network core, and with maximum re-use of the existing MPLS routing protocol in the network core, and with maximum re-use of the
protocols: in particular, MPLS Traffic Engineering. existing MPLS protocols: in particular, MPLS Traffic
Engineering. That is, the separation between routing and signaling
that exists in the P2P TE network should be maintained within the
P2MP TE network, and the construction of the TEDB from which P2MP TE
LSP paths are computed should not be constrained to use a multicast
protocol.
A P2MP TE LSP will be set up with TE constraints and will allow A P2MP TE LSP will be set up with TE constraints and will allow
efficient packet or data replication at various branching points in efficient packet or data replication at various branching points in
the network. RSVP-TE will be used for setting up a P2MP TE LSP with the network. Note that the notion of "efficient" packet replication
enhancements to existing P2P TE LSP procedures. The P2MP TE LSP setup is relative and may have different meanings depending on the
mechanism will include the ability to add/remove receivers to/from an objectives (see section 5.2).
existing P2MP TE LSP.
Moreover, multicast traffic cannot currently benefit from P2P TE For instance, RSVP-TE could be used for setting up a P2MP TE LSP
LSPs. Hence, CAC for P2P TE LSP cannot take into account the with enhancements to existing P2P TE LSP procedures.
P2MP TE LSP setup mechanisms MUST include the ability to add/remove
receivers to/from an existing P2MP TE LSP.
Note that with existing multicast routing mechanisms, multicast
traffic cannot currently benefit from P2P TE LSPs. Hence, Call
Admission Control for P2P TE LSP cannot take into account the
bandwidth used for multicast traffic. P2MP TE will allow the bandwidth used for multicast traffic. P2MP TE will allow the
bandwidth used by unicast and multicast traffic to be counted by bandwidth used by both the unicast and multicast traffics to be
means of CAC. counted by means of CAC.
The problem statement is discussed in Section 3. This This document is organized as follows: Section 2 provides a set of
document discusses various applications that can use P2MP TE LSP. definitions used throughout the document. The problem statement is
then discussed in Section 3. for the sake of illustration, this
document lists various applications that could make use P2MP TE
LSP. Detailed application-specific requirements as far as
P2MP TE LSP is concerned are out of the scope of this document.
Detailed requirements for the support of applications that require
P2MP MPLS TE LSPs are described in section 4.
Detailed requirements for the setup of a P2MP MPLS TE LSP using The requirement for Multipoint-to-Point and Multipoint-to-Multipoint
RSVP-TE are described. Application specific requirements are also TE LSPs are outside of the scope of this document.
described.
2. Definitions 2. Definitions
2.1 Acronyms 2.1 Acronyms
P2P: P2P:
Point-to-point Point-to-point
P2MP: P2MP:
skipping to change at page 5, line 45 skipping to change at page 6, line 13
Point-to-multipoint Point-to-multipoint
2.2 Terminology 2.2 Terminology
The reader is assumed to be familiar with the terminology in The reader is assumed to be familiar with the terminology in
[RFC3031] and [RFC3209]. [RFC3031] and [RFC3209].
P2MP TE LSP: P2MP TE LSP:
A traffic engineered label switched path that has one unique A traffic engineered label switched path that has one unique
ingress LSR (also referred to as the root) and more than one ingress LSR (also referred to as the root) and one or more
egress LSR (also referred to as the leaf). egress LSRs (also referred to as the leaf).
P2MP tree: P2MP tree:
The ordered set of LSRs and links that comprise the path of The ordered set of LSRs and links that comprise the path of a
a P2MP TE LSP from its ingress LSR to all of its egress LSRs. P2MP TE LSP from its ingress LSR to all of its egress LSRs.
sub-P2MP tree: sub-P2MP tree:
A sub-P2MP tree is a portion of a P2MP tree starting at A sub-P2MP tree is a portion of a P2MP tree starting at
a particular LSR that is a member of the P2MP tree and includes a particular LSR that is a member of the P2MP tree and includes
ALL downstream LSRs that are also members of the P2MP tree. ALL downstream LSRs that are also members of the P2MP tree.
P2P sub-LSP: P2P sub-LSP:
The path from the ingress LSR to a particular egress LSR. The path from the ingress LSR to a particular egress LSR.
ingress LSR: ingress LSR:
The LSR that is responsible for initiating the signaling messages The LSR that is responsible for initiating the signaling
that set up the P2MP TE LSP. messages that set up the P2MP TE LSP.
egress LSR: egress LSR:
One of potentially many destinations of the P2MP TE LSP. Egress One of potentially many destinations of the P2MP TE LSP.
LSRs may also be referred to as leaf nodes or leaves. Egress LSRs may also be referred to as leaf nodes or leaves.
bud LSR: bud LSR:
An LSR that is an egress, but also has one or more directly An LSR that is an egress, but also has one or more directly
connected downstream LSRs. connected downstream LSRs.
branch LSR: branch LSR:
An LSR that has more than one directly connected downstream LSR. An LSR that has more than one directly connected downstream LSR.
graft LSR: graft LSR:
An LSR that is already a member of the P2MP tree and is in An LSR that is already a member of the P2MP tree and is in
process of signaling a new sub-P2MP tree. process of signaling a new sub-P2MP tree.
prune LSR: prune LSR:
An LSR that is already a member of the P2MP tree and is in An LSR that is a member of the P2MP tree and is in
process of tearing down an existing sub-P2MP tree. process of tearing down an existing sub-P2MP tree.
P2MP-ID (Pid): P2MP-ID (Pid):
The ID that can be used to map a set of P2P sub- LSPs to a The ID that can be used to map a set of P2P sub- LSPs to a
particular P2MP LSP. particular P2MP LSP.
2.3 Conventions 2.3 Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
document are to be interpreted as described in [RFC2119]. this document are to be interpreted as described in [RFC2119].
3. Problem Statement 3. Problem Statement
3.1 Motivation 3.1 Motivation
Content Distribution (CD), Interactive multi-media (IMM), and VPN Content Distribution (CD), Interactive multi-media (IMM), and VPN
multicast are applications that are best supported with multicast multicast are applications that are best supported with multicast
capabilities. capabilities.
IP Multicast provides P2MP communication. However, there are no IP Multicast provides P2MP communication. However, there are no
Traffic Engineering (TE) capabilities or QoS guarantees with existing Traffic Engineering (TE) capabilities or QoS guarantees with
IP multicast protocols. Note that Diff-serv (see [RFC2475],[RFC2597] existing IP multicast protocols. Note that Diff-serv
and [RFC3246]) combined with IP multicast routing may not be (see [RFC2475],[RFC2597] and [RFC3246]) combined with IP multicast
sufficient for P2MP applications for many of the same reasons that routing may not be sufficient for P2MP applications for many of the
it is not sufficient for unicast applications. Note also that same reasons that it is not sufficient for unicast applications.
multicast tree provided by existing IP multicast routing protocols Note also that multicast trees provided by existing IP multicast
are not optimal, which may lead to significant bandwidth wasting. routing protocols are not optimal from a bandwidth usage
TE and Constraint Based Routing, including Call Admission Control perspective, which may lead to significant bandwidth wasting.
(CAC), explicit source routing and bandwidth reservation, is required
to enable efficient resource optimization, strict QoS guarantees, and
fast recovery around network failures.
Furthermore there are no existing P2MP mechanisms for carrying TE and Constraint Based Routing, including Call Admission
layer 2 or SONET/SDH multicast traffic over MPLS. TE capabilities are Control(CAC), explicit source routing and bandwidth reservation, is
desirable for both these applications. required to enable efficient resource usage and strict QoS
guarantees.
Furthermore there are no existing P2MP mechanisms for carrying layer
2 or SONET/SDH multicast traffic over MPLS. TE capabilities are
desirable for both these applications; the related set of application
requirements are outside of the scope of this document and might
require special pseudowire encapsulation.
One possible solution would be to setup multiple P2P TE LSPs, one to One possible solution would be to setup multiple P2P TE LSPs, one to
each of the required egress LSRs. This requires replicating incoming each of the required egress LSRs. This requires replicating incoming
traffic to all the P2P LSPs at the ingress LSR to accommodate traffic to all the P2P LSPs at the ingress LSR to accommodate
multipoint communication. This is clearly sub-optimal. It places the multipoint communication. This is clearly sub-optimal as it places
replication burden on the ingress LSR and hence has very poor scaling the replication burden on the ingress LSR and hence has very poor
characteristics. It also wastes bandwidth resources, memory and MPLS scaling characteristics. It also wastes bandwidth resources, memory
(e.g. label) resources in the network. and MPLS(e.g. label) resources in the network.
