cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
664
Views
0
Helpful
1
Replies

DSCP tags are set to zero by 3750 after routing between VLANs

samytehrani
Level 1
Level 1

Hi All,

I have a 3750 switch with the following configuration on access ports:

switchport access vlan 1
switchport mode access
switchport voice vlan 2
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape  10  0  0  0
mls qos trust cos
auto qos voip cisco-phone
spanning-tree portfast

There are two voice vlans defined on this switch. I have two Cisco IP phones connected to access ports. If I put these access ports in the same voice VLAN and capture the traffic, I can see that incoming and outgoing traffics have EF DSCP tags on them. If I put these access port in different voice vlans and capture the traffic at each, incoming RTP traffic will lose the DSCP EF tag and DSCP will be set to zero, however the outgoing traffic will still have the  EF dscp value.

1 Reply 1

Scott Bradley
Cisco Employee
Cisco Employee

Hi

I am not clear what you mean by setting traffic flow to full.  Can you elaborate on that a bit?

Thanks

Scott

Getting Started

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: