Network Working Group D. Ooms
Request for Comments: 3353 Alcatel
Category: Informational B. Sales
Alcatel
W. Livens
Colt Telecom
A. Acharya
IBM
F. Griffoul
Ulticom
F. Ansari
Bell Labs
August 2002
Overview of IP Multicast in a
Multi-Protocol Label Switching (MPLS) Environment
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2002). All Rights Reserved.
Abstract
This document offers a framework for IP multicast deployment in an
MPLS environment. Issues arising when MPLS techniques are applied to
IP multicast are overviewed. The pros and cons of existing IP
multicast routing protocols in the context of MPLS are described and
the relation to the different trigger methods and label distribution
modes are discussed. The consequences of various layer 2 (L2)
technologies are listed. Both point-to-point and multi-access
networks are considered.
Ooms, et al. Informational [Page 1]
RFC 3353 IP Multicast in an MPLS Environment August 2002
Table of Contents
1. Introduction ............................................. 3
2. Layer 2 Characteristics .................................. 4
3. Taxonomy of IP Multicast Routing Protocols
in the Context of MPLS ................................... 5
3.1. Aggregation .............................................. 5
3.2. Flood & Prune ............................................ 5
3.3. Source/Shared Trees ...................................... 6
3.4. Co-existence of Source and Shared Trees .................. 7
3.5. Uni/Bi-directional Shared Trees .......................... 10
3.6. Encapsulated Multicast Data .............................. 11
3.7. Loop-free-ness ........................................... 11
3.8. Mapping of Characteristics on Existing Protocols ......... 11
4. Mixed L2/L3 Forwarding in a Single Node .................. 12
5. Taxonomy of IP Multicast LSP Triggers .................... 14
5.1. Request Driven ........................................... 14
5.1.1. General .................................................. 14
5.1.2. Multicast Routing Messages ............................... 15
5.1.3. Resource Reservation Messages ............................ 15
5.2. Topology Driven .......................................... 16
5.3. Traffic Driven ........................................... 16
5.3.1. General .................................................. 16
5.3.2. An Implementation Example ................................ 17
5.4. Combinations of Triggers and Label Distribution Modes .... 18
6. Piggy-backing ............................................ 18
7. Explicit Routing ......................................... 20
8. QoS/CoS .................................................. 20
8.1. DiffServ ................................................. 20
8.2. IntServ and RSVP ......................................... 21
9. Multi-access Networks .................................... 21
10. More Issues .............................................. 22
10.1. TTL Field ................................................ 22
10.2. Independent vs. Ordered Label Distribution Control ....... 23
10.3. Conservative vs. Liberal Label Retention Mode ............ 24
10.4. Downstream vs. Upstream Label Allocation ................. 25
10.5. Explicit vs. Implicit Label Distribution ................. 25
11. Security Considerations .................................. 26
12. Acknowledgements ......................................... 26
Informative References........................................... 27
Authors' Addresses .............................................. 28
Full Copyright Statement ........................................ 30
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