Hence, to provide MPLS TE [RFC2702] for a P2MP application in an Hence, to provide MPLS TE [RFC2702] for a P2MP application in an
efficient manner in a large scale environment, P2MP TE mechanisms are efficient manner (that is, with scalable impact on signaling and
required. Existing MPLS P2P TE mechanisms have to be enhanced to protocol state) in a large scale environment, P2MP TE mechanisms
support P2MP TE LSP. are required. Existing MPLS P2P TE mechanisms have to be enhanced
to support P2MP TE LSP.
3.2. Requirements Overview 3.2. Requirements Overview
This document states basic requirements for the setup of P2MP TE This document states basic requirements for the setup of P2MP TE
LSPs. This should be achieved without running a multicast routing LSPs and a solution SHOULD satisfy them without requiring that a
protocol in the network core and with maximum re-use of the existing multicast routing protocol is used, although such a protocol
MPLS protocols. Note that the use of MPLS forwarding to carry the MUST NOT be prohibited. It is desirable to maximize the re-use of
multicast traffic may also be useful in the context of some network existing MPLS TE techniques and protocols. Note that the use of
design where it is being desired to avoid running some multicast MPLS forwarding to carry the multicast traffic may also be useful
routing protocol like PIM [PIM-SM] or BGP (which might be required in the context of some network designs where it might be desired to
for the use of PIM). avoid running some multicast routing protocol like PIM [PIM-SM] or
BGP (which might be required for the use of PIM).
A P2MP LSP will be set up with TE constraints and will allow A P2MP TE LSP path will be computed taking into account various
efficient MPLS packet replication at various branching points in the constraints such as bandwidth, affinities, required level of
network. RSVP-TE will be used for setting up a P2MP TE LSP with protection and so on. The solution MUST allow for the computation
enhancements to existing P2P TE LSP procedures. of P2MP TE LSP paths satisfying constraints with the objective of
supporting various optimization criteria such as delays, bandwidth
consumption in the network, or any other combinations.
The P2MP TE LSP setup mechanism will include the ability to This document does not restrict the choice of signaling protocol
add/remove egress LSRs to/from an existing P2MP TE LSP and should used to set up a P2MP TE LSP, but it should be noted that [RFC3468]
support all the TE LSP management procedures defined for P2P TE LSP states
(like the non disruptive rerouting - the so called "Make before ... the consensus reached by the Multiprotocol Label Switching
break" procedure). (MPLS) Working Group within the IETF to focus its
efforts on "Resource Reservation Protocol (RSVP)-TE: Extensions to
RSVP for Label-Switched Paths (LSP) Tunnels" (RFC 3209) as the MPLS
signaling protocol for traffic engineering applications...
The P2MP TE LSP setup mechanism MUST include the ability to
add/remove egress LSRs to/from an existing P2MP TE LSP and MUST allow
for the support of all the TE LSP management procedures already
defined for P2P TE LSP such as the non disruptive rerouting (the so
called "Make before break" procedure).
The computation of P2MP TE trees is implementation dependent and is The computation of P2MP TE trees is implementation dependent and is
beyond the scope of the solutions that are built with this document beyond the scope of the solutions that are built with this document
as a guideline. as a guideline.
A separate document(s) will specify how to build P2MP TE LSPs. The A separate document(s) will specify how to build P2MP TE LSPs.
usage of those solutions will be application dependent and is out of The usage of those solutions will be application dependent and is
the scope of this document. However, it is a requirement that those out of the scope of this document. However, it is a requirement that
solutions be applicable to GMPLS as well as to MPLS so that only a those solutions attempt to be applicable to GMPLS as well as to MPLS
single set of solutions are developed. so that only a single set of solutions are developed.
Consider the following figure. Consider the following figure.
Source 1 (S1) Source 1 (S1)
| |
I-LSR1 I-LSR1
| | | |
| | | |
R2----E-LSR3--LSR1 LSR2---E-LSR2--Receiver 1 (R1) R2----E-LSR3--LSR1 LSR2---E-LSR2--Receiver 1 (R1)
| : | :
R3----E-LSR4 E-LSR5 R3----E-LSR4 E-LSR5
| : | :
| : | :
R4 R5 R4 R5
Figure 1 Figure 1
Figure 1 shows a single ingress (I-LSR1), and four egresses Figure 1 shows a single ingress (I-LSR1), and four egresses(E-LSR2,
(E-LSR2, E-LSR3, E-LSR4 and E-LSR5). I-LSR1 is attached to a traffic E-LSR3, E-LSR4 and E-LSR5). I-LSR1 is attached to a traffic source
source that is generating traffic for a P2MP application. that is generating traffic for a P2MP application.
Receivers R1, R2, R3 and R4 are attached to E-LSR2, E-LSR3 and Receivers R1, R2, R3 and R4 are attached to E-LSR2, E-LSR3 and
E-LSR4. E-LSR4.
The following are the objectives of P2MP LSP establishment and use. The following are the objectives of P2MP LSP establishment and use.
a) A P2MP TE LSP tree which satisfies various constraints is pre- a) A P2MP TE LSP tree which satisfies various constraints is
determined and supplied to ingress I-LSR1. pre-determined and supplied to ingress I-LSR1.
Note that no assumption is made on whether the tree is provided Note that no assumption is made on whether the tree is provided
to I-LSR1 or computed by I-LSR1. to I-LSR1 or computed by I-LSR1. Note that the solution SHOULD
also allow for the support of partial path by means of loose
routing.
Typical constraints are bandwidth requirements, resource class Typical constraints are bandwidth requirements, resource class
affinities, fast rerouting, preemption. There should not be any affinities, fast rerouting, preemption, to mention a few of
restriction on the possibility to support the set of them. There should not be any restriction on the possibility
constraints already defined for point to point TE LSPs. A new to support the set of constraints already defined for point to
constraint may specify which LSRs should be used as branch point TE LSPs. A new constraint may specify which LSRs should
points for the P2MP LSR in order to take into account some LSR be used as branch points for the P2MP LSR in order to take
capabilities or network constraints. into account some LSR capabilities or network constraints.
b) A P2MP TE LSP is set up by means of RSVP-TE from I-LSR1 to b) A P2MP TE LSP is set up from I-LSR1 to E-LSR2, E-LSR3 and
E-LSR2, E-LSR3 and E-LSR4 using the tree information. E-LSR4 using the tree information.
c) In this case, the branch LSR1 should replicate incoming packets c) In this case, the branch LSR1 should replicate incoming
or data and send them to E-LSR3 and E-LSR4. packets or data and send them to E-LSR3 and E-LSR4.
d) If a new receiver (R5) expresses an interest in receiving d) If a new receiver (R5) expresses an interest in receiving
traffic, a new tree is determined and a sub-P2MP tree from traffic, a new tree is determined and a sub-P2MP tree from
LSR2 to E-LSR5 is grafted onto the P2MP tree. LSR2 becomes LSR2 to E-LSR5 is grafted onto the P2MP tree. LSR2 becomes a
a branch LSR. branch LSR.
4. Application Specific Requirements 4. Examples of candidate applications that may require P2MP TE LSP
This section describes some of the applications that P2MP MPLS This section describes some of the candidate applications that P2MP
TE is applicable to along with application specific requirements. MPLS TE is applicable to.
The purpose of this section is not to mandate how P2MP TE LSPs must The purpose of this section is not to mandate how P2MP TE LSPs must
be used in certain application scenarios. Rather it is to illustrate be used in certain application scenarios. Rather it is to illustrate
some of the potential application scenarios so as to highlight some of the potential application scenarios so as to highlight the
the features and functions that any P2MP solution must provide in features and functions that any P2MP solution must provide in order
order to be of wide use and applicability. This section is not meant to be of wide use and applicability. This section is not meant to be
to be exhaustive, and P2MP is not limited to the described exhaustive, and P2MP is not limited to the described applications.
applications.
4.1 P2MP TE LSP for IP multicast data 4.1 P2MP TE LSP for IP multicast data
One typical scenario is to use P2MP TE LSPs as P2MP tunnels carrying One typical scenario is to use P2MP TE LSPs as P2MP tunnels carrying
multicast data traffic (e.g. IP mcast). In this scenario, a P2MP TE multicast data traffic (e.g. IP mcast). In this scenario, a P2MP TE
LSP is established between an ingress LSR which supports LSP is established between an ingress LSR which supports IP
IP multicast source and several egress LSRs which support several multicast source and several egress LSRs which support several IP
IP multicast receivers. Instead of using an IP multicast routing multicast receivers. A P2MP TE LSP is established over the network
protocol in the network core, a P2MP TE LSP is established over and IP multicast data are tunneled from an ingress LSR node to
the network and IP multicast data are tunneled from an ingress LSR multiple egress leaf LSRs with data replication at the branch LSRs
node to multiple egress leaf LSRs with data replication at the in the network core. Figure 2 shows an example.
branch LSRs in the network core. Figure 2 shows an example.
Note that a P2MP TE LSP can be established over multiple areas/ASs Note that a P2MP TE LSP can be established over multiple areas/ASs
and that the egress LSRs may deliver data into an IP multicast and that the egress LSRs may deliver data into an IP multicast
network. network.
Mcast Source Mcast Source
| |
+---------------I-LSR0----------------+ +---------------I-LSR0----------------+
| | | | | |
| LSR0 +----E-LSR2---R2 | LSR0 +----E-LSR2---R2
skipping to change at page 11, line 35 skipping to change at page 11, line 39
4.2 P2MP TE backbone network for IP multicast network 4.2 P2MP TE backbone network for IP multicast network
P2MP TE LSPs are applicable in a backbone network to construct or P2MP TE LSPs are applicable in a backbone network to construct or
support a multicast network(e.g. IPmcast network). support a multicast network(e.g. IPmcast network).
The IP multicast access networks are interconnected by P2MP TE LSPs. The IP multicast access networks are interconnected by P2MP TE LSPs.
A P2MP TE LSP is established from an ingress LSR which accommodates A P2MP TE LSP is established from an ingress LSR which accommodates
an IP multicast network that has a multicast source to multiple an IP multicast network that has a multicast source to multiple
egress LSRs which each accommodate an IP multicast network. egress LSRs which each accommodate an IP multicast network.
In this scenario, ingress/egress LSRs placed at the edge of multicast In this scenario, ingress/egress LSRs placed at the edge of
network must handle an IP multicast routing protocol. This means that multicast network handle an IP multicast routing protocol.
the ingress/egress LSRs exchange IP multicast routing messages as This means that the ingress/egress LSRs exchange IP multicast
neighbour routers. Figure 3 shows a network example of this scenario. routing messages as neighbor routers. Figure 3 shows a network
example of this scenario.
A P2MP TE LSP is established from a I-LSR1 to E-LSR2, E-LSR3, E-LSR4 A P2MP TE LSP is established from a I-LSR1 to E-LSR2, E-LSR3, E-LSR4
and the ingress/egress LSR exchanges the multicast routing messages and the ingress/egress LSR exchanges the multicast routing messages
with each other. with each other.
As specified in the section on the problem statement it should be As specified in the section related to the problem statement it
possible for a solution to add/remove egress LSRs to/from the should be possible for a solution to add/remove egress LSRs to/from
P2MP MPLS TE LSP. IP multicast group membership distribution between the P2MP MPLS TE LSP. IP multicast group membership distribution
the egress LSRs may change frequently. This in turn may require a between the egress LSRs may change frequently. This in turn may
potential P2MP MPLS TE solution, that is suitable for IP multicast, require a potential P2MP MPLS TE solution, that is suitable for IP
to handle additions/deletions of egress LSRs with an appropriate multicast, to handle additions/deletions of egress LSRs with an
reactiveness. appropriate reactiveness.
It is recommended to support a message exchange mechanism on top of It is recommended to support a message exchange mechanism on top of
P2MP LSP setup mechanism to support multicast (S, G) Join/Leave. P2MP LSP setup mechanism to support multicast (S, G) Join/Leave.
Though several schemes exist to handle this scenario, these are out Though several schemes exist to handle this scenario, these are out
of scope of this document. This document only describes requirements of scope of this document. This document only describes requirements
to setup a P2MP TE LSP. to setup a P2MP TE LSP.
Mcast Source Mcast Source
| |
skipping to change at page 12, line 38 skipping to change at page 13, line 7
R1---MR---MR || MR || MR__ | R1---MR---MR || MR || MR__ |
| / \ || / \ || / \ \MR---R8 | / \ || / \ || / \ \MR---R8
+--MR--MR--++----MR--MR---++--MR--MR--+ +--MR--MR--++----MR--MR---++--MR--MR--+
| | | | | | | | | | | |
R2 R3 R4 R5 R6 R7 R2 R3 R4 R5 R6 R7
Figure 3 Figure 3
4.3 Layer 2 Multicast Over MPLS 4.3 Layer 2 Multicast Over MPLS
Existing layer 2 networks offer multicast video services. These Existing layer 2 networks offer multicast video services. These are
are typically carried using layer 2 NBMA technology such as ATM typically carried using layer 2 NBMA technology such as ATM or
or layer 2 Broadcast Access technology such as Ethernet. It may be layer 2 Broadcast Access technology such as Ethernet. It may be
desirable to deliver these layer 2 multicast services over a desirable to deliver these layer 2 multicast services over
converged MPLS infrastructure where P2MP TE LSPs are used instead. a converged MPLS infrastructure where P2MP TE LSPs are used instead.
For instance, several SPs provision P2MP ATM VCs for TV/ADSL For instance, several SPs provision P2MP ATM VCs for TV/ADSL
services. These P2MP VCs are setup between a video server and a set services. These P2MP VCs are setup between a video server and a set
of ATM DSLAMs. Each channel is carried in a distinct P2MP VC. These of ATM DSLAMs. Each channel is carried in a distinct P2MP VC. These
VC maybe be routed independently, or may all be nested into a unique VC maybe be routed independently, or may all be nested into a unique
PVC, connecting the video sever to all DSLAMs. PVC, connecting the video sever to all DSLAMs.
Such service could benefit from a P2MP MPLS-TE control plane. An Such service could benefit from a P2MP MPLS-TE control plane. An
option is to setup a permanent P2MP TE LSP between the video server option is to setup a permanent P2MP TE LSP between the video server
and all DSLAMs, that would correspond to a PVC carrying all channel and all DSLAMs, that would correspond to a PVC carrying all channel
VCs. In this case each DSLAM receives all channels, even if there are VCs. In this case each DSLAM receives all channels, even if there
no receivers that are registered for a given channel. This ensure are no receivers that are registered for a given channel.
fast zapping, but lead to significant bandwidth wasting. This ensure fast zapping, but lead to significant bandwidth wasting.
A second option is to setup a distinct P2MP TE LSP per channel. If a A second option is to setup a distinct P2MP TE LSP per channel. If a
client, behind a DSLAM, zaps to a new channel, then the DSLAM has client, behind a DSLAM, zaps to a new channel, then the DSLAM has
to be added to the P2MP TE LSP carrying this channel using a P2MP TE to be added to the P2MP TE LSP carrying this channel using a P2MP TE
grafting procedure. Pruning procedure has to be used to remove a grafting procedure, if it is not already egress LSR for that LSP.
DSLAM from the P2MP TE LSP if it is not already egress LSR for that Pruning procedure has to be used to remove a DSLAM from the P2MP TE
LSP because all the clients, behind the DSLAM, stop watching the LSP when there is no longer any client behind the DSLAM, watching
channel. the channel.
4.4 VPN multicast network 4.4 VPN multicast network
In this scenario, P2MP TE LSPs are utilized to construct a provider In this scenario, P2MP TE LSPs could be utilized to construct a
network which can deliver VPN multicast service(s) to its customers. provider network which can deliver VPN multicast service(s) to its
customers.
A P2MP TE LSP is established between all the PE routers which A P2MP TE LSP is established between all the PE routers which
accommodate the customer private network(s) that handle the IP accommodate the customer private network(s) that handle the IP
multicast packets. Each PE router must handle a VPN instance. multicast packets. Each PE router must handle a VPN instance.
