draft-ietf-mpls-p2mp-requirement-01.txt   draft-ietf-mpls-p2mp-requirement-02.txt 
Network Working Group Seisho Yasukawa (NTT) Network Working Group Seisho Yasukawa (NTT)
Internet Draft Editor Internet Draft Editor
Category: Standards Track
Expiration Date: June 2004 January 2004 Expiration Date: August 2004 March 2004
Requirements for Point to Multipoint extension to RSVP-TE Requirements for Point to Multipoint extension to RSVP-TE
<draft-ietf-mpls-p2mp-requirement-01.txt> <draft-ietf-mpls-p2mp-requirement-02.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
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Drafts. Drafts.
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Abstract Abstract
This document presents a set of requirements for Point-to-Multipoint This document presents a basic set of requirements for Point-to-
(P2MP) Traffic Engineering (TE) extensions to Multiprotocol Label Multipoint(P2MP) Traffic Engineering (TE) extensions to Multiprotocol
Switching (MPLS). It specifies functional requirements for RSVP-TE in Label Switching (MPLS). It specifies functional requirements for
order to deliver P2MP applications over a MPLS TE infrastructure. It RSVP-TE in order to deliver P2MP applications over a MPLS TE
is intended that potential solutions, that specify RSVP-TE procedures infrastructure. It is intended that solutions that specify RSVP-TE
for P2MP TE LSP setup, use these requirements as a guideline. It is procedures for P2MP TE LSP setup satisfy these requirements. There is
not intended to specify solution specific details in this document. no intent to specify solution specific details in this document.
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 also
encompass the requirements of L2SC, TDM, lambda and port switching encompass the requirements of L2SC, TDM, lambda and port switching
networks managed by Generalized MPLS (GMPLS) protocols. Protocol networks managed by Generalized MPLS (GMPLS) protocols. Protocol
solutions developed to meet the requirements set out in this document solutions developed to meet the requirements set out in this document
must be equally applicable to MPLS and GMPLS. must be equally applicable to MPLS and GMPLS.
Table of Contents Table of Contents
1. Introduction .................................................. 4 1. Introduction .................................................. 4
2. Definitions ................................................... 5 2. Definitions ................................................... 5
2.1 Acronyms .................................................. 5 2.1 Acronyms .................................................. 5
2.2 Terminology ............................................... 5 2.2 Terminology ............................................... 5
2.3 Conventions ............................................... 6 2.3 Conventions ............................................... 7
3. Problem statements ............................................ 7 3. Problem statements ............................................ 7
3.1 Motivation ................................................ 7 3.1 Motivation ................................................ 7
3.2 Requirements overview ..................................... 7 3.2 Requirements overview ..................................... 8
4. Application Specific Requirements ............................. 9 4. Application Specific Requirements .............................10
4.1 P2MP tunnel for IP multicast data ......................... 9 4.1 P2MP tunnel for IP multicast data .........................10
4.2 P2MP TE backbone network for IP multicast network .........10 4.2 P2MP TE backbone network for IP multicast network .........11
4.3 Layer 2 Multicast Over MPLS ...............................11 4.3 Layer 2 Multicast Over MPLS ...............................12
4.4 VPN multicast network .....................................12 4.4 VPN multicast network .....................................13
4.5 GMPLS network .............................................13 4.5 GMPLS network .............................................14
5. Detailed requirements for P2MP TE extensions ..................13 5. Detailed requirements for P2MP TE extensions ..................14
5.1 P2MP LSP tunnels ..........................................13 5.1 P2MP LSP tunnels ..........................................14
5.2 P2MP explicit routing .....................................14 5.2 P2MP explicit routing .....................................15
5.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes .15 5.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes .16
5.4 P2MP TE LSP establishment, teardown, and modification 5.4 P2MP TE LSP establishment, teardown, and modification
mechanisms ................................................16 mechanisms ................................................17
5.5 Failure Reporting and Error Recovery ......................16 5.5 Failure Reporting and Error Recovery ......................17
5.6 Record route of P2MP TE LSP tunnels .......................17 5.6 Record route of P2MP TE LSP tunnels .......................18
5.7 Call Admission Control (CAC) and QoS control mechanism 5.7 Call Admission Control (CAC) and QoS control mechanism
of P2MP TE LSP tunnels ....................................18 of P2MP TE LSP tunnels ....................................18
5.8 Reoptimization of P2MP TE LSP .............................18 5.8 Reoptimization of P2MP TE LSP .............................19
5.9 IPv4/IPv6 support .........................................19 5.9 IPv4/IPv6 support .........................................19
5.10 P2MP MPLS Label ..........................................19 5.10 P2MP MPLS Label ..........................................20
5.11 Routing advertisement of P2MP capability .................19 5.11 Routing advertisement of P2MP capability .................20
5.12 Multi-Area/AS LSP ........................................19 5.12 Multi-Area/AS LSP ........................................20
5.13 P2MP MPLS management .....................................20 5.13 P2MP MPLS OAM ............................................20
5.14 Scalability ..............................................20 5.14 Scalability ..............................................21
5.15 Backwards Compatibility ..................................20 5.15 Backwards Compatibility ..................................21
5.16 GMPLS ....................................................21 5.16 GMPLS ....................................................22
5.17 Requirements for Hierarchical P2MP TE LSPs ...............21 5.17 Requirements for Hierarchical P2MP TE LSPs ...............22
5.18 P2MP Crankback routing ...................................22 5.18 P2MP Crankback routing ...................................23
6. Security Considerations........................................22 6. Security Considerations........................................23
7. Acknowledgements ..............................................22 7. Acknowledgements ..............................................23
8. References ....................................................22 8. References ....................................................23
8.1 Normative References ......................................22 8.1 Normative References ......................................23
8.2 Informational References ..................................23 8.2 Informational References ..................................24
9. Author's Addresses ............................................24 9. Editor's Address ..............................................26
10. Intellectual Property Consideration ...........................26 10. Authors' Addresses ............................................26
11. Full Copyright Statement ......................................26 11. Intellectual Property Consideration ...........................27
11.1 IPR Disclosure Acknowledgement ...........................28
12. Full Copyright Statement ......................................28
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 is
limited to P2P applications. There are P2MP applications like Content limited to P2P applications. There are P2MP applications like Content
Distribution, Interactive Multimedia and VPN multicast that would Distribution, Interactive Multimedia and VPN multicast that would
also benefit from these TE capabilities. This clearly motivates for also benefit from these TE capabilities. This clearly motivates
enhancement of base MPLS-TE tool box in order to support P2MP enhancements of the base MPLS-TE tool box in order to support P2MP
applications. applications.
This document presents a set of requirements for Point-to-Multipoint This document presents a set of requirements for Point-to-Multipoint
(P2MP) Traffic Engineering (TE) extensions to Multiprotocol Label (P2MP) Traffic Engineering (TE) extensions to Multiprotocol Label
Switching (MPLS). It specifies functional requirements for RSVP-TE Switching (MPLS). It specifies functional requirements for RSVP-TE
[RFC3209] in order to deliver P2MP applications over a MPLS TE. [RFC3209] in order to deliver P2MP applications over a MPLS TE.
It is intended that potential solutions, that specify RSVP-TE It is intended that solutions, that specify RSVP-TE
procedures for P2MP TE LSP setup, use these requirements as a procedures and extensions for P2MP TE LSP setup, satisfy these
guideline. It is not intended to specify solution specific details requirements. It is not intended to specify solution specific details
in this document. in this document.
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 also
encompass the requirements of TDM, lambda and port switching networks encompass the requirements of TDM, lambda and port switching networks
managed by Generalized MPLS (GMPLS) protocols. Protocol solutions managed by Generalized MPLS (GMPLS) protocols. Protocol solutions
developed to meet the requirements set out in this document must be developed to meet the requirements set out in this document must be
equally applicable to MPLS and GMPLS. equally applicable to MPLS and GMPLS.
Content Distribution (CD), Interactive multi-media (IMM), and VPN Content Distribution (CD), Interactive multi-media (IMM), and VPN
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bandwidth resources, memory and MPLS (e.g. label) resources in the bandwidth resources, memory and MPLS (e.g. label) resources in the
network. 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 in a large-scale environment, P2MP TE mechanisms are required
specifically to support P2MP TE LSPs. Existing MPLS TE mechanisms specifically to support P2MP TE LSPs. Existing MPLS TE mechanisms
[RFC3209] do not support P2MP TE LSPs so new mechanisms must be [RFC3209] do not support P2MP TE LSPs so new mechanisms must be
developed. developed.
This should be achieved without running a multicast routing protocol This should be achieved without running a multicast routing protocol
in the network core and with maximum re-use of the existing MPLS in the network core, and with maximum re-use of the existing MPLS
protocols in particular MPLS Traffic Engineering. protocols: in particular, MPLS Traffic Engineering.
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 replication at various branching points in the efficient packet or data replication at various branching points in
network. RSVP-TE will be used for setting up a P2MP TE LSP with the network. RSVP-TE will be used for setting up a P2MP TE LSP with
enhancements to existing P2P TE LSP procedures. The P2MP TE LSP setup enhancements to existing P2P TE LSP procedures. The P2MP TE LSP setup
mechanism will include the ability to add/remove receivers to/from an mechanism will include the ability to add/remove receivers to/from an
existing P2MP TE LSP. existing P2MP TE LSP.
Moreover, multicast traffic cannot currently benefit from P2P TE LSP. Moreover, multicast traffic cannot currently benefit from P2P TE
Hence, CAC for P2P TE LSP cannot take into account the bandwidth used LSPs. Hence, CAC for P2P TE LSP cannot take into account the
for multicast traffic. P2MP TE will allow to count the bandwidth used bandwidth used for multicast traffic. P2MP TE will allow the
by unicast and multicast traffic by means of CAC. bandwidth used by unicast and multicast traffic to be counted by
means of CAC.
The problem statement is discussed in the following section. This The problem statement is discussed in Section 3. This
document discusses various applications that can use P2MP TE LSP. document discusses various applications that can use P2MP TE LSP.
Detailed requirements for the setup of a P2MP MPLS TE LSP using Detailed requirements for the setup of a P2MP MPLS TE LSP using
RSVP-TE are described. Application specific requirements are also RSVP-TE are described. Application specific requirements are also
described. described.
2. Definitions 2. Definitions
2.1 Acronyms 2.1 Acronyms
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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 more than one
egress LSR (also referred to as the leaf). egress LSR (also referred to as the leaf).
P2MP path: 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 P2MP TE LSP from its ingress LSR to all of its egress LSRs. a P2MP TE LSP from its ingress LSR to all of its egress LSRs.
This path may be viewed as a tree. sub-P2MP tree:
sub-P2MP path:
A sub-P2MP path is a portion of a P2MP path 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 path 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 path. ALL downstream LSRs that are also members of the P2MP tree.
A sub-P2MP path may be viewed as a sub-tree.
P2P sub-LSP path: 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 messages
that set up the P2MP TE LSP. that set up the P2MP TE LSP.
egress LSR: egress LSR:
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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 path and is in An LSR that is already a member of the P2MP tree and is in
process of signaling a new sub-P2MP path. process of signaling a new sub-P2MP tree.
prune LSR: prune LSR:
An LSR that is already a member of the P2MP path and is in An LSR that is already a member of the P2MP tree and is in
process of tearing down an existing sub-P2MP path. process of tearing down an existing sub-P2MP tree.
P2MP-ID (Pid):
The ID that can be used to map a set of P2P sub- LSPs to a
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 this
document are to be interpreted as described in RFC2119 [5]. 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
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characteristics. It also wastes bandwidth resources, memory and MPLS characteristics. It also wastes bandwidth resources, memory and MPLS
(e.g. label) resources in the network. (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 in a large scale environment, P2MP TE mechanisms are
required. Existing MPLS P2P TE mechanisms have to be enhanced to required. Existing MPLS P2P TE mechanisms have to be enhanced to
support P2MP TE LSP. support P2MP TE LSP.
3.2. Requirements Overview 3.2. Requirements Overview
This document is proposing 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. This should be achieved without running a multicast routing
protocol in the network core and with maximum re-use of the existing protocol in the network core and with maximum re-use of the existing
MPLS protocols. Note that the use of MPLS forwarding to carry the MPLS protocols. Note that the use of MPLS forwarding to carry the
multicast traffic may also be useful in the context of some network multicast traffic may also be useful in the context of some network
design where it is being desired to avoid running some multicast design where it is being desired to avoid running some multicast
routing protocol like PIM [PIM-SM] or BGP (which might be required routing protocol like PIM [PIM-SM] or BGP (which might be required
for the use of PIM). for the use of PIM).
A P2MP LSP will be set up with TE constraints and will allow A P2MP LSP will be set up with TE constraints and will allow
efficient MPLS packet replication at various branching points in the efficient MPLS packet replication at various branching points in the
network. RSVP-TE will be used for setting up a P2MP TE LSP with network. RSVP-TE will be used for setting up a P2MP TE LSP with
enhancements to existing P2P TE LSP procedures. enhancements to existing P2P TE LSP procedures.
The P2MP TE LSP setup mechanism will include the ability to The P2MP TE LSP setup mechanism will include the ability to
add/remove egress LSRs to/from an existing P2MP TE LSP and should add/remove egress LSRs to/from an existing P2MP TE LSP and should
support all the TE LSP management procedures defined for P2P TE LSP support all the TE LSP management procedures defined for P2P TE LSP
(like the non disruptive rerouting - the so called "Make before (like the non disruptive rerouting - the so called "Make before
break" procedure). break" procedure).
