3650, 3850 switch port configuration for avaya phones

[gavin han]

Hi,

Could someone advise what switch port config to be put on for avaya phone connection to 3650, 3850 switches? how to trust dscp from avaya phones?

[Mark Malone]

Hi

so ios-xe 38s/36s trusts incoming dscp by default if the Avaya phone is marking it , do you know if the phones mark at the source with EF 46 like Cisco ? if not span the port quick it should show you in pcap if there marking them most phones do now

Use this command to see the dscp counters

sh platform qos dscp-cos counters gigabitEthernet x/x/x

Ingress DSCP45 0             0
Ingress DSCP46 564718942     0

Igf its marking at source you don't need to do anything for voice , you can test again with pcap make sure markings still carried leaving the switch ,or other option is use auto qos , ios-xe doesn't support mls

[gavin han]

Thanks Mark. what will be the switchport config where avaya phone connects? would it be following?

int gi1/0/1

 switchport

 switchport mode access

 switchport access vlan 10

 switchport voice vlan 11

 switchport priority extend trust

[Mark Malone]

You need to be careful how you set the extend trust command especially if the phone is marking the packets already as the port is set by default to trust dscp , so it will honor and carry it, if the phones are marking already I would leave that off , and I'm not sure if it will work as well as it uses cdp which is Cisco proprietary and there Avaya phones

For best practice as well add In spanning-tree portfast and spanning-tree bpduguard for any phones and pcs/printers under their interface

switchport priority extend

To configure the switch to override the priority of frames arriving on the Cisco IP phone port from connected devices, use the switchport priority extende command. To return the port to its default setting, use the no form of this command.

switchport priority extend { cos cos-value | trust }

no switchport priority extend

Syntax Description

cos	Specifies that the switch will send CDP packets to instruct the Cisco IP phone to mark data traffic with class of service (CoS) value.
cos-value	CoS value. The range is from 0 to 7.
trust	Specifies that the switch will send CDP packets to instruct the Cisco IP phone to trust tagged data traffic.

[gavin han]

great. Thx Mark.