For example, in Layer3 VPNs like BGP/MPLS based IP VPNs For example, in Layer3 VPNs like BGP/MPLS based IP VPNs
[BGPMPLS-VPN], this means that each PE router must handle both [BGPMPLS-VPN], this means that each PE router must handle both
private multicast VRF tables and common multicast routing and private multicast VRF tables and common multicast routing and
forwarding table. And each PE router exchanges private multicast forwarding table. And each PE router exchanges private multicast
routing information between the corresponding PE routers. It is routing information between the corresponding PE routers. In case
desirable that P2MP MPLS TE can be used for Layer3 VPN data of high rate source, the need for P2MP TE LSP can be envisaged for
transmission. Layer3 VPN data transmission.
Another example is a Layer2 VPN that supports multipoint Another example is a Layer2 VPN that supports multipoint LAN
LAN connectivity service. In an Ethernet network environment, IP connectivity service. In an Ethernet network environment, IP
multicast data is flooded to the appropriate Ethernet port(s). multicast data is flooded to the appropriate Ethernet port(s).
An Ethernet multipoint Layer2 VPN service provided by MPLS, this An Ethernet multipoint Layer2 VPN service provided by MPLS, this
function is achieved by switching MPLS encapsulated frames towards function is achieved by switching MPLS encapsulated frames towards
the relevant PE nodes. But if existing P2P TE LSPs are used as the relevant PE nodes. But if existing P2P TE LSPs are used as
tunnels between PEs, any ingress PE must duplicate the frames and tunnels between PEs, any ingress PE must duplicate the frames and
send them to the corresponding PEs. This means the data stream is send them to the corresponding PEs. This means the data stream is
flooded just from the ingress PE, which will waste the provider's flooded just from the ingress PE, which will waste the provider's
network resources. network resources.
So, for Layer 2 VPNs that are required to support multicast traffic, So, for Layer 2 VPNs that are required to support multicast traffic,
it is desirable that P2MP MPLS TE LSPs are used for data transmission it might be desirable that P2MP MPLS TE LSPs are used for data
instead of P2P MPLS TE LSPs, contributing in turn to savings of transmission with an appropriate layer 2 encapsulation technique
network resources. (for example, pseudo wire) instead of P2P MPLS TE LSPs, contributing
in turn to savings of network resources.
This document does not set requirements for how multicast VPNs are This document does not set requirements for how multicast VPNs are
provided, but it does set requirements for the function that must be provided, but it does set requirements for the function that must be
available in P2MP MPLS solutions. Therefore, it is not a requirement available in P2MP MPLS solutions. Therefore, it is not a requirement
that multicast VPNs utilize P2MP MPLS, but it is a requirement that that multicast VPNs utilize P2MP TE LSPs, but it is a requirement
P2MP MPLS solutions should be capable of supporting multicast VPNs. that P2MP MPLS solutions should be capable of supporting multicast
VPNs.
As already pointed out, application-specific requirements are out of
the scope of this document.
4.5 GMPLS Networks 4.5 GMPLS Networks
GMPLS supports only P2P TE-LSPs just like MPLS. GMPLS enhances MPLS GMPLS currently supports only P2P TE-LSPs just like MPLS. GMPLS
to support four new classes of interfaces: Layer-2 Switch Capable enhances MPLS to support four new classes of interfaces: Layer-2
(L2SC), Time-Division Multiplex (TDM), Lambda Switch Capable (LSC) Switch Capable (L2SC), Time-Division Multiplex (TDM), Lambda Switch
and Fiber-Switch Capable (FSC) in addition to Packet Switch Capable Capable (LSC) and Fiber-Switch Capable (FSC) in addition to Packet
(PSC) already supported by MPLS. All of these interface classes have Switch Capable (PSC) already supported by MPLS. All of these
so far been limited to P2P TE LSPs (see [RFC 3473] and [RFC 3471]). interface classes have so far been limited to P2P TE LSPs
(see [RFC3473] and [RFC 3471]).
The requirement for P2MP services for non-packet switch interfaces The requirement for P2MP services for non-packet switch interfaces
is similar to that for PSC interfaces. In particular, cable is similar to that for PSC interfaces. In particular, cable
distribution services such as video distribution are prime candidates distribution services such as video distribution are prime
to use P2MP features. Therefore, it is a requirement that all the candidates to use P2MP features. Therefore, it is a requirement that
features/mechanisms (and protocol extensions) that will be defined to reasonable attempts must be made to make all the features/mechanisms
provide MPLS P2MP TE LSPs will be equally applicable to P2MP PSC and (and protocol extensions) that will be defined to provide MPLS P2MP
non-PSC TE-LSPs. TE LSPs equally applicable to P2MP PSC and non-PSC TE-LSPs. If the
requirements of non-PSC networks over-complicate the PSC solution a
decision may be taken to separate the solutions. This decision must
be taken in full consultation with the MPLS and CCAMP working
groups.
5. Detailed requirements for P2MP TE extensions 5. Detailed requirements for P2MP TE extensions
5.1 P2MP LSP tunnels 5.1 P2MP LSP tunnels
The P2MP RSVP-TE extensions MUST be applicable to signaling LSPs The P2MP TE extensions MUST be applicable to the signaling of LSPs
of different traffic types. For example, it MUST be possible to of different traffic types. For example, it MUST be possible to
signal a P2MP TE LSP to carry any kind of payload being packet or signal a P2MP TE LSP to carry any kind of payload being packet or
non-packet based (including frame, cell, TDM un/structured, etc.) non-packet based (including frame, cell, TDM un/structured, etc.)
Carrying IP multicast or Ethernet traffic within a P2MP tunnel are Carrying IP multicast or Ethernet traffic within a P2MP tunnel are
typical examples. typical examples.
As with P2P MPLS technology [RFC3031], traffic is classified with a As with P2P MPLS technology [RFC3031], traffic is classified with a
FEC in this extension. All packets which belong to a particular FEC FEC in this extension. All packets which belong to a particular FEC
and which travel from a particular node MUST follow the same P2MP and which travel from a particular node MUST follow the same P2MP
tree. tree.
skipping to change at page 15, line 34 skipping to change at page 16, line 18
| / \ / \ | / \ / \
C D E F G C D E F G
| / \ / \/ \ / \ | / \ / \/ \ / \
D--E*-F*-G*-H*-I*-J*-K*--L H I J KL M N O D--E*-F*-G*-H*-I*-J*-K*--L H I J KL M N O
Steiner P2MP tree SPF P2MP tree Steiner P2MP tree SPF P2MP tree
Figure 4 Examples of P2MP TE LSP topology Figure 4 Examples of P2MP TE LSP topology
One example is the Steiner P2MP tree (Cost minimum P2MP tree) One example is the Steiner P2MP tree (Cost minimum P2MP tree)
[STEINER]. This P2MP tree is suitable for constructing a cost minimum [STEINER]. This P2MP tree is suitable for constructing a cost
P2MP tree. To realize this P2MP tree, several intermediate LSRs must minimum P2MP tree so as to minimize the bandwidth consumption in
be both MPLS data terminating LSRs and transit LSRs (LSRs E, F, G, H, the core. To realize this P2MP tree, several intermediate LSRs must
I, J and K in the figure 4). This means that the LSRs must perform be both MPLS data terminating LSRs and transit LSRs (LSRs E, F, G,
both label swapping and popping at the same time. Therefore, the P2MP H, I, J and K in the figure 4). This means that the LSRs must
TE solution MUST support a mechanism that can setup this kind of perform both label swapping and popping at the same time. Therefore,
bud LSR between an ingress LSR and egress LSRs. the P2MP TE solution MUST support a mechanism that can setup this
kind of bud LSR between an ingress LSR and egress LSRs. Note that
this includes constrained Steiner trees that allow for the
computation of a minimal cost trees with some other constraints such
as a bounded delay between the source and every receiver.
Another example is a CSPF (Constraint Shortest Path Fast) P2MP tree. Another example is a CSPF (Constraint Shortest Path First) P2MP
By some metric (which can be set upon any specific criteria like the tree. By some metric (which can be set upon any specific criteria
delay, bandwidth, a combination of those), one can calculate a cost like the delay, bandwidth, a combination of those), one can
minimum P2MP tree. This P2MP tree is suitable for carrying real time calculate a shortest path P2MP tree. This P2MP tree is suitable for
traffic. carrying real time traffic.
