Will the switch change the DSCP value in Layer 3 forwarding by default? Thanks!

[Evan_liu]

Switch configured vrrp for hosts, and hosts send traffic with DSCP. By default, when switch forwarding the traffic to network, how the DSCP with tag, the original one or change to 0? Thanks!

[Evan_liu]

Hey Palu

Thanks a lot for the reply. It helps much.

We need to keep the DSCP to the network for end-to-end QoS deployment. If switch will not change the DSCP, then we need not configure any QoS on Switch. 🙂

Thanks

BR/Evan

[Paul_Russo]

Hey Evan

The switch should not change the DSCP by default when forwarding at L3. We can change the DSCP by changing the DSCP value of a queue and re-write it.

One thing to be aware of is that by default .ip has precedence over DSCP in the QoS of a packet. So if a packet is set as .1p value of 0 and a DSCP of 46 and we don't change the precedence of how the switch looks at QoS we will look at the 0 value before we look at the DSCP value.

Hope that helps

P

[Paul_Russo]

Hello the only way to change precedence to have the switch look at DSCP over .10 is to disable .1p or use an acl to look at DSCP and assign it to a queue.

[CodeRed_Red]

How can we change the precedence of how switch look at 0 value before look at DSCP