The computation of P2MP TE paths 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.
The MPLS WG will specify how to build P2MP TE LSPs. The usage of A separate document(s) will specify how to build P2MP TE LSPs. The
those solutions will be application dependent and is out of the scope usage of those solutions will be application dependent and is out of
of this draft. However, it is a requirement that those solutions be the scope of this document. However, it is a requirement that those
applicable to GMPLS as well as MPLS so that only a single set of solutions be applicable to GMPLS as well as to MPLS so that only a
solutions are developed. 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
The figure above shows a single ingress (I-LSR1), and four egresses Figure 1 shows a single ingress (I-LSR1), and four egresses
(E-LSR2, E-LSR3, E-LSR4 and E-LSR5). I-LSR1 is attached to a traffic (E-LSR2, E-LSR3, E-LSR4 and E-LSR5). I-LSR1 is attached to a traffic
source that is generating traffic for a P2MP application. source 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 that we wish to achieve: The following are the objectives of P2MP LSP establishment and use.
a) A P2MP TE LSP path which satisfies various a) A P2MP TE LSP tree which satisfies various constraints is pre-
constrains is pre-determined and supplied to ingress I-LSR1. determined and supplied to ingress I-LSR1.
Note that no assumption is made on whether the path 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.
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. There should not be any
restriction on the possibility to support the set of restriction on the possibility to support the set of
constraints already defined for point to point TE LSPs. constraints already defined for point to point TE LSPs. A new
constraint may specify which LSRs should be used as branch
points for the P2MP LSR in order to take 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 by means of RSVP-TE from I-LSR1 to
E-LSR2, E-LSR3 and E-LSR4 using the path information. E-LSR2, E-LSR3 and 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 packets
and send them to E-LSR3 and E-LSR4. 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 path is determined and a sub-P2MP path from traffic, a new tree is determined and a sub-P2MP tree from
LSR2 to E-LSR5 is grafted onto the P2MP path. LSR2 becomes LSR2 to E-LSR5 is grafted onto the P2MP tree. LSR2 becomes
a branch LSR. a branch LSR.
4. Application Specific Requirements 4. Application Specific Requirements
This section describes some of the applications that P2MP MPLS This section describes some of the applications that P2MP MPLS
TE is applicable to along with application specific requirements. TE is applicable to along with application specific requirements.
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 features and functions that any P2MP solution must provide in the features and functions that any P2MP solution must provide in
order to be of wide use and applicability. This section is not meant order to be of wide use and applicability. This section is not meant
to be exhaustive and not limited to the described applications. to be exhaustive, and P2MP is not limited to the described
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 multicast source and several egress LSRs which support several IP multicast source and several egress LSRs which support several
IP multicast receivers. Instead of using an IP multicast routing IP multicast receivers. Instead of using an IP multicast routing
protocol in the network core, a P2MP TE LSP is established over protocol in the network core, a P2MP TE LSP is established over
the network and IP multicast data are tunneled from an ingress LSR the network and IP multicast data are tunneled from an ingress LSR
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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 are utilized to construct a provider
network which can deliver VPN multicast service(s) to its customers. 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
[BGP/MPLS IP VPNs], 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. It is
desirable that P2MP MPLS TE can be used for Layer3 VPN data desirable that P2MP MPLS TE can be used for Layer3 VPN data
transmission. transmission.
Another example is a Layer2 VPN that supports multipoint Another example is a Layer2 VPN that supports multipoint
LAN connectivity service. In an Ethernet network environment, IP LAN 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).
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to use P2MP features. Therefore, it is a requirement that all the to use P2MP features. Therefore, it is a requirement that all the
features/mechanisms (and protocol extensions) that will be defined to features/mechanisms (and protocol extensions) that will be defined to
provide MPLS P2MP TE LSPs will be equally applicable to P2MP PSC and provide MPLS P2MP TE LSPs will be equally applicable to P2MP PSC and
non-PSC TE-LSPs. non-PSC TE-LSPs.
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 RSVP-TE extensions MUST be applicable to signaling 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 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
path. tree.
In order to scale to a large number of branches, P2MP TE LSPs should In order to scale to a large number of branches, P2MP TE LSPs SHOULD
be identified by unique identifier that is constant for the whole LSP be identified by a unique identifier (the P2MP ID or Pid) that is
regardless of the number of branches and/or leaves. Therefore, the constant for the whole LSP regardless of the number of branches
identification of the P2MP session by its destination addresses is and/or leaves. Therefore, the identification of the P2MP session by
not adequate. its destination addresses is not adequate.
5.2 P2MP explicit routing 5.2 P2MP explicit routing
Various optimizations in P2MP path formation need to be applied to Various optimizations in P2MP tree formation need to be applied to
meet various QoS requirements and operational constraints. meet various QoS requirements and operational constraints.
Some P2MP applications may request a bandwidth guaranteed P2MP path
Some P2MP applications may request a bandwidth guaranteed P2MP tree
which satisfies end-to-end delay requirements. And some operators which satisfies end-to-end delay requirements. And some operators
may want to set up a cost minimum P2MP path by specifying branch LSRs may want to set up a cost minimum P2MP tree by specifying branch LSRs
explicitly. explicitly.
The P2MP TE solution therefore MUST provide a means of establishing The P2MP TE solution therefore MUST provide a means of establishing
arbitrary P2MP paths under the control of an external path arbitrary P2MP trees under the control of an external tree
computation process or path configuration process or dynamic path computation process or path configuration process or dynamic tree
computation process located on the ingress LSR. Figure 4 shows two computation process located on the ingress LSR. Figure 4 shows two
typical examples. typical examples.
A A A A
| / \ | / \
B B C B B C
| / \ / \ | / \ / \
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 path SPF P2MP path 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 Steiner[STEINER] P2MP path (Cost minimum P2MP path). One example is the Steiner P2MP tree (Cost minimum P2MP tree)
This P2MP path is suitable for constructing cost minimum P2MP path. [STEINER]. This P2MP tree is suitable for constructing a cost minimum
To realize this P2MP path, several intermediate LSRs must be both P2MP tree. To realize this P2MP tree, several intermediate LSRs must
MPLS data terminating LSR and transit LSR (LSR E, F, G, H, I, J, K, be both MPLS data terminating LSRs and transit LSRs (LSRs E, F, G, H,
in the figure 4). This means that the LSR must perform both label I, J and K in the figure 4). This means that the LSRs must perform
swapping and popping at the same time. Therefore, the P2MP TE both label swapping and popping at the same time. Therefore, the P2MP
solution MUST support a mechanism that can setup this kind of TE solution MUST support a mechanism that can setup this kind of
bud LSR between an ingress LSR and egress LSRs. bud LSR between an ingress LSR and egress LSRs.
