12-05-2013 01:49 PM - edited 03-07-2019 04:57 PM
Hi,
I've just added the following commands to my 6509 switch -
mls qos
interface GigabitEthernet3/24
description *** DATA VLAN 35 - VOICE VLAN 34 ***
switchport
switchport trunk native vlan 33
switchport trunk allowed vlan 32,33
switchport mode trunk
mls qos trust dscp
no cdp enable
spanning-tree portfast trunk
!
I have a phone connected to this port and when I make calls the wireshark output (sniffing on same VLAN) show the markings as being present (e.g. DSCP = 46)
The upstream router (a Cisco 3845) has the following configuration:
!
class-map match-all IPVoice-Priority
match ip dscp ef
!
!
policy-map WAN_QoS
class IPVoice-Priority
priority 30000
class class-default
fair-queue
!
interface FastEthernet2/1
service-policy output WAN_QoS
when I make a VoIP call (that I know is traversing the WAN link connected to fa2/1) and run the command
show policy-map interface fastEthernet 2/0
The packet count isn't incrementing i.e. the traffic is not being identified and prioritised. (I believe the DSCP markings are being set back to zero by the switch before the traffic leaves for the router)
The interesting thing is that if i remove the mls qos configuration from the 6509 switch the markings are left in tact and are making it to the upstream router and onwards on the WAN link.
My theory is that the switch is resetting the CoS or DSCP values before sending the traffic onwards to the router.
Can anybody tell me where I am going wrong? i.e. how can I get the switch to trust CoS/DSCP markings as they leave the local VLAN on the 6509 switch?
12-18-2013 06:38 AM
Hi again Jon.
Yes - the CoS value on the phone is 5 and the phone I believe also set the DSCP value to 46.
Cheers,
Andy
12-18-2013 06:44 AM
Jon. Although I've not got to the bottom of this yet your help on this has been invaluable. I feel i've got a much better grip on this now and once the change freeze is over I'm feeling far more clear about how to continue trouble shooting. I'll update the discussion once I can progress with this.
If you have any thoughts on my earlier responses that would be good to hear.
Thank you,
Andy
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: