partition your network to ensure that a multicast sent by one RAP is not received by another RAP
on the same Ethernet segment and then sent back into the network.
If 802.11b clients need to receive CAPWAP multicasts, then multicast must be enabled
globally on the controller as well as on the mesh network (using the
config network
multicast global enable
CLI command). If multicast does not need to extend to 802.11b
clients beyond the mesh network, the global multicast parameter should be disabled
(using the
config network multicast global disable
CLI command).
Note
Enabling Multicast on the Mesh Network (CLI)
To enable multicast mode on the mesh network to receive multicasts from beyond the mesh networks, enter
these commands:
config network multicast global enable
config mesh multicast
{
regular
|
in
|
in-out
}
To enable multicast mode only the mesh network (multicasts do not need to extend to 802.11b clients beyond
the mesh network), enter these commands:
config network multicast global disable
config mesh multicast
{
regular
|
in
|
in-out
}
Multicast for mesh networks cannot be enabled using the controller GUI.
Note
IGMP Snooping
IGMP snooping delivers improved RF usage through selective multicast forwarding and optimizes packet
forwarding in voice and video applications.
A mesh access point transmits multicast packets only if a client is associated with the mesh access point that
is subscribed to the multicast group. So, when IGMP snooping is enabled, only that multicast traffic relevant
to given hosts is forwarded.
To enable IGMP snooping on the controller, enter the following command:
configure network multicast igmp snooping enable
A client sends an IGMP
join
that travels through the mesh access point to the controller. The controller
intercepts the
join
and creates a table entry for the client in the multicast group. The controller then proxies
the IGMP
join
through the upstream switch or router.
You can query the status of the IGMP groups on a router by entering the following command:
router#
show ip gmp groups
IGMP Connected Group Membership
Group Address
Interface
Uptime
Expires
Last Reporter
Cisco Mesh Access Points, Design and Deployment Guide, Release 7.3
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183
Connecting the Cisco 1500 Series Mesh Access Points to the Network
IGMP Snooping
