multicasting over Cisco Aironet 1200 AP

c.ong · ‎05-08-2007

Hi Sir,

My customer is trying to implement video streaming using multicast over AP 1200 but the video is too jittery and the delay is too much. The visualization is unacceptable.

Kindly suggest what can be the problem in it ? He doubt the Access Point isn't capable of forwarding multicast packets. He is using a simple network with Cisco access point and trying to stream video with VLC.

The setup is only one source connected straight to the AP using a cross cable. Only one wireless user is connected to AP.

However, video streaming using unicast is fine.

Thanks.

-Delon

john.preves · ‎05-12-2007

Keep in mind hat you only have between 5.5 and maybe 22Mbps of actual throughput, depending on how close you are to the AP. Also, this is shared and it is half duplex! Multicast introduces a lot of traffic to a device and I think that your issue may not be that the AP cannot forward multicasts, it just can't handle the amount of juice required.

It works fine using unicast, as you said. Sounds like you fixed it right there!

bmennenga · ‎05-15-2007

Cisco AP12xx do not support multicast the same as unicast. Multicast is a much larger load on an AP. CPU and Bandwidth cycles get used very quickly. We attempted video multicast over AP1242 and it failed miserably, but worked great unicast. In the end we had to go to another product that allowed you to statically control the multicast. The problem with the Cisco AP and most vender APs is that it will send the multicast traffic to every client on the AP individually. So 2 clients means the stream is replicated X2. 5 clients X5 traffic. Also the CPU becomes maxed with only a couple megs of multicast traffic.

c.ong · ‎05-15-2007

HI Brian,

Thanks for your info. Can you let me know the product you used which can perform better in multicast?

Thank you.

-delon