Another example is CSPF (Constraint Shortest Path Fast) P2MP path. By Another example is a CSPF (Constraint Shortest Path Fast) P2MP tree.
some metric (which can be set upon any specific criteria like the By some metric (which can be set upon any specific criteria like the
delay, bandwidth, a combination of those), one can calculate a cost delay, bandwidth, a combination of those), one can calculate a cost
minimum P2MP path. This P2MP path is suitable for carrying real time minimum P2MP tree. This P2MP tree is suitable for carrying real time
traffic. traffic.
To support explicit setup of any reasonable P2MP path 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 path 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 of TE LSP. Being implementation specific (more precisely dependent on
the data structure specific representation and its processing), the the data structure specific representation and its processing), the
detailed method for controlling the P2MP TE LSP topology depends on detailed method for controlling the P2MP TE LSP topology depends on
how the control plane represents the P2MP TE LSP data plane entity. how the control plane represents the P2MP TE LSP data plane entity.
For instance, a P2MP TE LSP can be simply represented as a 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 also, effectiveness of the potential solutions is left outside Here the effectiveness of the potential solutions is left outside
the scope of this document. In any case, it is expected that this the scope of this document. In any case, it is expected that this
control must be driven by the ingress LSR. 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 path is completely specified if all of the required A P2MP tree is completely specified if all of the required
branches and hops between a sender and leaf LSR are indicated. branches and hops between a sender and leaf LSR are indicated.
A P2MP path 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 hops in the explicit path, or using widely scoped abstract loose hops in the explicit path, or using widely scoped abstract
nodes such as IPv4 prefixes shorter than 32 bits or AS numbers. nodes such as IPv4 prefixes shorter than 32 bits, or AS numbers.
A partially specified P2MP path may be particularly useful in A partially specified P2MP tree may be particularly useful in
inter-area and inter-AS situations. inter-area and inter-AS situations.
Protocol solutions SHOULD include a way to specify loose Protocol solutions SHOULD include a way to specify loose
hops and widely scoped abstract nodes in the explicit source- hops and widely scoped abstract nodes in the explicit source-
based control of the P2MP path as defined in the previous based control of the P2MP tree as defined in the previous
section. Where this support is provided, protocol solutions section. Where this support is provided, protocol solutions
MUST allow downstream LSRs to apply further explicit MUST allow downstream LSRs to apply further explicit
control to the P2MP path to resolve a partially specified path control to the P2MP tree to resolve a partially specified tree
into a (more) completely specified path. into a (more) completely specified tree.
Protocol solutions MUST allow the P2MP path 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 allow
the full path to be computed. 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 path being computed by some downstream LSRs (e.g. case of In case of a tree being computed by some downstream LSRs (e.g. the
hops specified as loose hops), the solution SHOULD provide the case of hops specified as loose hops), the solution MUST provide the
ability for the ingress LSR of the P2MP TE LSP to learn the full ability for the ingress LSR of the P2MP TE LSP to learn the full
P2MP path. Note that this requirement may be relaxed in some P2MP tree. Note that this requirement MAY be relaxed in some
environment (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 large scale P2MP TE LSPs
establishment and teardown in a scalable manner. establishment and teardown in a scalable manner.
In addition to P2MP TE LSP establishment and teardown mechanism, In addition to P2MP TE LSP establishment and teardown mechanism,
it SHOULD implement partial P2MP path modification mechanism. it SHOULD implement partial P2MP tree modification mechanism.
For the purpose of adding sub-P2MP TE LSPs for existing P2MP TE LSP, For the purpose of adding sub-P2MP TE LSPs to an existing P2MP TE
the extension SHOULD support grafting mechanism. For the purpose of LSP, the extensions SHOULD support a grafting mechanism. For the
deleting a sub-P2MP TE LSPs from existing P2MP TE LSP, the extension purpose of deleting a sub-P2MP TE LSPs from an existing P2MP TE
SHOULD support pruning mechanism. LSP, 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 the
grafting and pruning node and its downstream nodes. Moreover, both grafting and pruning node and its downstream nodes. Moreover, both
grafting and pruning operations MUST not be traffic disruptive for grafting and pruning operations MUST not be traffic disruptive for
the traffic currently forwarded along the P2MP path. the traffic currently forwarded along the P2MP tree.
5.5 Failure Reporting and Error Recovery 5.5 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 upstream
as for a P2P LSP. 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 to recover any impacted sub-P2MP TE LSPs. and restoration allowing recovery of any impacted sub-P2MP TE LSPs.
In particular, it is required to provide fast protection mechanisms In particular, a solution MUST provide fast protection mechanisms
applicable to P2MP TE LSP similar to the solutions specified in [FRR] applicable to P2MP TE LSP similar to the solutions specified in [FRR]
for P2P TE LSPs. Note also that no assumption is made on whether for P2P TE LSPs. Note also that no assumption is made on whether
backup paths for P2MP TE LSPs should or not be shared with P2P TE backup paths for P2MP TE LSPs should or should not be shared with P2P
LSPs backup paths. TE LSPs backup paths.
A P2MP TE solution MUST support P2MP fast protection mechanism A P2MP TE solution MUST support P2MP fast protection mechanism
to handle P2MP applications sensitive to traffic disruption. to handle P2MP applications sensitive to traffic disruption.
The report of the failure of delivery to fewer than all of the egress 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. nodes SHOULD NOT cause automatic teardown of the P2MP TE LSP.
That is, while some egress nodes remain connected to the P2MP path it 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 should be a matter of local policy at the ingress whether the P2MP
LSP is retained. LSP is retained.
When all egress node downstreams of a branch node have become When all egress nodes downstreams of a branch node have become
disconnected from the P2MP path, 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 through recovery or protection
mechanisms, the branch node MAY remove itself from the P2MP path. mechanisms, the branch node MAY remove itself from the P2MP tree.
Since the faults that severed the various downstream egress nodes Since the faults that severed the various downstream egress nodes
from the P2MP path may be disparate, the branch node MUST report all from the P2MP tree may be disparate, the branch node MUST report all
such errors to its upstream neighbor. The ingress node can then such errors to its upstream neighbor. The ingress node can then
decide to re-compute the path to that particular egress node, around decide to re-compute the path to those particular egress nodes,
the failure point. 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 paths to restore them after branch nodes to recompute sub-P2MP trees to restore them after
failures. In the event of successful repair, no error notification is failures. In the event of successful repair, error notifications
reported to upstream nodes, but the new paths are reported if route SHOULD NOT be reported to upstream nodes, but the new paths are
recording is in use. Crankback requirements are discussed in reported if route recording is in use. Crankback requirements are
[CRANKBACK]. discussed in Section 5.18.
