Wireless Access Point
324 Configuring the Wireless AP
• for compatibility with ordinary operation, i.e., there is no 
optimization or modification of multicast traffic. 
• if you have an application where many subscribers need to see 
the multicast—a large enough number that it would be less 
efficient to convert to unicast and better just to send out multicast 
even though it must be sent out at the speed of the slowest 
connected station. 
An example of a situation that might benefit from the use of this 
mode is ghosting all the laptops in a classroom using multicast. One 
multicast stream at, say, 6 Mbps is probably more efficient than thirty 
unicast streams.
The next three options convert multicast to unicast. Packets are sent 
directly to the stations at the best possible data rates. This approach 
significantly improves the quality of the voice and video multicast 
streams.
• Convert to unicast and send unicast packets to all stations. This 
may be useful in link-local multicast situations.
• Convert to unicast, snoop IGMP, and only send to stations 
subscribed (send as multicast if no subscription). This option is 
useful when you need to stream voice or video multicast traffic to all 
stations, but some stations are capable of subscribing to multicast 
groups while other stations are not. The stations that do not subscribe 
will not benefit from conversion to unicast; their video or voice 
quality may be compromised. 
• Convert to unicast, snoop IGMP, and only send to stations 
subscribed (don't send packet if no subscription). This option is 
useful in well controlled environments when you need to stream 
voice or video multicast traffic only to stations that are capable of 
subscribing to multicast groups and there is no need for the rest of the 
stations to receive the data stream.
21. Multicast Exclude: This is a list of multicast IP addresses that will not be 
subject to multicast-to-unicast conversion. This list is useful on networks 
where applications such as those using multicast Domain Name System