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BEST MULTICAST SOURCE SELECTION FOR THE SAME MULTICAST GROUP

IP.com Disclosure Number: IPCOM000238501D
Publication Date: 2014-Aug-29
Document File: 3 page(s) / 350K

Publishing Venue

The IP.com Prior Art Database

Related People

Santosh Mundhe: AUTHOR [+2]

Abstract

Internet Group Management Protocol v2 (IGMPv2) does not specify the source and receiver to receive traffic from all multicast sources. With the solution presented herein, the last hop router (where the receivers are connected) can select the best multicast source based on administrative distance/metric and lowest Reverse Path Forwarding (RPF) neighbor if required. It will maintain the next best available multicast source (S,G) as backup in its multicast table.

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BEST MULTICAST SOURCE SELECTION FOR THE SAME MULTICAST GROUP

AUTHORS:

Santosh Mundhe Rajkumar S

CISCO SYSTEMS, INC.

ABSTRACT

    Internet Group Management Protocol v2 (IGMPv2) does not specify the source and receiver to receive traffic from all multicast sources. With the solution presented herein, the last hop router (where the receivers are connected) can select the best multicast source based on administrative distance/metric and lowest Reverse Path Forwarding (RPF) neighbor if required. It will maintain the next best available multicast source (S,G) as backup in its multicast table.

DETAILED DESCRIPTION

    In a scenario with multiple sources in Protocol Independent Multicast Sparse Mode (PIM SM) for the same multicast group address, the Rendezvous Point (RP) does not decide from which source to take the multicast stream. The RP joins the Shortest-Path (SP)-Tree to each source router and forwards the traffic from both sources. Internet Group Management Protocol v2 (IGMPv2) can only request a multicast group, it cannot specify the source. If IGMPv2 is used, and a PC requests group 225.100.100.100, and there are 5 sources sending to this group, the PC will receive traffic from all 5 sources. This is not a problem in PIM Source Specific Multicast (SSM) with IGMPv3 where receiver defines the source.

    Presented herein is a solution for IGMPv2 with PIM SM to avoid duplicate traffic in a scenario with multiple sources for the same multicast group address. A similar solution can be applied for PIM Dense Mode (DM) as well.

    Reference is made to FIG. 1 below. This solution helps with IGMPv2 to receive multicast group traffic from the best source based on a metric to reach towards the source. The last hop router will have information from the shared t...