The solution MUST allow the operator to make use of any tree
computation technique. In the former case an efficient/optimal tree
is defined as a minimal cost tree (Steiner tree) whereas in the
later case it is defined as the tree that provides shortest path
between the source and any receiver.
To support explicit setup of any reasonable P2MP tree shape, a P2MP To support explicit setup of any reasonable P2MP tree shape, a P2MP
TE solution MUST support some form of explicit source-based control TE solution MUST support some form of explicit source-based control
of the P2MP tree which can explicitly include particular LSRs as of the P2MP tree which can explicitly include particular LSRs as
branch nodes. This can be used by the ingress LSR to setup the P2MP branch nodes. This can be used by the ingress LSR to setup the P2MP
TE LSP. Being implementation specific (more precisely dependent on TE LSP. For instance, a P2MP TE LSP can be simply represented as a
the data structure specific representation and its processing), the
detailed method for controlling the P2MP TE LSP topology depends on
how the control plane represents the P2MP TE LSP data plane entity.
For instance, a P2MP TE LSP can be simply represented as a
whole tree or by its individual branches. whole tree or by its individual branches.
Here the effectiveness of the potential solutions is left outside
the scope of this document. In any case, it is expected that this
control must be driven by the ingress LSR.
5.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes 5.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes
A P2MP tree is completely specified if all of the required A P2MP tree is completely specified if all of the required branches
branches and hops between a sender and leaf LSR are indicated. and hops between a sender and leaf LSR are indicated.
A P2MP tree is partially specified if only a subset of intermediate A P2MP tree is partially specified if only a subset of intermediate
branches and hops are indicated. This may be achieved using branches and hops are indicated. This may be achieved using loose
loose hops in the explicit path, or using widely scoped abstract hops in the explicit path, or using widely scoped abstract nodes
nodes such as IPv4 prefixes shorter than 32 bits, or AS numbers. such as IPv4 prefixes shorter than 32 bits, or AS numbers.
A partially specified P2MP tree may be particularly useful in A partially specified P2MP tree might be particularly useful in
inter-area and inter-AS situations. inter-area and inter-AS situations although P2MP requirements for
inter-area and inter-AS are beyond the scope of this document.
Protocol solutions SHOULD include a way to specify loose Protocol solutions SHOULD include a way to specify loose hops and
hops and widely scoped abstract nodes in the explicit source- widely scoped abstract nodes in the explicit source-based control
based control of the P2MP tree as defined in the previous of the P2MP tree as defined in the previous section. Where this
section. Where this support is provided, protocol solutions support is provided, protocol solutions MUST allow downstream LSRs
MUST allow downstream LSRs to apply further explicit to apply further explicit control to the P2MP tree to resolve a
control to the P2MP tree to resolve a partially specified tree partially specified tree into a (more) completely specified tree.
into a (more) completely specified tree.
Protocol solutions MUST allow the P2MP tree to be completely Protocol solutions MUST allow the P2MP tree to be completely
specified at the ingress where sufficient information exists to allow specified at the ingress where sufficient information exists to
the full tree to be computed. allow the full tree to be computed.
In all cases, the egress nodes of the P2MP TE LSP must be fully In all cases, the egress nodes of the P2MP TE LSP must be fully
specified. specified.
In case of a tree being computed by some downstream LSRs (e.g. the In case of a tree being computed by some downstream LSRs (e.g. the
case of hops specified as loose hops), the solution MUST provide the case of hops specified as loose hops), the solution MUST provide
ability for the ingress LSR of the P2MP TE LSP to learn the full the ability for the ingress LSR of the P2MP TE LSP to learn the full
P2MP tree. Note that this requirement MAY be relaxed in some P2MP tree. Note that this requirement MAY be relaxed in some
environments (e.g. Inter-AS) where confidentiality must be preserved. environments (e.g. Inter-AS) where confidentiality must be preserved.
5.4 P2MP TE LSP establishment, teardown, and modification mechanisms 5.4 P2MP TE LSP establishment, teardown, and modification mechanisms
The P2MP TE solution MUST support large scale P2MP TE LSPs The P2MP TE solution MUST support establishment, maintenance and
establishment and teardown in a scalable manner. teardown of P2MP TE LSPs in a scalable manner. This MUST include
both the existence of very many LSPs at once, and the existence of
very many destinations for a single P2MP LSP.
In addition to P2MP TE LSP establishment and teardown mechanism, In addition to P2MP TE LSP establishment and teardown mechanism, it
it SHOULD implement partial P2MP tree modification mechanism. SHOULD implement partial P2MP tree modification mechanism.
For the purpose of adding sub-P2MP TE LSPs to an existing P2MP TE For the purpose of adding sub-P2MP TE LSPs to an existing P2MP TE
LSP, the extensions SHOULD support a grafting mechanism. For the LSP, the extensions SHOULD support a grafting mechanism. For the
purpose of deleting a sub-P2MP TE LSPs from an existing P2MP TE purpose of deleting a sub-P2MP TE LSPs from an existing P2MP TE LSP,
LSP, the extensions SHOULD support a pruning mechanism. the extensions SHOULD support a pruning mechanism.
It is RECOMMENDED that these grafting and pruning operations do not It is RECOMMENDED that these grafting and pruning operations do not
cause any additional processing in nodes except along the path to the cause any additional processing in nodes except along the path to
grafting and pruning node and its downstream nodes. Moreover, both the grafting and pruning node and its downstream nodes. Moreover,
grafting and pruning operations MUST not be traffic disruptive for both grafting and pruning operations MUST not be traffic disruptive
the traffic currently forwarded along the P2MP tree. for the traffic currently forwarded along the P2MP tree.
5.5 Failure Reporting and Error Recovery 5.5 Fragmentation
The P2MP TE solution MUST handle the situation where a single
protocol message cannot contain all of the information necessary to
signal the establishment of the P2MP LSP. It MUST be possible to
establish the LSP in these circumstances.
This situation may arrise in either of the following circumstances.
a. The ingress LSR cannot signal the whole tree in a single
message.
b. The information in a message expands to be too large (or is
discovered to be too large) at some transit node. This may
occur because of some increase in the information that needs
to be signaled or because of a reduction in the size of
signaling message that is supported.
5.6 Failure Reporting and Error Recovery
Failure events may cause egress nodes or sub-P2MP LSPs to become Failure events may cause egress nodes or sub-P2MP LSPs to become
detached from the P2MP TE LSP. These events MUST be reported upstream detached from the P2MP TE LSP. These events MUST be reported
as for a P2P LSP. upstream as for a P2P LSP.
The solution SHOULD provide recovery techniques such as protection The solution SHOULD provide recovery techniques such as protection
and restoration allowing recovery of any impacted sub-P2MP TE LSPs. and restoration allowing recovery of any impacted sub-P2MP TE
In particular, a solution MUST provide fast protection mechanisms LSPs. In particular, a solution MUST provide fast protection
applicable to P2MP TE LSP similar to the solutions specified in [FRR] mechanisms applicable to P2MP TE LSP similar to the solutions
for P2P TE LSPs. Note also that no assumption is made on whether specified in [FRR] for P2P TE LSPs. Note also that no assumption is
backup paths for P2MP TE LSPs should or should not be shared with P2P made on whether backup paths for P2MP TE LSPs should or should not
TE LSPs backup paths. be shared with P2P TE LSPs backup paths.
A P2MP TE solution MUST support P2MP fast protection mechanism Note that other application-specific requirement documents may
to handle P2MP applications sensitive to traffic disruption. introduce even more stringent requirement such as non packet loss,
at the cost of some increased bandwidth consumption.
The report of the failure of delivery to fewer than all of the egress The solution SHOULD also support the ability to meet other network
nodes SHOULD NOT cause automatic teardown of the P2MP TE LSP. recovery requirements such as bandwidth protection and bounded
That is, while some egress nodes remain connected to the P2MP tree it propagation delay increase along the backup path during failure.
should be a matter of local policy at the ingress whether the P2MP
LSP is retained.
