draft-ietf-pim-rpf-vector-02.txt   draft-ietf-pim-rpf-vector-03.txt 
PIM WG IJ. Wijnands PIM WG IJ. Wijnands
Internet-Draft A. Boers Internet-Draft A. Boers
Expires: August 5, 2006 E. Rosen Intended status: Informational E. Rosen
Cisco Systems, Inc. Expires: April 4, 2007 Cisco Systems, Inc.
february 2006 october 2006
The RPF Vector TLV The RPF Vector TLV
draft-ietf-pim-rpf-vector-02 draft-ietf-pim-rpf-vector-03
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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This Internet-Draft will expire on August 5, 2006. This Internet-Draft will expire on April 4, 2007.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). Copyright (C) The Internet Society (2006).
Abstract Abstract
This document describes a use of the PIM Join Attribute as defined in This document describes a use of the PIM Join Attribute as defined in
draft-ietf-pim-join-attributes[I-D.ietf-pim-join-attributes] which draft-ietf-pim-join-attributes[I-D.ietf-pim-join-attributes] which
enables PIM to build multicast trees through an MPLS-enabled network, enables PIM to build multicast trees through an MPLS-enabled network,
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Use of the RPF Vector TLV . . . . . . . . . . . . . . . . . . 4 2. Use of the RPF Vector TLV . . . . . . . . . . . . . . . . . . 4
2.1. Attribute and shared tree joins . . . . . . . . . . . . . 4 2.1. Attribute and shared tree joins . . . . . . . . . . . . . 4
2.2. Attribute and Bootstrap messages . . . . . . . . . . . . . 5 2.2. Attribute and Bootstrap messages . . . . . . . . . . . . . 5
2.3. The Vector Attribute . . . . . . . . . . . . . . . . . . . 5 2.3. The Vector Attribute . . . . . . . . . . . . . . . . . . . 5
2.3.1. Inserting a Vector Attribute in a Join . . . . . . . . 5 2.3.1. Inserting a Vector Attribute in a Join . . . . . . . . 5
2.3.2. Processing a Received Vector Attribute . . . . . . . . 5 2.3.2. Processing a Received Vector Attribute . . . . . . . . 5
2.3.3. Vector Attribute and Asserts . . . . . . . . . . . . . 5 2.3.3. Vector Attribute and Asserts . . . . . . . . . . . . . 5
3. Vector Attribute TLV Format . . . . . . . . . . . . . . . . . 7 3. Vector Attribute TLV Format . . . . . . . . . . . . . . . . . 7
4. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5.1. Normative References . . . . . . . . . . . . . . . . . . . 7 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8
5.2. Informative References . . . . . . . . . . . . . . . . . . 8 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.1. Normative References . . . . . . . . . . . . . . . . . . . 8
7.2. Informative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
Intellectual Property and Copyright Statements . . . . . . . . . . 10 Intellectual Property and Copyright Statements . . . . . . . . . . 10
1. Introduction 1. Introduction
It is sometimes convenient to distinguish the routers of a particular It is sometimes convenient to distinguish the routers of a particular
network into two categories: "edge routers" and "core routers". The network into two categories: "edge routers" and "core routers". The
edge routers attach directly to users or to other networks, but the edge routers attach directly to users or to other networks, but the
core routers attach only to other routers of the same network. If core routers attach only to other routers of the same network. If
the network is MPLS-enabled, then any unicast packet which needs to the network is MPLS-enabled, then any unicast packet which needs to
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as they handle only tunneled packets, they only need to know how to as they handle only tunneled packets, they only need to know how to
reach the edge routers and the other core routers. reach the edge routers and the other core routers.
Consider, for example, the case where the network is an Autonomous Consider, for example, the case where the network is an Autonomous
System (AS), the edge routers are EBGP speakers, the core routers may System (AS), the edge routers are EBGP speakers, the core routers may
be said to constitute a "BGP-free core". The edge routers must be said to constitute a "BGP-free core". The edge routers must
distribute BGP routes to each other, but not to the core routers. distribute BGP routes to each other, but not to the core routers.
However, when multicast packets are considered, the strategy of However, when multicast packets are considered, the strategy of
keeping the core routers free of "external" routes is more keeping the core routers free of "external" routes is more
problematic. When using PIM-SM[I-D.ietf-pim-sm-v2-new], PIM-SSM[I- problematic. When using PIM-SM[RFC4601], PIM-SSM[I-D.ietf-ssm-arch]
D.ietf-ssm-arch] or PIM-BIDIR[I-D.ietf-pim-bidir] to create a or PIM-BIDIR[I-D.ietf-pim-bidir] to create a multicast distribution
multicast distribution tree for a particular multicast group, one tree for a particular multicast group, one wants the core routers to
wants the core routers to be full participants in the PIM protocol, be full participants in the PIM protocol, so that multicasting can be
so that multicasting can be done efficiently in the core.This means done efficiently in the core.This means that the core routers must be
that the core routers must be able to correctly process PIM Join able to correctly process PIM Join messages for the group, which in
messages for the group, which in turn means that the core routes must turn means that the core routes must be able to send the Join
be able to send the Join messages towards the root of the messages towards the root of the distribution tree. If the root of
distribution tree. If the root of the tree lies outside the the tree lies outside the network's borders (e.g., is in a different
network's borders (e.g., is in a different AS), and the core routers AS), and the core routers do not maintain routes to external
do not maintain routes to external destinations, then the PIM Join destinations, then the PIM Join messages cannot be processed, and the
messages cannot be processed, and the multicast distribution tree multicast distribution tree cannot be created.
cannot be created.
