Cisco 877w - Apple devices not able to see wired apple TV

[davidfield]

Hello All,

Can anyone point me to a doc or forum discussion on how to setup the wireless interface to forward multicast packets?  Basically I cant get the ipads etc.. to see the AppleTV to control it.  I connected an AP and it works fine so its got to be something with the way the router handles the packets from teh integrated wireless interface.  I've been searching the forum for about 1hr and haven't founf anything other than a breif mention of broadcast forwarding and multicast setup.

Has anyone got anything more complrehensive I can read?

Thanks

David

[manbaez]

Hello David,

Thank you for contacting the Sales Acceleration Center (SAC) regarding your recent inquiry, Case Number

Case Description:

Cisco 877w - Apple devices not able to see wired apple TV

Case Solution:

The Bonjour service uses multicast to advertise your Home Sharing enabled device to the local network. In my case the Cisco 877W I was using had a Layer 3 enabled BVI (Bridged Virtual Interface) to which the Wireless Dot11Radio interface was not fowarding multicast packets properly.

First of all, obtain the Multicast groups your wireless adapter is configured for (on Windows open a command prompt and run the below command):

The result will give you an output as per below, we are interested in the multicast address directly after the 224.0.0.252 address 239.255.255.250:

Then we need to enable multicast routing on the router, connect to your router and enter config terminal mode:

Next we will configure IGMP v3 and add the relevant Wireless interface on your router to the correct multicast address group:

Next perform the same config your BVI interface:

Once complete save your changes and confirm both interfaces have been added to the multicast groups using the command sh ip igmp group:

You now need to reload your router and restart iTunes and then attempt to connect to Home Sharing from your Apple TV.

Other commands that I used to troubleshoot with were:
debug ip mpacket - Multicast Packet Debugging
debug ip mroute - Debug Multicast Routing
sh ip mroute - Show IP Multicast Routes

By default the Cisco implementation of a Dot11Radio interface and a BVI interface don't appear to forward multicast packets between each other. Seems odd to me as they're both in the same L2 bridging group..anyway.

I am going to close the case for this specific inquiry on my side. If you need moere information Please feel free to reach out to me or any member of the SAC team if we can be of any further assistance or if you have any other related questions in the future. We strive to provide you with excellent service. We value your input and look forward to serving you moving forward.