Core Based Trees (CBT version 3) Multicast Routing -- Protocol Specification --

Document Type Expired Internet-Draft (idmr WG)
Authors Anthony Ballardie  , Bradley Cain  , Zhaohui Zhang 
Last updated 1998-07-31
Stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Expired & archived
pdf htmlized bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Unknown
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This document describes the Core Based Tree (CBT version 3) network layer multicast routing protocol. CBT builds a shared multicast dis- tribution tree per group, and is suited to inter- and intra-domain multicast routing. CBT may use a separate multicast routing table, or it may use that of underlying unicast routing, to establish paths between senders and receivers. The CBT architecture is described in [1]. This specification supercedes and obsoletes RFC 2189. Changes from RFC 2189 include support for source specific joining and pruning to provide better CBT transit domain capability, new packet formats, and new robustness features. Section 1 documents the primary changes to RFC 2189. This document is progressing through the IDMR working group of the IETF. CBT related documents include [1, 2, 3, 5, 8]. For all IDMR- related documents, see


Anthony Ballardie (
Bradley Cain (
Zhaohui Zhang (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)