In order to allow PIM to work properly in an environment where the In order to allow PIM to work properly in an environment where the
core routers do not maintain external routes, a PIM extension is core routers do not maintain external routes, a PIM extension is
needed. When an edge router sends a PIM Join message into the core, needed. When an edge router sends a PIM Join message into the core,
it must include in that message a "Vector" which specifies the IP it must include in that message a "Vector" which specifies the IP
address of the next edge router along the path to the root of the address of the next edge router along the path to the root of the
multicast distribution tree. The core routers can then process the multicast distribution tree. The core routers can then process the
Join message by sending it towards the specified edge router (i.e., Join message by sending it towards the specified edge router (i.e.,
toward the Vector). In effect, the Vector serves as an attribute, toward the Vector). In effect, the Vector serves as an attribute,
within a particular network, for the root of the tree. within a particular network, for the root of the tree.
This document defines a new TLV in the PIM Join Attribute message[I- This document defines a new TLV in the PIM Join Attribute
D.ietf-pim-join-attributes]. It consists of a single Vector which message[I-D.ietf-pim-join-attributes]. It consists of a single
identifies the exit point of the network. Vector which identifies the exit point of the network.
2. Use of the RPF Vector TLV 2. Use of the RPF Vector TLV
Before we can start forwarding multicast packets we need to build a Before we can start forwarding multicast packets we need to build a
forwarding tree by sending PIM Joins hop by hop. Each router in the forwarding tree by sending PIM Joins hop by hop. Each router in the
path creates a forwarding state and propagates the Join towards the path creates a forwarding state and propagates the Join towards the
root of the forwarding tree. The building of this tree is receiver root of the forwarding tree. The building of this tree is receiver
driven. See Figure 1. driven. See Figure 1.
------------------ BGP ----------------- ------------------ BGP -----------------
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---- ----
The Vector Attribute type is 0. The Vector Attribute type is 0.
Length Length
------ ------
Length depending on Address Family of Encoded-Unicast address. Length depending on Address Family of Encoded-Unicast address.
Value Value
----- -----
Encoded-Unicast address, see PIM-SM Encoded-Unicast address, see PIM-SM
[I-D.ietf-pim-sm-v2-new] [RFC4601]
4. Acknowledgments 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|F|S| Type | Length | Encoded-Unicast address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-.......
F bit
-----
Forward Unknown TLV. If this bit is set the TLV is forwarded
regardless if the router understands the Type.
S bit
-----
Bottom of Stack. If this bit is set then this is the last
TLV in the stack.
Type
----
The Vector Attribute type is 0.
Length
------
Length depending on Address Family of Encoded-Unicast address.
Value
-----
Encoded-Unicast address, see PIM-SM
4. IANA Considerations
An attribute type needs to be assigned. For now we propose the value
0.
5. Security Considerations
Security of the RPF Vector Attribute is only guaranteed by the
security of the PIM packet, so the security considerations for PIM
join packets as described in PIM-SM [RFC4601] apply here.
6. Acknowledgments
The authors would like to thank Yakov Rekhter and Dino Farinacci for The authors would like to thank Yakov Rekhter and Dino Farinacci for
their initial ideas on this topic. their initial ideas on this topic.
5. References 7. References
5.1. Normative References 7.1. Normative References
[I-D.ietf-pim-sm-v2-new] [RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, "Protocol Independent Multicast - Sparse Mode (PIM-SM):
"Protocol Independent Multicast - Sparse Mode PIM-SM): Protocol Specification (Revised)", RFC 4601, August 2006.
Protocol Specification (Revised)",
draft-ietf-pim-sm-v2-new-11 (work in progress),
October 2004.
[I-D.ietf-pim-bidir] [I-D.ietf-pim-bidir]
Handley, M., Kouvelas, I., Speakman, T., and L. Vicisano, Handley, M., Kouvelas, I., Speakman, T., and L. Vicisano,
"Bi-directional Protocol Independent Multicast (BIDIR- "Bi-directional Protocol Independent Multicast (BIDIR-
PIM)", draft-ietf-pim-bidir-07 (work in progress), PIM)", draft-ietf-pim-bidir-07 (work in progress),
March 2005. March 2005.
[I-D.ietf-pim-join-attributes] [I-D.ietf-pim-join-attributes]
Boers, A., "Format for using TLVs in PIM messages", Boers, A., "Format for using TLVs in PIM messages",
draft-ietf-pim-join-attributes-00 (work in progress), draft-ietf-pim-join-attributes-00 (work in progress),
October 2005. October 2005.
[I-D.ietf-ssm-arch] [I-D.ietf-ssm-arch]
Holbrook, H. and B. Cain, "Source-Specific Multicast for Holbrook, H. and B. Cain, "Source-Specific Multicast for
IP", draft-ietf-ssm-arch-06 (work in progress), IP", draft-ietf-ssm-arch-06 (work in progress),
September 2004. September 2004.
5.2. Informative References 7.2. Informative References
Authors' Addresses Authors' Addresses
IJsbrand Wijnands IJsbrand Wijnands
Cisco Systems, Inc. Cisco Systems, Inc.
De kleetlaan 6a De kleetlaan 6a
Diegem 1831 Diegem 1831
Belgium Belgium
Email: ice@cisco.com Email: ice@cisco.com
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Email: aboers@cisco.com Email: aboers@cisco.com
Eric Rosen Eric Rosen
Cisco Systems, Inc. Cisco Systems, Inc.
1414 Massachusetts Avenue 1414 Massachusetts Avenue
Boxborough, Ma 01719 Boxborough, Ma 01719
Email: erosen@cisco.com Email: erosen@cisco.com
Intellectual Property Statement Full Copyright Statement
Copyright (C) The Internet Society (2006).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
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The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
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ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is provided by the IETF
Internet Society. Administrative Support Activity (IASA).
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