Adding The Router Stack To A Multicast Group; Altering Igmp Query Intervals - HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual

Configuring Multicast Support for a Stub Network
Configuring IGMP Proxy for Multicast Stub Routing Support
10-16
The router at the remote endpoint removes the GRE header from the packet
and forwards the multicast packet through the correct interfaces to members
of the multicast host group.
You can configure the tunnel interface as an upstream interface. The tunnel
will then receive multicasts from the multicast source for clients connected
to the router.
You should enable PIM-SM on the tunnel interface on the remote multicast
router.
See Chapter 9: Configuring a Tunnel with Generic Routing Encapsulation
to learn more about configuring a GRE tunnel.

Adding the Router Stack to a Multicast Group

The ProCurve Secure Router typically distinguishes between multicast pack-
ets delivering actual data and IGMP packets, which are also destined for
multicast addresses. To save processing power, the router processes IGMP
packets only, simply forwarding the multicast packets without processing
them.
When troubleshooting, you can have the router itself join a multicast host
group. The router becomes a host in the multicast group and begins to process
all multicast packets. It can then answer Internet Control Message Protocol
(ICMP) echo requests and respond to pings sent to the multicast address. To
have the router join a multicast group, enter this command from the global
configuration mode context:
Syntax: ip igmp join <A.B.C.D>
Replace <A.B.C.D> with the IP address of the multicast group. For example:
ProCurve(config)# ip igmp join 239.255.0.234
Having the router join a multicast host group can be useful for troubleshoot-
ing. You can use the ping and debug commands to determine the node that
fails to forward multicast messages.

Altering IGMP Query Intervals

IGMP involves trade-offs. The protocol contains packets by giving multicast
routers up-to-date information on which networks actually need specific
multicasts. On the other hand, the IGMP queries that maintain this information
also consume bandwidth.