5.6 Record route of P2MP TE LSP tunnels 5.6 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 purpose:Management, operation of some very important for various purposes such as management and operation
local recovery mechanism like Fast Reroute [FRR]. A network operator of some local recovery mechanisms like Fast Reroute [FRR]. A network
uses this information to manage P2MP TE LSP. Therefore, topology operator uses this information to manage P2MP TE LSPs. Therefore,
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, conventional Record Route mechanism is useful. For this purpose, the conventional Record Route mechanism is useful.
As with other conventional mechanism, this information should be As with other conventional mechanism, this information should be
forwarded upstream towards the sender node. The P2MP TE solution MUST forwarded upstream towards the sender node. The P2MP TE solution MUST
support a mechanism which can collect and update P2MP path topology support a mechanism which can collect and update P2MP tree topology
information after P2MP LSP establishment and modification process. information after P2MP LSP establishment and modification process.
It is RECOMMENDED that those information are collected in a data It is RECOMMENDED that the information is collected in a data
format by which the sender node can recognize the P2MP path topology format 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
or node-id [NODE-ID]. and node-id [NODE-ID].
5.7 Call Admission Control (CAC) and QoS Control mechanism 5.7 Call Admission Control (CAC) and QoS Control mechanism
of P2MP TE LSP tunnels of P2MP TE LSP tunnels
P2MP TE LSP share network resource with P2P TE LSP. Therefore it is P2MP TE LSPs may share network resource with P2P TE LSPs. Therefore
important to use CAC and QoS as P2P TE LSP for easy and scalable it is important to use CAC and QoS in the same way as P2P TE LSPs
operation. for easy and scalable operation.
In particular, it should be highlighted that because In particular, it should be highlighted that because Multicast
Multicast traffic cannot make use of point to point TE LSP, multicast traffic cannot make use of P2P TE LSP, multicast traffic cannot be
traffic cannot be easily taken into account by point to point in easily taken into account by P2P TE LSPs when performing CAC.
order to perform CAC. The use of P2MP TE LSP will now allow for an The use of P2MP TE LSP will now allow for an accounting of the
accounting of the unicast and multicast traffic for bandwidth unicast and multicast traffic for bandwidth reservation.
reservation.
P2MP TE solution MUST both supports FF and SE reservation style. P2MP TE solutions MUST support both FF and SE reservation styles.
P2MP TE solution MUST be applicable to Diffserv-enabled network 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.
This solution SHOULD also satisfy DS-TE requirement [RFC3564] and Any solution SHOULD also satisfy the DS-TE requirements [RFC3564] and
interoperable smoothly with current P2P DS-TE protocol specification. 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 LSP 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. shared with P2P TE LSP or be dedicated for P2MP use.
5.8 Reoptimization of P2MP TE LSP 5.8 Reoptimization of P2MP TE LSP
The detection of a more optimal path is an example of situation where The detection of a more optimal path is an example of a situation
P2MP TE LSP re-routing is may be required. While re-routing is in where P2MP TE LSP re-routing may be required. While re-routing is in
progress, an important requirement is avoiding double bandwidth progress, an important requirement is avoiding double bandwidth
reservation (over the common parts between the old and new LSP) reservation (over the common parts between the old and new LSP)
thorough the use of resource sharing. Make-before-break thorough the use of resource sharing. Make-before-break
(see [RFC3209]) delivers simultaneously a solution to these (see [RFC3209]) delivers simultaneously a solution to these
requirements. 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 rerouted. there is no traffic disruption when the P2MP TE LSP is re-routed.
There is a possibility to achieve make-before-break that only It is possibile to achieve make-before-break that only
applies to a sub-P2MP path without impacting the data on the all of applies to a sub-P2MP tree without impacting the data on all of
the other parts of the P2MP path. the other parts 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 sub-tree with no impact on the rest of the tree (no label a sub-tree with no impact on the rest of the tree (no label
reallocation, no change in identifiers...). reallocation, no change in identifiers, etc.).
The solution SHOULD also provide the ability for the ingress LSR
to 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. (e.g. the branch node setup a new sub-tree, then splices 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 5.9 IPv4/IPv6 support
A P2MP TE solution MUST be applicable to IPv4/IPv6. Any P2MP TE solution MUST be equally applicable to IPv4 and IPv6.
5.10 P2MP MPLS Label 5.10 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 TE LSP and MUST NOT impede the operation of P2P TE LSPs within P2MP TE LSPs and MUST NOT impede the operation of P2P TE LSPs within
the same network. A P2MP TE solution MUST be specified in such the same network. A P2MP TE solution MUST be specified in such
a way that it allows P2MP and P2P TE LSPs to be signaled on the a way that it allows P2MP and P2P TE LSPs to be signaled on the
same interface. Labels for P2MP TE LSPs and P2P TE LSPs MAY be same interface. Labels for P2MP TE LSPs and P2P TE LSPs MAY be
assigned from shared or dedicated label space(s). Label space assigned from shared or dedicated label space(s). Label space
shareability is implementation specific. shareability is implementation specific.
5.11 Routing advertisement of P2MP capability 5.11 Routing advertisement of P2MP capability
This document has identified several high-level requirements for Several high-level requirements have been identified to determine
enhancements to routing and signalling protocols to support the capabilities of LSRs within a P2MP network. This information is
P2MP MPLS. These are needed to facilitate the computation of P2MP to facilitate the computation of P2MP trees using TE constraints
paths using TE constraints so that explicit source-control may be within a network that contains LSRs that do not all have the same
applied to the LSP paths as they are signaled through the network. capabilities levels with respect to P2MP signaling and data
forwarding.
These requirements include but not restricted 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 applicability of these requirements is for further study. It is expected that it may be appropriate to gather this information
These requirements are developed in a separate document. through extensions to TE IGPs (see [RFC3630] and [IS-IS-TE]), but the
precise requirements and mechanisms are out of the scope of this
document. It is expected that a separate document will cover this
requirement.
5.12 Multi-Area/AS LSP 5.12 Multi-Area/AS LSP
P2MP TE solution SHOULD support multi-Area/AS LSP. P2MP TE solutions SHOULD support multi-area/AS P2MP LSPs.
A separate document may deal with the specifics of inter-area The precise requirements in support of multi-area/AS P2MP LSPs
and inter-AS P2MP TE LSPs. is out of the scope of this document. It is expected that a separate
document will cover this requirement.
5.13 P2MP MPLS management 5.13 P2MP MPLS OAM
The MPLS MIB should be enhanced to provide P2MP TE LSP management. Management of P2MP LSPs is as important as the management of P2P
P2MP TE LSPs MUST have a unique identifier whose definition MAY be LSPs.
partially or entirely shared with P2P TE LSP identifiers used for
management purposes. The MPLS and GMPLS MIB modules MUST be enhanced to provide P2MP TE
LSP management.
