01-27-2009 09:54 AM - edited 03-15-2019 03:48 PM
CME 7.0(1) on 2811
3560G 24 Port PoE switch
The ports on the 3560G were very chatty, which I assumed was from the Multicast MoH stream send by CME. I configured IP Multicast routing on the voice VLAN for both the 2811 and 3560G. The excess traffic on the 3560G has subsided except the Ethernet trunk that links the 3560G and 2811 is still extremely chatty.
Should I be concerned or is this normal behavior?
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01-27-2009 01:24 PM
CME by default will just start streaming the multicast when it is configured. It isn't 'kicked off' when MoH is called like one may expect.
In this scenario, the router is a simple multicast source. Meaning, you don't even need full multicast configuration on it. In this situation, it means that CME will stream the MoH towards the switch. This means your best case scenario is MoH on your trunk at all times, plus the ports for the IP phones.
hth,
nick
01-27-2009 10:14 AM
We find that in many cases we require to turn off IGMP snooping in order to get CME multicast to work.
This is because the phone does not send an IGMP join message to join the stream. Because of this, the switch floods it everywhere, all the time.
When the phone is told to listen to multicast, it just changes it's listen port to listen to the multicast.
hth,
nick
01-27-2009 12:48 PM
Nick,
I disabled IGMP snooping on the 3560G and the switchports went back to being chatty.
MoH works fine. I am just concerned about the chatty trunk port.
Do you have any other suggestions?
01-27-2009 01:24 PM
CME by default will just start streaming the multicast when it is configured. It isn't 'kicked off' when MoH is called like one may expect.
In this scenario, the router is a simple multicast source. Meaning, you don't even need full multicast configuration on it. In this situation, it means that CME will stream the MoH towards the switch. This means your best case scenario is MoH on your trunk at all times, plus the ports for the IP phones.
hth,
nick
01-27-2009 01:49 PM
Nick,
I checked the counters on the switchport, plus periodically checked cpu utilization and they are all minimal. I guess I was just being paranoid.
Thank you for the insight.
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