4-17
Cisco Wireless LAN Controller Configuration Guide
Ol-9141-03
Chapter 4 Configuring Controller SettingsWireless Device Access
Configuring Client Roaming
•
When you enable multicast mode on the controller you also must configure an LWAPP multicast
group address on the controller. Access points subscribe to the LWAPP multicast group using IGMP.
•
Cisco 1100, 1130, 1200, 1230, and 1240 access points use IGMP versions 1, 2, and 3. However,
Cisco 1000 series access points use only IGMP v1 to join the multicast group.
•
Multicast mode works only in Layer 3 LWAPP mode.
•
Access points in monitor mode, sniffer mode, or rogue detector mode do not join the LWAPP
multicast group address.
•
When using Multiple controllers on the network, make sure that the same multicast address is
configured on all the controllers.
•
Multicast mode does not work across intersubnet mobility events such as guest tunneling,
site-specific VLANs, or interface override using RADIUS. However, multicast mode does work in
these subnet mobility events when you disable the Layer 2 IGMP snooping/CGMP features on the
wired LAN.
•
The controller drops any multicast packets sent to the UDP port numbers 12222, 12223, and 12224.
Make sure the multicast applications on your network do not use those port numbers.
•
Multicast traffic is transmitted at 6 Mbps in an 802.11a network. Therefore, if several WLANs
attempt to transmit at 1.5 Mbps, packet loss occurs, which breaks the multicast session.
Enabling Multicast Mode
Multicasting is disabled by default. Use the commands in
Table 4-2
to configure multicast mode on the
controller CLI.
You can also enable multicast mode on the Configure > Switch IP System General page on the WCS
interface.
Configuring Client Roaming
The Cisco UWN Solution supports seamless client roaming across lightweight access points managed
by the same controller, between controllers in the same mobility group on the same subnet, and across
controllers in the same mobility group on different subnets.
Note
In controller software release 4.0.206.0 and later, client roaming with multicast is supported.
Table 4-2
CLI Commands for Configuring Multicast Mode
Command
Multicast Mode
config network multicast global
{
enable
|
disable
}
Enable or disable multicasting
config network multicast mode unicast
Configure the controller to use the unicast method
to send multicast packets
config network multicast mode multicast
multicast-group-ip-address
Configure the controller to use the multicast
method to send multicast packets to an LWAPP
multicast group.