Cisco Support Community
Community Member

Correct Config for CME connection to Switch


Could anyone tell me if this config looks OK

I am setting up the Interfaces for both our CME 2821 Router and C3560 Switch

The CME Router has IP address, our 3950 switch uses VLAN 20 for voice and the native VLAN for data.

So far I have:

For the CME Router port connected to the Switch

interface GigabitEthernet0/0

ip address

h323-gateway voip interface

h323-gateway voip bind srcaddr

For the Switch Port connected to the Router:

interface GigabitEthernet0/1

switchport access vlan 20

switchport mode access

srr-queue bandwidth share 10 10 60 20

srr-queue bandwidth shape 10 0 0 0

queue-set 2

mls qos trust cos

auto qos voip trust

Is QOS required for the Switch connection to the Router, or can I remove it?

Also Do I need spanning-tree portfast on the interface?




Re: Correct Config for CME connection to Switch

if u have tow vlans where u do intervlan routing

on the switch or the router

if it is in the router u need to make switch link to the router as trunk and in the router inter face creat two subinterfaces one for voice vlan and another for data vlan

for qos u need at lean the followin g command i nthe uplink to the oruter

mls qos trust dscp

good luck

Community Member

Re: Correct Config for CME connection to Switch

I have set up InterVlan routing on the Switch rather than having sub-interfaces on the Router.

The CME uses (the Switch IP) as its Gateway to access the Data VLAN.

Do I remove "mls qos trust cos" from the Switch interface and replace with "mls qos trust dscp"?

Is the rest of the config OK?

Community Member

Re: Correct Config for CME connection to Switch

Can anyone confirm the above? Thanks, Chris

Re: Correct Config for CME connection to Switch

You should configure 'mls qos trust dcsp' on the switchport connected to the gateway, this will simply replace the 'mls qos trust cos' command on the interface.

If you have spanning-tree configured on your switch, then yes it is recommended to enable spanning-tree portfast on this port. This will ensure that the port does not go through the STP listening/learning cycle when the port comes up.

If you are using Inter-VLAN routing on switch, then the switchport connected to the gateway should be a memeber of the respective voice vlan 20 (If this 192.168.1.x).

The CME router only requires the default route to the Switch SVI if connectivity is required to the Data VLAN as you have mentioned.

Hope this helps.


CreatePlease to create content