5508 Controller & Muliticast

[WorcesterAcademy]

have a Cisco 5508 controller (version 6.0.199.4) that when I enable global multicast mode it will work for an hour or two and then it will kill the network.  All internet both wired and wireless, access to server everything dead.  I then have to directly connect to the service port and disable the global multicast mode.  Then two reasons for enabling it are Docs2Go and LanSchool both require multicast to be enabled.  I have it enabled on our wired network and it works OK there.  I am probably just missing something stupid.  Any thoughts or suggestions would be greatly appreciated.

[Stephen Rodriguez]

Take a look at

https://supportforums.cisco.com/docs/DOC-14713

HTH,

Steve

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[WorcesterAcademy]

Thanks. That doc was helpful in explaining in simple details about multicast.  However I am stii having the same issue above. 

[Stephen Rodriguez]

what address are you assigning to the WLC?  it should be an unused 239.x.x.x address. 

What else is running multicast? 

Are you running in dense or sparse mode?

is IGMP snooping enabled?

next time this happens, instead of disabling multicast on the WLC, shut down the port/port-channel to the WLC.

[WorcesterAcademy]

Thanks for the things to check.

1.  Where would I assign the 239.x.x.x address on the controller?

2. Just my switches are running multicast (seems to be working fine for a while now)

3. i am running sparse mode.

4. No IGMP is not enable

If I shutdown the port/port channel to the controller will The access points still function and allow internet access?

Thanks Again

[Stephen Rodriguez · Accepted solution]

On the Controller tab.

so if you're not setting a multicast address, then you are running in Unicast mode. 

Multicast - Unicast - This is the easiest method to use.  When the WLC receives a Multicast packet, it replays that packet to every AP that is connected.   Now this does work, but can be very network intense, as every AP gets  the stream.  So if you have 100 AP, there are 100 streams, 300 AP 300  streams.

Mulicast  - Multicast - This is the better method to use.  With this method, the  AP will join to a multicast group, that you configure, preferably in the  239.x.x.x administratively scoped space.  Now when the WLC gets a  mutlicast packet, it replays it once to the group.

Now,  the WLC side is easy.  Select Mutlicast - Multicast and configure your  group, each WLC in your mobility group should use a unique address.  For  the WLC you are done.

HTH,

Steve

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[WorcesterAcademy]

Ok I think I got it now.  I am going to change AP multicast mode from unicast to multicast under the controller - general tab. I also an going to enable the global multicast mode, enable IGMP Snooping and set the multicast IP to an unused 239.x.x.x address.  Sound about right?

[Stephen Rodriguez]

sounds like a plan!  let me know if it fixes the issue.

HTH,

Steve

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[WorcesterAcademy]

Will do....I will not get to try it until next week,  but I will for sure let you know how it goes.

[WorcesterAcademy]

That solved my problem....Thanks for all your help!

[Stephen Rodriguez]

awesome. Can you plead mark this question as answered? It makes it easier to find for others having this type of issue.

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