Riverstone Networks WICT1-12 - Manual (Page 465)

Riverstone Networks RS Switch Router User Guide Release 8.0 19-1
19 MULTICAST ROUTING
CONFIGURATION
Multicast routing on the RS 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
RS’s.
This chapter:
• Provides an overview of the RS’s implementation of the Internet Group Management Protocol
(IGMP)
• Provides an overview of the RS’s implementation of the Distance Vector Multicast Routing
Protocol (DVMRP)
• Discusses configuring DVMRP routing on the RS
• Discusses configuring IGMP on the RS
19.1 IGMP OVERVIEW
The RS 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 RS, 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.
The RS allows per-interface control of the host query interval and response time. Query interval defines the time
between IGMP queries. Response time defines the time the RS will wait for host responses to IGMP queries. The
RS can be configured to deny or accept group membership filters.
19.2 DVMRP OVERVIEW
DVMRP is an IP multicast routing protocol. On the RS, DVMRP routing is implemented as specified in the
draft-ietf-idmr-dvmrp-v3-06.txt
file, which is an Internet Engineering Task Force (IETF) document.
The RS’s implementation of DVMRP supports the following:
• The mtrace utility, which racks the multicast path from a source to a receiver.
• Generation identifiers, which are assigned to DVMRP whenever that protocol is started on a
router.
• Pruning, which is an operation DVMRP routers perform to exclude interfaces not in the shortest
path tree.