When all egress nodes downstreams of a branch node have become A P2MP TE solution MUST support P2MP fast protection mechanism to
handle P2MP applications sensitive to traffic disruption.
The report of the failure of delivery to fewer than all of the
egress nodes SHOULD NOT cause automatic teardown of the P2MP TE LSP.
That is, while some egress nodes remain connected to the P2MP tree
it should be a matter of local policy at the ingress whether the
P2MP LSP is retained.
When all egress nodes downstream of a branch node have become
disconnected from the P2MP tree, and the some branch node is unable disconnected from the P2MP tree, and the some branch node is unable
to restore connectivity to any of them through recovery or protection to restore connectivity to any of them by means of some recovery or
mechanisms, the branch node MAY remove itself from the P2MP tree. protection mechanisms, the branch node MAY remove itself from the
Since the faults that severed the various downstream egress nodes P2MP tree provided that it is not also an egress LSR. Since the
from the P2MP tree may be disparate, the branch node MUST report all faults that severed the various downstream egress nodes from the
such errors to its upstream neighbor. The ingress node can then P2MP tree may be disparate, the branch node MUST report all such
decide to re-compute the path to those particular egress nodes, errors to its upstream neighbor. The ingress node can then decide
around the failure point. to re-compute the path to those particular egress nodes, around the
failure point.
Solutions MAY include the facility for transit LSRs and particularly Solutions MAY include the facility for transit LSRs and particularly
branch nodes to recompute sub-P2MP trees to restore them after branch nodes to recompute sub-P2MP trees to restore them after
failures. In the event of successful repair, error notifications failures. In the event of successful repair, error notifications
SHOULD NOT be reported to upstream nodes, but the new paths are SHOULD NOT be reported to upstream nodes, but the new paths are
reported if route recording is in use. Crankback requirements are reported if route recording is in use. Crankback requirements are
discussed in Section 5.18. discussed in Section 5.18.
5.6 Record route of P2MP TE LSP tunnels 5.7 Record route of P2MP TE LSP tunnels
Being able to identify the established topology of P2MP TE LSP is Being able to identify the established topology of P2MP TE LSP is
very important for various purposes such as management and operation very important for various purposes such as management and operation
of some local recovery mechanisms like Fast Reroute [FRR]. A network of some local recovery mechanisms like Fast Reroute [FRR]. A network
operator uses this information to manage P2MP TE LSPs. Therefore, operator uses this information to manage P2MP TE LSPs. Therefore,
topology information MUST be collected and updated after P2MP TE LSP topology information MUST be collected and updated after P2MP TE LSP
establishment and modification process. establishment and modification process.
For this purpose, the conventional Record Route mechanism is useful. The P2MP TE solution MUST support a mechanism which can collect and
As with other conventional mechanism, this information should be update P2MP tree topology information after P2MP LSP establishment
forwarded upstream towards the sender node. The P2MP TE solution MUST and modification process. For example, the P2P MPLS TE mechanism of
support a mechanism which can collect and update P2MP tree topology route recording could be extended and used if RSVP-TE was used as
information after P2MP LSP establishment and modification process. the P2MP signaling protocol.
It is RECOMMENDED that the information is collected in a data It is RECOMMENDED that the information is collected in a data format
format by which the sender node can recognize the P2MP tree topology by which the sender node can recognize the P2MP tree topology
without involving some complicated data calculation process. without involving some complicated data calculation process.
The solution MUST support the recording of both outgoing interfaces The solution MUST support the recording of both outgoing interfaces
and node-id [NODE-ID]. and node-id [NODE-ID].
5.7 Call Admission Control (CAC) and QoS Control mechanism 5.8 Call Admission Control (CAC) and QoS Control mechanism
of P2MP TE LSP tunnels of P2MP TE LSPs
P2MP TE LSPs may share network resource with P2P TE LSPs. Therefore P2MP TE LSPs may share network resource with P2P TE LSPs. Therefore
it is important to use CAC and QoS in the same way as P2P TE LSPs it is important to use CAC and QoS in the same way as P2P TE LSPs
for easy and scalable operation. for easy and scalable operation.
In particular, it should be highlighted that because Multicast In particular, it should be highlighted that because Multicast
traffic cannot make use of P2P TE LSP, multicast traffic cannot be traffic cannot make use of P2P TE LSP, multicast traffic cannot be
easily taken into account by P2P TE LSPs when performing CAC. easily taken into account by P2P TE LSPs when performing CAC.
The use of P2MP TE LSP will now allow for an accounting of the The use of P2MP TE LSP will now allow for an accounting of the
unicast and multicast traffic for bandwidth reservation. unicast and multicast traffic for bandwidth reservation.
P2MP TE solutions MUST support both FF and SE reservation styles. P2MP TE solutions MUST support both resource sharing and exclusive
resource utilization to facilitate co-existence with other LSPs to
the same destination(s).
P2MP TE solution MUST be applicable to Diffserv-enabled networks P2MP TE solution MUST be applicable to DiffServ-enabled networks
that can provide consistent QoS control in P2MP LSP traffic. that can provide consistent QoS control in P2MP LSP traffic.
Any solution SHOULD also satisfy the DS-TE requirements [RFC3564] and Any solution SHOULD also satisfy the DS-TE requirements [RFC3564]
interoperate smoothly with current P2P DS-TE protocol specifications. and interoperate smoothly with current P2P DS-TE protocol
specifications.
Note that this requirement document does not make any assumption on Note that this requirement document does not make any assumption on
the type of bandwidth pool used for P2MP TE LSPs which can either be the type of bandwidth pool used for P2MP TE LSPs which can either be
shared with P2P TE LSP or be dedicated for P2MP use. shared with P2P TE LSP or be dedicated for P2MP use.
5.8 Reoptimization of P2MP TE LSP 5.9 Reoptimization of P2MP TE LSP
The detection of a more optimal path is an example of a situation The detection of a more optimal path (for example, one with a lower
where P2MP TE LSP re-routing may be required. While re-routing is in overall cost) is an example of a situation where P2MP TE LSP
progress, an important requirement is avoiding double bandwidth re-routing may be required. While re-routing is in progress, an
reservation (over the common parts between the old and new LSP) important requirement is avoiding double bandwidth reservation
thorough the use of resource sharing. Make-before-break (over the common parts between the old and new LSP) thorough the use
(see [RFC3209]) delivers simultaneously a solution to these of resource sharing.
requirements.
Make-before-break MUST be supported for a P2MP TE LSP to ensure that Make-before-break MUST be supported for a P2MP TE LSP to ensure that
there is no traffic disruption when the P2MP TE LSP is re-routed. there is no traffic disruption when the P2MP TE LSP is re-routed.
For example, the P2P MPLS TE make-before-break mechanism could be
extended and used if RSVP-TE was used as the P2MP signaling protocol.
It is possibile to achieve make-before-break that only It is possible to achieve make-before-break that only applies to a
applies to a sub-P2MP tree without impacting the data on all of sub-P2MP tree without impacting the data on all of the other parts
the other parts of the P2MP tree. of the P2MP tree.
The solution SHOULD allow for make-before-break reoptimization of The solution SHOULD allow for make-before-break reoptimization of a
a sub-tree with no impact on the rest of the tree (no label sub-tree with no impact on the rest of the tree (no label
reallocation, no change in identifiers, etc.). reallocation, no change in identifiers, etc.).
The solution SHOULD also provide the ability for the ingress LSR The solution SHOULD also provide the ability for the ingress LSR to
to have a strict control on the reoptimization process. have a strict control on the reoptimization process.
Such reoptimization MAY be initiated by the sub-tree root branch Such reoptimization MAY be initiated by the sub-tree root branch
node (that is, the branch node MAY setup a new sub-tree, then splice node (that is, the branch node MAY setup a new sub-tree, then splice
traffic on the new subtree and delete the former sub-tree). traffic on the new subtree and delete the former sub-tree).
5.9 IPv4/IPv6 support 5.10 IPv4/IPv6 support
Any P2MP TE solution MUST be equally applicable to IPv4 and IPv6. Any P2MP TE solution MUST be equally applicable to IPv4 and IPv6.