In order to facilitate correct management, P2MP TE LSPs MUST have
unique identifiers.
OAM facilities will have special demands in P2MP environments
especially within the context of tracing the paths and connectivity
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
document will cover these requirements.
5.14 Scalability 5.14 Scalability
Scalability is a key requirement in P2MP MPLS systems. Solutions Scalability is a key requirement in P2MP MPLS systems. Solutions
should 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 of the following: the number of recipients, the number of branch any of the following:
points and the number of branches. Both scalability of performance - the number of recipients
and operation must be considered. - the number of branch points
- the number of branches.
Both scalability of performance and operation MUST be considered.
Key considerations may include: Key considerations SHOULD include:
- the amount of refresh processing associated with maintaining a - the amount of refresh processing associated with maintaining a
P2MP TE LSP. P2MP TE LSP.
- the amount of protocol state that must be maintained by transit - the amount of protocol state that must be maintained by ingress
LSRs along a P2MP path. 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 P2MP LSP as a function of the number of egress LSRs. a 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 a P2MP
TE LSP (i.e. the message size). 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 5.15 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 would be to offer P2MP services
across legacy MPLS networks without any change to any LSR in the across legacy MPLS networks without any change to any LSR in the
network. 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 of all protocol solutions that any LSR
that implements the solution shall not be prohibited by that act from that 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 5.16 GMPLS
Solutions for MPLS P2MP TE-LSPs when applied to GMPLS P2MP PSC Solutions for MPLS P2MP TE-LSPs when applied to GMPLS P2MP PSC
or non-PSC TE-LSPs must be backward and forward compatible with or non-PSC TE-LSPs MUST be backward and forward compatible with
the other features of GMPLS including: the other features of GMPLS including:
o control and data plane separation (IF_ID RSVP_HOP and - control and data plane separation (IF_ID RSVP_HOP and
IF_ID ERROR_SPEC), IF_ID ERROR_SPEC),
o full support of numbered and unnumbered TE links (see [RFC 3477] - full support of numbered and unnumbered TE links (see [RFC 3477]
and [GMPLS-ROUTING]), and [GMPLS-ROUTE]),
o use of the GENERALIZED_LABEL_REQUEST and the GENERALIZED_LABEL - use of the GENERALIZED_LABEL_REQUEST and the GENERALIZED_LABEL
(C-Type 2 and 3) in conjunction with the LABEL_SET and the (C-Type 2 and 3) in conjunction with the LABEL_SET and the
ACCEPTABLE_LABEL_SET object, ACCEPTABLE_LABEL_SET object,
o processing of the ADMIN_STATUS object, - processing of the ADMIN_STATUS object,
o processing of the PROTECTION object, - processing of the PROTECTION object,
o support of Explicit Label Control, - support of Explicit Label Control,
o processing of the Path_State_Removed Flag, - processing of the Path_State_Removed Flag,
o handling of Graceful Deletion procedures. - handling of Graceful Deletion 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 (i.e.
constraints that are applicable independently of the LSP class) constraints that are applicable independently of the LSP class)
should be allowed during P2MP TE LSP message processing. It has to SHOULD be allowed during P2MP TE LSP message processing. It has to
be emphasized that path computation and management techniques shall be emphasized that path computation and management techniques shall
be as close as possible than those being used for PSC P2P TE LSPs be as close as possible to those being used for PSC P2P TE LSPs
and P2MP TE LSPs. and P2MP TE LSPs.
Finally, note that bi-directional TE LSPs are not applicable to Finally, note that bi-directional TE LSPs are not applicable to
multicast traffic. Although many leaf nodes may be considered as multicast traffic. Although many leaf nodes may be considered as
senders in a multicast group, a P2MP TE LSP models a single senders in a multicast group, a P2MP TE LSP models a single
distribution tree from a sender to multiple recipients. If such distribution tree from a sender to multiple recipients. If such
a tree were made bi-directional it would be a multipoint-to-point a tree were made bi-directional it would be a multipoint-to-point
tree in the reverse direction. tree in the reverse direction.
5.17 Requirements for Hierarchical P2MP TE LSPs 5.17 Requirements for Hierarchical P2MP TE LSPs
[LSP-HIER] define concepts and procedures for P2P LSP hierarchy. They [LSP-HIER] defines concepts and procedures for P2P LSP hierarchy.
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 scope of this document. It is expected that a separate document
will cover these requirements.
5.18 P2MP Crankback routing 5.18 P2MP Crankback routing
P2MP solution SHOULD support cranckback requirements as defined in P2MP solutions SHOULD support cranckback requirements as defined in
[CRANKBACK]. In particular, it SHOULD provide sufficient information [CRANKBACK]. In particular, they SHOULD provide sufficient
to a branch LSR from downstream LSRs to allow the branch LSR to information to a branch LSR from downstream LSRs to allow the branch
re-route a sub-tree around any failures or problems in the network. LSR to re-route a sub-tree around any failures or problems in the
network.
6. Security Considerations 6. Security Considerations
This requirements draft does not define any protocol extensions and This requirements document does not define any protocol extensions
does not, therefore, make any changes to any security models. and does not, therefore, make any changes to any security models.
It should be noted that P2MP signaling mechanisms built on P2P It should be noted that P2MP signaling mechanisms built on P2P
signaling are likely to inherit all of the security techniques and RSVP-TE signaling are likely to inherit all of the security
problems associated with RSVP-TE. These problems may be exacerbated techniques and problems associated with RSVP-TE. These problems may
in P2MP situations where security relationships may need to be exacerbated in P2MP situations where security relationships may
maintained between an ingress and multiple egresses. Such issues are need to maintained between an ingress and multiple egresses. Such
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
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 and
Dean Cheng for their review and suggestions on an earlier draft of Dean Cheng for their review and suggestions on an earlier draft of
this document. this document.
8. References 8. References
8.1 Normative References 8.1 Normative References
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
V. and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", Requirement Levels", BCP 14, RFC 2119, March 1997.
RFC 3209, December 2001.
[RFC3031] Rosen, E., Viswanathan, A. and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, January 2001.
[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 Services", RFC and W. Weiss, "An Architecture for Differentiated
2475, December 1998. Services", RFC 2475, December 1998.
[RFC2597] Heinanen, J., Baker, F., Weiss, W. and J. Wroclawski, [RFC2597] Heinanen, J., Baker, F., Weiss, W. and J. Wroclawski,
"Assured Forwarding PHB Group", RFC 2597, June 1999. "Assured Forwarding PHB Group", RFC 2597, June 1999.
[RFC3246] Davie, B., Charny, A., Bennet, J.C.R., Benson, K., Le [RFC2702] D. Awduche, J. Malcolm, J. Agogbua, M. O'Dell, J.
