Intra-LIS IP multicast among routers over ATM using Sparse Mode PIM (RFC2337)
Original Publication Date: 1998-Apr-01
Included in the Prior Art Database: 2019-Feb-15
Internet Society Requests For Comment (RFCs)
D. Farinacci: AUTHOR [+2]
This document describes how intra-LIS IP multicast can be efficiently supported among routers over ATM without using the Multicast Address Resolution Server (MARS). This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested.
Network Working Group D. Farinacci Request for Comments: 2337 Cisco Systems Category: Experimental D. Meyer Cisco Systems Y. Rekhter Cisco Systems April 1998
Intra-LIS IP multicast among routers over ATM using Sparse Mode PIM
Status of this Memo
This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (1998). All Rights Reserved.
This document describes how intra-LIS IP multicast can be efficiently supported among routers over ATM without using the Multicast Address Resolution Server (MARS). The method described here is specific to Sparse Mode PIM [PIM-SM], and relies on the explicit join mechanism inherent in PIM-SM to notify routers when they should create group specific point-to-multipoint VCs.
3. Overall model
This document focuses on forwarding of multicast traffic among PIM-SM routers connected to an ATM network. Routers on an ATM network are partitioned into Logical IP Subnets, or LISs. This document deals with handling multicast within a single LIS. Handling inter-LIS multicast traffic, including handling shortcuts, is outside the scope of this document. In addition, this document does not address forwarding of multicast traffic to or from hosts connected to an ATM network.
Farinacci, et. al. Experimental [Page 1]
RFC 2337 IP multicast over ATM using PIM April 1998
4. Router behavior
This document requires that each router within a LIS knows IP and ATM addresses of all other routers within the LIS. The mapping between IP and ATM addresses may be provided by an ARP server [RFC2225], or by any other means (e.g., static configuration).
Each PIM router within a LIS is required to maintain a single (shared) point-to-multipoint distribution VC rooted at the router with all other PIM routers in the LIS as the leaf nodes. The VC is expected to be used for forwarding of multicast traffic (both data and control) among routers within the LIS. For example, this VC would be used for distributing PIM [PIM-SM] control messages (Join/Prune messages).
In addition, if a PIM router receives a IGMP report from an non-PIM neighbor, then the router may add the reporter to the existing shared distribution VC or to the group specific distribution VC (if it exists). The PIM router may also create a specific VC for this IGMP proxy.
4.1. Establishing Dedicated, Per Group Point-to-Multipoint VCs
Routers may also maintain group specific, dedicated point-to- multipoint VCs. In particular, an upstream router for a group may choose to become the root of a group specific point-to-multipoint VC whose leaves are the downstream routers that have directly connected or downstream receivers for the group. While the criteria for establishing a group specific point-to-multipoint VC are local to a router, issues such as the volume of traffic associat...