Configuration C3560x and UC520

[HustadtMartin]

Hi Guys,

i have a design related question and i hope someone can give me an advice ;-)

Let me start with some infrastructure details ...

Cisco C2901 as our Main Router

Cisco UC520 as Communication Platform

Cisco C3560x as Core-Switch

VLAN 10 : Data

VLAN 100 : VOICE

Everything is working but i m not sure if the switchport config is right in that way.

As an example :

interface GigabitEthernet 0/6

switchport access vlan 10

switchport mode access

switchport voice vlan 100

spanning-tree portfast

When we connect an Cisco 7971g and an pc everything is working fine. But when i start wireshark on the pc behind the phone you see a lot of UDP Traffic source UC520 destination 239.10.16.8 or 239.10.16.16. At this point i m getting confused. So i start looking for the cisco phone config, VLAN ID on the phone is 100 (i think that is ok) but the PC-VLAN part is empty?!?

The main thing is, how can i stop this cisco-sccp traffic on the pc port (prtg shows me a average of 200 kbit/s) i think it is an config fault.

Thanks in advance

[paolo bevilacqua]

That can be MoH send by UC500 on all interfaces. You do not have to worry, it's nigligible amount  and it does not cause any problem.

[HustadtMartin]

Ok,

but is there no way to disable that kind of traffic? I´m not happy with that kind of behavior.

Why is this kind of traffic not seperated by vlan 100?

Thanks

[paolo bevilacqua]

Because IP phones can be in any subnet, or VLAN.

[acampbell]

Martin,

As Paolo has stated.

The address 239.... is a multicast address this will traverse both your voice and data vlans to

allow both ip phones or softphones like Cisco Ip communicator to use music on hold.

The wireshark will see this as SCCP as the the default for MOH on CCME/UC500 is to use UDP port 2000.

Like Paolo says just ignore this traffic 200K on a 100M interface is about 0.2 %

Regards,
Alex.
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