5.10 P2MP MPLS Label 5.11 P2MP MPLS Label
A P2MP TE solution MUST support establishment of both P2P and A P2MP TE solution MUST support establishment of both P2P and P2MP
P2MP TE LSPs and MUST NOT impede the operation of P2P TE LSPs within TE LSPs and MUST NOT impede the operation of P2P TE LSPs within the
the same network. A P2MP TE solution MUST be specified in such same network. A P2MP TE solution MUST be specified in such a way
a way that it allows P2MP and P2P TE LSPs to be signaled on the that it allows P2MP and P2P TE LSPs to be signaled on the same
same interface. Labels for P2MP TE LSPs and P2P TE LSPs MAY be interface. Labels for P2MP TE LSPs and P2P TE LSPs MAY be assigned
assigned from shared or dedicated label space(s). Label space from shared or dedicated label space(s). Label space shareability is
shareability is implementation specific. implementation specific.
5.11 Routing advertisement of P2MP capability 5.12 Routing advertisement of P2MP capability
Several high-level requirements have been identified to determine Several high-level requirements have been identified to determine
the capabilities of LSRs within a P2MP network. This information is the capabilities of LSRs within a P2MP network. The aim of such
to facilitate the computation of P2MP trees using TE constraints information is to facilitate the computation of P2MP trees using TE
within a network that contains LSRs that do not all have the same constraints within a network that contains LSRs that do not all have
capabilities levels with respect to P2MP signaling and data the same capabilities levels with respect to P2MP signaling and data
forwarding. forwarding.
These capabilities include, but are not limited to: These capabilities include, but are not limited to:
- the ability of an LSR to support branching. - the ability of an LSR to support branching.
- the ability of an LSR to act as an egress and a branch for the - the ability of an LSR to act as an egress and a branch for the
same LSP. same LSP.
- the ability of an LSR to support P2MP MPLS-TE signalling.
It is expected that it may be appropriate to gather this information It is expected that it may be appropriate to gather this information
through extensions to TE IGPs (see [RFC3630] and [IS-IS-TE]), but the through extensions to TE IGPs (see [RFC3630] and [IS-IS-TE]), but
precise requirements and mechanisms are out of the scope of this the precise requirements and mechanisms are out of the scope of this
document. It is expected that a separate document will cover this document. It is expected that a separate document will cover this
requirement. requirement.
5.12 Multi-Area/AS LSP 5.13 Multi-Area/AS LSP
P2MP TE solutions SHOULD support multi-area/AS P2MP LSPs. P2MP TE solutions SHOULD support multi-area/AS P2MP TE LSPs.
The precise requirements in support of multi-area/AS P2MP LSPs The precise requirements in support of multi-area/AS P2MP TE LSPs is
is out of the scope of this document. It is expected that a separate out of the scope of this document. It is expected that a separate
document will cover this requirement. document will cover this requirement.
5.13 P2MP MPLS OAM 5.14 P2MP MPLS OAM
Management of P2MP LSPs is as important as the management of P2P Management of P2MP LSPs is as important as the management of P2P
LSPs. LSPs.
The MPLS and GMPLS MIB modules MUST be enhanced to provide P2MP TE The MPLS and GMPLS MIB modules MUST be enhanced to provide P2MP TE
LSP management. LSP management.
In order to facilitate correct management, P2MP TE LSPs MUST have In order to facilitate correct management, P2MP TE LSPs MUST have
unique identifiers. unique identifiers.
OAM facilities will have special demands in P2MP environments OAM facilities will have special demands in P2MP environments
especially within the context of tracing the paths and connectivity especially within the context of tracing the paths and connectivity
of P2MP TE LSPs. The precise requirements and mechanisms for OAM are of P2MP TE LSPs. The precise requirements and mechanisms for OAM are
out of the scope of this document. It is expected that a separate out of the scope of this document. It is expected that a separate
document will cover these requirements. document will cover these requirements.
5.14 Scalability 5.15 Scalability
Scalability is a key requirement in P2MP MPLS systems. Solutions Scalability is a key requirement in P2MP MPLS systems. Solutions
MUST be designed to scale well with an increase in the number of MUST be designed to scale well with an increase in the number of any
any of the following: of the following:
- the number of recipients - the number of recipients
- the number of branch points - the number of branch points
- the number of branches. - the number of branches.
Both scalability of performance and operation MUST be considered. Both scalability of performance and operation MUST be considered.
Key considerations SHOULD include: Key considerations SHOULD include:
- the amount of refresh processing associated with maintaining a - the amount of refresh processing associated with maintaining
P2MP TE LSP. a P2MP TE LSP.
- the amount of protocol state that must be maintained by ingress - the amount of protocol state that must be maintained by ingress
and transit LSRs along a P2MP tree. and transit LSRs along a P2MP tree.
- the number of protocol messages required to set up or tear down - the number of protocol messages required to set up or tear down a
a P2MP LSP as a function of the number of egress LSRs. P2MP LSP as a function of the number of egress LSRs.
- the number of protocol messages required to repair a P2MP LSP - the number of protocol messages required to repair a P2MP LSP
after failure or perform make-before-break. after failure or perform make-before-break.
- the amount of protocol information transmitted to manage a P2MP - the amount of protocol information transmitted to manage
TE LSP (i.e. the message size). a P2MP TE LSP (i.e. the message size).
- the amount of potential routing extensions. - the amount of potential routing extensions.
- the amount of control plane processing required by the ingress, - the amount of control plane processing required by the ingress,
transit and egress LSRs to add/delete a branch LSP to/from an transit and egress LSRs to add/delete a branch LSP to/from an
existing P2MP LSP. existing P2MP LSP.
5.15 Backwards Compatibility It is expected that the applicability of each solution will be
evaluated with regards to the aforementioned scalability criteria.
5.16 Backwards Compatibility
It SHOULD be an aim of any P2MP solution to offer as much backward It SHOULD be an aim of any P2MP solution to offer as much backward
compatibility as possible. An ideal would be to offer P2MP services compatibility as possible. An ideal which is probably impossible to
across legacy MPLS networks without any change to any LSR in the
network. achieve would be to offer P2MP services across legacy MPLS networks
without any change to any LSR in the network.
If this ideal cannot be achieved, the aim SHOULD be to use legacy If this ideal cannot be achieved, the aim SHOULD be to use legacy
nodes as both transit non-branch LSRs and egress LSRs. nodes as both transit non-branch LSRs and egress LSRs.
It is a further requirement of all protocol solutions that any LSR It is a further requirement for the solution that any LSR that
that implements the solution SHALL NOT be prohibited by that act from implements the solution SHALL NOT be prohibited by that act from
supporting P2P TE LSPs using existing signaling mechanisms. That is, supporting P2P TE LSPs using existing signaling mechanisms. That is,
unless administratively prohibited, P2P TE LSPs MUST be supported unless administratively prohibited, P2P TE LSPs MUST be supported
through a P2MP network. through a P2MP network.
5.16 GMPLS Also, it is a requirement that P2MP TE LSPs MUST be able to co-exist
with IP unicast and IP multicast networks.
Solutions for MPLS P2MP TE-LSPs when applied to GMPLS P2MP PSC 5.17 GMPLS
or non-PSC TE-LSPs MUST be backward and forward compatible with
the other features of GMPLS including:
- control and data plane separation (IF_ID RSVP_HOP and Solutions for MPLS P2MP TE-LSPs when applied to GMPLS P2MP PSC or
IF_ID ERROR_SPEC), non-PSC TE-LSPs MUST be backward and forward compatible with the
other features of GMPLS including:
- control and data plane separation (IF_ID RSVP_HOP and IF_ID
ERROR_SPEC),
- full support of numbered and unnumbered TE links (see [RFC 3477] - full support of numbered and unnumbered TE links (see [RFC 3477]
and [GMPLS-ROUTE]), and [GMPLS-ROUTE]),
- use of the GENERALIZED_LABEL_REQUEST and the GENERALIZED_LABEL - use of the GENERALIZED_LABEL_REQUEST, the GENERALIZED_LABEL
(C-Type 2 and 3) in conjunction with the LABEL_SET and the (C-Type 2 and 3), the SUGGESTED_LABEL and the RECOVERY_LABEL,
ACCEPTABLE_LABEL_SET object, in conjunction with the LABEL_SET and the ACCEPTABLE_LABEL_SET
object,
- processing of the ADMIN_STATUS object, - processing of the ADMIN_STATUS object,
- processing of the PROTECTION object, - processing of the PROTECTION object,
- support of Explicit Label Control, - support of Explicit Label Control,
- processing of the Path_State_Removed Flag, - processing of the Path_State_Removed Flag,
- handling of Graceful Deletion procedures. - handling of Graceful Deletion procedures.
