Cabletron Systems SmartSwitch Router 9032578-02 - Manual (Page 143)

SmartSwitch Router User Reference Manual 143
Chapter 8
Multicast Routing
Configuration
Guide
IP Multicast Overview
Multicast routing on the SSR is supported through DVMRP and IGMP. IGMP is used to
determine host membership on directly attached subnets. DVMRP is used to determine
forwarding of multicast traffic between SSRs.
This chapter:
• Provides an overview of the SSR’s implementation of the Internet Group Management
Protocol (IGMP)
• Provides an overview of the SSR’s implementation of the Distance Vector Multicast
Routing Protocol (DVMRP)
• Discusses configuring DVMRP routing on the SSR
• Discusses configuring IGMP on the SSR.
IGMP Overview
The SSR supports IGMP Version 2.0 as defined in RFC 2236. IGMP is run on a per-IP
interface basis. An IP interface can be configured to run just IGMP and not DVMRP. Since
multiple physical ports (VLANs) can be configured with the same IP interface on the SSR,
IGMP keeps track of multicast host members on a per-port basis. Ports belonging to an IP
VLAN without any IGMP membership will not be forwarded any multicast traffic.