Boudec, J.Y., Davari, S., Courtney, W., Firioiu, V. and D. Stiliadis, McManus, "Requirements for Traffic Engineering Over
"An Expedited Forwarding PHB (Per-Hop Behavior)", RFC 3246, MPLS", RFC2702, September 1999.
March 2002.
[RFC2362] D. Estrin, D. Farinacci, A. Helmy, D. Thaler, S. Deering, [RFC3031] Rosen, E., Viswanathan, A. and R. Callon,
M. Handley, V. Jacobson, C. Liu, P. Sharma, L. Wei, "Protocol "Multiprotocol Label Switching Architecture", RFC 3031,
Independent Multicast-Sparse Mode (PIM-SM): Protocol Specification.", January 2001.
RFC 2362, June 1998.
[RFC2702] D. Awduche, J. Malcolm, J. Agogbua, M. O'Dell, J. McManus, [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan,
"Requirements for Traffic Engineering Over MPLS", RFC2702, V. and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
September 1999. Tunnels", RFC 3209, December 2001.
8.2 Informational References [RFC3246] Davie, B., Charny, A., Bennet, J.C.R., Benson, K., Le
Boudec, J.Y., Davari, S., Courtney, W., Firioiu, V. and
D. Stiliadis, "An Expedited Forwarding PHB (Per-Hop
Behavior)", RFC 3246, March 2002.
[PIM-SM] B. Fenner, M. Hadley, H. Holbrook, I. Kouvelas, "Protocol [RFC3667] Bradner, S., "IETF Rights in Contributions", BCP 78,
Independent Multicast - Sparse Mode (PIM-SM):Protocol Specification RFC 3667, February 2004.
(Revised)", draft-ietf-pim-sm-v2-new-08.txt, October 2003.
[BGP/MPLS IP VPNs] E. Rosen, Y.Rekhter, Editor, "BGP/MPLS IP VPNs", [RFC3668] Bradner, S., Ed., "Intellectual Property Rights in IETF
draft-ietf-l3vpn-rfc2547bis-01.txt, September 2003. Technology", BCP 79, RFC 3668, February 2004.
8.2 Informational References
[RFC3471] Berger, L., Editor, "Generalized Multi-Protocol Label [RFC3471] Berger, L., Editor, "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Functional Description", RFC 3471, Switching (GMPLS) Signaling Functional Description",
January 2003. RFC 3471, January 2003.
[RFC3473] Berger, L., Editor, "Generalized Multi-Protocol Label [RFC3473] Berger, L., Editor, "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling - Resource ReserVation Protocol-Traffic Switching (GMPLS) Signaling - Resource ReserVation
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. Protocol-Traffic Engineering (RSVP-TE) Extensions",
RFC 3473, January 2003.
[RFC3477] K. Kompella, Y. Rekhter, "Signalling Unnumbered Links in [RFC3477] K. Kompella, Y. Rekhter, "Signalling Unnumbered Links
Resource ReSerVation Protocol -Traffic Engineering (RSVP-TE)", in Resource ReSerVation Protocol -Traffic Engineering
RFC3477, January 2003. (RSVP-TE)", RFC3477, January 2003.
[GMPLS-ROUTING] K. Kompella, Y. Rekhter, Editor, "Routing [RFC3564] F. Le Faucheur, W. Lai, "Requirements for Support of
Extensions in Support of Generalized Multi-Protocol Label Switching", Differentiated Services-aware MPLS Traffic
draft-ietf-ccamp-gmpls-routing-08.txt, October 2003. Engineering", RFC 3564, July 2003.
[STEINER] H. Salama, et al., "Evaluation of Multicast Routing [RFC3630] D. Katz, D. Yeung, K. Kompella, "Traffic Engineering
Algorithm for Real-Time Communication on High-Speed Networks," Extensions to OSPF Version 2", RFC 3630, September
IEEE Journal on Selected Area in Communications, pp.332-345, 1997. 2003.
[DJIKSTRA] E. W. Djikstra, "A note on two problem in connection with [PIM-SM] B. Fenner, M. Hadley, H. Holbrook, I. Kouvelas,
graphs," Numerische Mathematik, vol.1, pp.269-271, 1959. "Protocol Independent Multicast - Sparse Mode (PIM-SM):
Protocol Specification (Revised)", draft-ietf-pim-sm-
v2-new-08.txt, October 2003.
[IPMCAST-MPLS] D. Ooms, B. Sales, W. Livens, A. Acharya, F. Griffoul [BGPMPLS-VPN] E. Rosen, Y.Rekhter, Editor, "BGP/MPLS IP VPNs",
and F. Ansari, "Overview of IP Multicast in a Multi-Protocol Label draft-ietf-l3vpn-rfc2547bis-01.txt, September 2003.
Switching (MPLS) Environment", RFC3353, August 2002.
[FRR] P. Pan, D. Gan, G. Swallow, J. P. Vasseur, D. Cooper, [GMPLS-ROUTE] K. Kompella, Y. Rekhter, Editor, "Routing Extensions
A. Atlas, M. Jork,"Fast Reroute Extensions to RSVP-TE for LSP in Support of Generalized Multi-Protocol Label
Tunnels", draft-ietf-mpls-rsvp-lsp-fastreroute-03.txt, July 2003. Switching", draft-ietf-ccamp-gmpls-routing-08.txt,
October 2003.
[RFC3564] F. Le Faucheur, W. Lai, "Requirements for Support of [STEINER] H. Salama, et al., "Evaluation of Multicast Routing
Differentiated Services-aware MPLS Traffic Engineering", RFC3564, Algorithm for Real-Time Communication on High-Speed
July 2003. Networks," IEEE Journal on Selected Area in
Communications, pp.332-345, 1997.
[OSPF-TE] D. Katz, D. Yeung, K. Kompella, "Traffic Engineering [FRR] P. Pan, D. Gan, G. Swallow, J. P. Vasseur, D. Cooper,
Extensions to OSPF Version 2", draft-katz-yeung-ospf-traffic-08.txt, A. Atlas, M. Jork,"Fast Reroute Extensions to RSVP-TE
September 2002. for LSP Tunnels", 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 2002. Engineering", draft-ietf-isis-traffic-04.txt, December
2002.
[CRANKBACK] A. Farrel, A. Satyanarayana, A. Iwata, N. Fujita, G. Ash [CRANKBACK] A. Farrel, A. Satyanarayana, A. Iwata, N. Fujita, G.
S. Marshall, "Crankback Signaling Extensions for MPLS Signaling", Ash, S. Marshall, "Crankback Signaling Extensions for
draft-ietf-ccamp-crankback-00.txt, December 2003. MPLS Signaling", draft-ietf-ccamp-crankback-01.txt,
January 2004.