- E2E and Segment Recovery procedures.
In addition, since non-PSC TE-LSPs may have to be processed in In addition, since non-PSC TE-LSPs may have to be processed in
environments where the "P2MP capability" could be limited, specific environments where the "P2MP capability" could be limited, specific
constraints may also apply during the P2MP TE Path computation. constraints may also apply during the P2MP TE Path computation.
Being technology specific, these constraints are outside the scope Being technology specific, these constraints are outside the scope
of this document. However, technology independent constraints (i.e. of this document. However, technology independent constraints
constraints that are applicable independently of the LSP class) (i.e. constraints that are applicable independently of the LSP
SHOULD be allowed during P2MP TE LSP message processing. It has to class) SHOULD be allowed during P2MP TE LSP message processing.
be emphasized that path computation and management techniques shall It has to be emphasized that path computation and management
be as close as possible to those being used for PSC P2P TE LSPs techniques shall be as close as possible to those being used for
and P2MP TE LSPs. PSC P2P TE LSPs and P2MP TE LSPs.
Finally, note that bi-directional TE LSPs are not applicable to
multicast traffic. Although many leaf nodes may be considered as
senders in a multicast group, a P2MP TE LSP models a single
distribution tree from a sender to multiple recipients. If such
a tree were made bi-directional it would be a multipoint-to-point
tree in the reverse direction.
5.17 Requirements for Hierarchical P2MP TE LSPs 5.18 Requirements for Hierarchical P2MP TE LSPs
[LSP-HIER] defines concepts and procedures for P2P LSP hierarchy. [LSP-HIER] defines concepts and procedures for P2P LSP hierarchy.
These procedures SHOULD be extended to support P2MP LSP hierarchy. These procedures SHOULD be extended to support P2MP LSP hierarchy.
The P2MP MPLS-TE solution SHOULD support the concept of region and The P2MP MPLS-TE solution SHOULD support the concept of region and
region hierarchy (PSC1<PSC2<PSC3<PSC4<L2SC<TDM<LSC<FSC). region hierarchy (PSC1<PSC2<PSC3<PSC4<L2SC<TDM<LSC<FSC).
Particularly it SHOULD allow a Region i P2MP TE LSP to be nested Particularly it SHOULD allow a Region i P2MP TE LSP to be nested
into a region j P2MP TE LSP or multiple region j P2P TE LSPs, into a region j P2MP TE LSP or multiple region j P2P TE LSPs,
providing that i<j. providing that i<j.
The precise requirements and mechanisms for this function are out of The precise requirements and mechanisms for this function are out of
the scope of this document. It is expected that a separate document the scope of this document. It is expected that a separate document
will cover these requirements. will cover these requirements.
5.18 P2MP Crankback routing 5.19 P2MP Crankback routing
P2MP solutions SHOULD support cranckback requirements as defined in P2MP solutions SHOULD support crankback requirements as defined in
[CRANKBACK]. In particular, they SHOULD provide sufficient [CRANKBACK]. In particular, they SHOULD provide sufficient
information to a branch LSR from downstream LSRs to allow the branch information to a branch LSR from downstream LSRs to allow the branch
LSR to re-route a sub-tree around any failures or problems in the LSR to re-route a sub-tree around any failures or problems in the
network. network.
6. Security Considerations 6. Security Considerations
This requirements document does not define any protocol extensions This requirements document does not define any protocol extensions
and does not, therefore, make any changes to any security models. and does not, therefore, make any changes to any security models.
skipping to change at page 23, line 43 skipping to change at page 25, line 7
techniques and problems associated with RSVP-TE. These problems may techniques and problems associated with RSVP-TE. These problems may
be exacerbated in P2MP situations where security relationships may be exacerbated in P2MP situations where security relationships may
need to maintained between an ingress and multiple egresses. Such need to maintained between an ingress and multiple egresses. Such
issues are similar to security issues for IP multicast. issues are similar to security issues for IP multicast.
It is a requirement that documents offering solutions for P2MP LSPs It is a requirement that documents offering solutions for P2MP LSPs
MUST have detailed security sections. MUST have detailed security sections.
7. Acknowledgements 7. Acknowledgements
The authors would like to thank George Swallow, Ichiro Inoue and The authors would like to thank George Swallow, Ichiro Inoue, Dean
Dean Cheng for their review and suggestions on an earlier draft of Cheng, and Eric Rosen for their review and suggestions.
this document.
8. References 8. References
8.1 Normative References 8.1 Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z. [RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.
and W. Weiss, "An Architecture for Differentiated and W. Weiss, "An Architecture for Differentiated
skipping to change at page 25, line 37 skipping to change at page 26, line 48
Switching", draft-ietf-ccamp-gmpls-routing-08.txt, Switching", draft-ietf-ccamp-gmpls-routing-08.txt,
October 2003. October 2003.
[STEINER] H. Salama, et al., "Evaluation of Multicast Routing [STEINER] H. Salama, et al., "Evaluation of Multicast Routing
Algorithm for Real-Time Communication on High-Speed Algorithm for Real-Time Communication on High-Speed
Networks," IEEE Journal on Selected Area in Networks," IEEE Journal on Selected Area in
Communications, pp.332-345, 1997. Communications, pp.332-345, 1997.
[FRR] P. Pan, D. Gan, G. Swallow, J. P. Vasseur, D. Cooper, [FRR] P. Pan, D. Gan, G. Swallow, J. P. Vasseur, D. Cooper,
A. Atlas, M. Jork,"Fast Reroute Extensions to RSVP-TE A. Atlas, M. Jork,"Fast Reroute Extensions to RSVP-TE
for LSP Tunnels", draft-ietf-mpls-rsvp-lsp-fastreroute- for LSP Tunnels",
03.txt, July 2003. draft-ietf-mpls-rsvp-lsp-fastreroute-03.txt, July
2003.
[IS-IS-TE] Henk Smit, Tony Li, "IS-IS extensions for Traffic [IS-IS-TE] Henk Smit, Tony Li, "IS-IS extensions for Traffic
Engineering", draft-ietf-isis-traffic-04.txt, December Engineering", draft-ietf-isis-traffic-04.txt, December
2002. 2002.
[CRANKBACK] A. Farrel, A. Satyanarayana, A. Iwata, N. Fujita, G. [CRANKBACK] A. Farrel, A. Satyanarayana, A. Iwata, N. Fujita, G.
Ash, S. Marshall, "Crankback Signaling Extensions for Ash, S. Marshall, "Crankback Signaling Extensions for
MPLS Signaling", draft-ietf-ccamp-crankback-01.txt, MPLS Signaling", draft-ietf-ccamp-crankback-01.txt,
January 2004. January 2004.
skipping to change at page 28, line 17 skipping to change at page 29, line 33
The IETF invites any interested party to bring to its attention The IETF invites any interested party to bring to its attention
any copyrights, patents or patent applications, or other any copyrights, patents or patent applications, or other
proprietary rights that may cover technology that may be required proprietary rights that may cover technology that may be required
to implement this standard. Please address the information to the to implement this standard. Please address the information to the
IETF at ietf-ipr@ietf.org. IETF at ietf-ipr@ietf.org.
11.1 IPR Disclosure Acknowledgement 11.1 IPR Disclosure Acknowledgement
By submitting this Internet-Draft, I certify that any applicable By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been disclosed, patent or other IPR claims of which I am aware have been disclosed,
and any of which I become aware will be disclosed, in accordance with and any of which I become aware will be disclosed, in accordance
RFC 3668. with RFC 3668.
12. Full Copyright Statement 12. Full Copyright Statement
Copyright (C) The Internet Society (2004). This document is Copyright (C) The Internet Society (2004). This document is
subject to the rights, licenses and restrictions contained in BCP subject to the rights, licenses and restrictions contained in BCP
78, and except as set forth therein, the authors retain all their 78, and except as set forth therein, the authors retain all their
rights. rights.
This document and the information contained herein are provided This document and the information contained herein are provided
on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
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