Avaya 580 - Manual (Page 580)

20-2 User Guide for the Avaya P580 and P882 Multiservice Switches, v6.1
Chapter 20
Router ports are ports that are attached to (or in the path to) multicast
routers and must be treated specially. All multicast traffic on a VLAN must
be forwarded to the router port.
Configuration of an Intelligent Multicast session first requires a session to
be established. Once that session is established, client and router ports can
be added to or removed from the session. Session and port configuration
can be done either manually or dynamically. Dynamic intelligent
multicasting is achieved through Internet Group Management Protocol
(IGMP) Snooping, and may also involve Lucent Group Membership
Protocol (LGMP), or Cisco Group Management Protocol (CGMP)
Snooping. All of the dynamic mechanisms are based on the assumption that
the client host is running IGMP, and is requesting membership in the IP
multicast session.
* Note: If there is no multicast session created for a multicast flow in a
VLAN, then that multicast flow will be flooded to all ports on
the VLAN. This is the default behavior for a bridge as
described in IEEE 802.1D. Intelligent multicasting must be
enabled for any dynamic intelligent multicasting to be active.
By default, the switch rate limits inter-router multicast traffic on all modules
that support rate limiting. If you need for your switch to support heavy
multicast traffic, disable rate limiting on ports that are connected to routers.
Also note that if high-bandwidth multicast streams are being used, rate
limiting will affect directly connected clients if that stream is not part of an
Intelligent Multicast session.
Manually Configured Intelligent Multicasting
Manual configuration of Intelligent Multicast sessions allows the network
administrator to dictate which multicast streams will be intelligently
multicasted. This method of configuration is also useful where dynamic
Intelligent Multicasting can not be used. Dynamic Intelligent Multicasting
can only be used in an environment that uses IGMP and an IP multicast
routing protocol (optional) to distribute multicast streams.
Dynamic Intelligent Multicasting
In an environment that uses IGMP (and an IP multicast routing protocol,
optionally), Dynamic Intelligent Multicasting may be used. The ability of
the switch to dynamically set up sessions and add or remove client and
router ports is particularly useful in a flexible multicast environment where
there are many multicast sessions to administer. The protocols and
mechanisms used to perform Intelligent Multicasting are enabled or
disabled across all VLANs on a switch. The Dynamic Intelligent
Multicasting process is split into three parts: Learning, Administration, and
Dissemination.