[LSP-HIER] K. Kompella, Y. Rekhter, "LSP Hierarchy with Generalized [LSP-HIER] K. Kompella, Y. Rekhter, "LSP Hierarchy with
MPLS TE", draft-ietf-mpls-lsp-hierarchy-08.txt, September 2002. Generalized MPLS TE", draft-ietf-mpls-lsp-hierarchy-
08.txt, September 2002.
[NODE-ID] Vasseur, Ali and Sivabalan, "Definition of an RRO node-id [NODE-ID] Vasseur, Ali and Sivabalan, "Definition of an RRO node-
subobject", draft-ietf-mpls-nodeid-subobject-01.txt, June 2003. id subobject", draft-ietf-mpls-nodeid-subobject-01.txt,
June 2003.
9. Author's Addresses 9. Editor's Address
Seisho Yasukawa Seisho Yasukawa
NTT Network Service Systems Laboratories, NTT Corporation NTT Corporation
9-11, Midori-Cho 3-Chome 9-11, Midori-Cho 3-Chome
Musashino-Shi, Tokyo 180-8585 Japan Musashino-Shi, Tokyo 180-8585,
Japan
Phone: +81 422 59 4769 Phone: +81 422 59 4769
Email: yasukawa.seisho@lab.ntt.co.jp Email: yasukawa.seisho@lab.ntt.co.jp
Dimitri Papadimitriou (Alcatel)
10. Authors' Addresses
Dimitri Papadimitriou
Alcatel
Francis Wellensplein 1, Francis Wellensplein 1,
B-2018 Antwerpen, Belgium B-2018 Antwerpen,
Belgium
Phone : +32 3 240 8491 Phone : +32 3 240 8491
Email: dimitri.papadimitriou@alcatel.be Email: dimitri.papadimitriou@alcatel.be
JP Vasseur JP Vasseur
Cisco Systems, Inc. Cisco Systems, Inc.
300 Beaver Brook Road 300 Beaver Brook Road
Boxborough, MA 01719 Boxborough, MA 01719,
USA USA
Email: jpv@cisco.com Email: jpv@cisco.com
Yuji Kamite Yuji Kamite
NTT Communications Corporation NTT Communications Corporation
Tokyo Opera City Tower Tokyo Opera City Tower
3-20-2 Nishi Shinjuku, Shinjuku-ku, Tokyo 3-20-2 Nishi Shinjuku, Shinjuku-ku,
163-1421, Japan Tokyo 163-1421,
Japan
Email: y.kamite@ntt.com Email: y.kamite@ntt.com
Rahul Aggarwal Rahul Aggarwal
Juniper Networks Juniper Networks
1194 North Mathilda Ave. 1194 North Mathilda Ave.
Sunnyvale, CA 94089 Sunnyvale, CA 94089
Email: rahul@juniper.net Email: rahul@juniper.net
Alan Kullberg Alan Kullberg
Motorola Computer Group Motorola Computer Group
120 Turnpike Rd. 120 Turnpike Rd.
Southborough, MA 01772 Southborough, MA 01772
Email: alan.kullberg@motorola.com Email: alan.kullberg@motorola.com
Adrian Farrel Adrian Farrel
Old Dog Consulting Old Dog Consulting
Phone: +44 (0) 1978 860944 Phone: +44 (0) 1978 860944
Email: adrian@olddog.co.uk Email: adrian@olddog.co.uk
skipping to change at page 26, line 18 skipping to change at page 27, line 36
Phone: +1 408 383 7223 Phone: +1 408 383 7223
Email: andy.malis@tellabs.com Email: andy.malis@tellabs.com
Jean-Louis Le Roux Jean-Louis Le Roux
France Telecom France Telecom
2, avenue Pierre-Marzin 2, avenue Pierre-Marzin
22307 Lannion Cedex 22307 Lannion Cedex
France France
Email: jeanlouis.leroux@francetelecom.com Email: jeanlouis.leroux@francetelecom.com
10. Intellectual Property Consideration 11. Intellectual Property Consideration
The IETF takes no position regarding the validity or scope The IETF takes no position regarding the validity or scope of any
of any intellectual property or other rights that might be Intellectual Property Rights or other rights that might be claimed
claimed to pertain to the implementation or use of the to pertain to the implementation or use of the technology
technology described in this document or the extent to described in this document or the extent to which any license
which any license under such rights might or might not be under such rights might or might not be available; nor does it
available; neither does it represent that it has made any represent that it has made any independent effort to identify any
effort to identify any such rights. Information on the such rights. Information on the procedures with respect to rights
IETF's procedures with respect to rights in standards-track in RFC documents can be found in BCP 78 and BCP 79.
and standards-related documentation can be found in BCP-11.
Copies of claims of rights made available for publication
and any assurances of licenses to be made available, or the
result of an attempt made to obtain a general license or
permission for the use of such proprietary rights by
implementors or users of this specification can be obtained
from the IETF Secretariat.
The IETF invites any interested party to bring to its Copies of IPR disclosures made to the IETF Secretariat and any
attention any copyrights, patents or patent applications, or assurances of licenses to be made available, or the result of an
other proprietary rights which may cover technology that may attempt made to obtain a general license or permission for the use
be required to practice this standard. Please address the of such proprietary rights by implementers or users of this
information to the IETF Executive Director. specification can be obtained from the IETF on-line IPR repository
at http://www.ietf.org/ipr.
11. Full Copyright Statement The IETF invites any interested party to bring to its attention
any copyrights, patents or patent applications, or other
proprietary rights that may cover technology that may be required
to implement this standard. Please address the information to the
IETF at ietf-ipr@ietf.org.
Copyright (C) The Internet Society (2004). All Rights 11.1 IPR Disclosure Acknowledgement
Reserved.
This document and translations of it may be copied and By submitting this Internet-Draft, I certify that any applicable
furnished to others, and derivative works that comment on patent or other IPR claims of which I am aware have been disclosed,
or otherwise explain it or assist in its implementation may and any of which I become aware will be disclosed, in accordance with
be prepared, copied, published and distributed, in whole or RFC 3668.
in part, without restriction of any kind, provided that the
above copyright notice and this paragraph are included on
all such copies and derivative works. However, this
document itself may not be modified in any way, such as by
removing the copyright notice or references to the Internet
Society or other Internet organizations, except as needed
for the purpose of developing Internet standards in which
case the procedures for copyrights defined in the Internet
Standards process must be followed, or as required to
translate it into languages other than English.
The limited permissions granted above are perpetual and 12. Full Copyright Statement
will not be revoked by the Internet Society or its
successors or assigns. This document and the information Copyright (C) The Internet Society (2004). This document is
contained herein is provided on an "AS IS" basis and THE subject to the rights, licenses and restrictions contained in BCP
INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE 78, and except as set forth therein, the authors retain all their
DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT rights.
NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED This document and the information contained herein are provided
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
PURPOSE. REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND
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 End of changes. 

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