Egress Marking of DSCP

[pnschurr]

Hi All,

On a 4500 I can set the internal-DSCP of ingress packets such that a particular egress Q is used on the way out. This process does NOT then result in the internal-DSCP value being written into the DSCP field of IP traffic. Correct?

Does the same apply to 6500/PFC.

thanks

peter schurr

[ace-cco]

Hi Peter,

when you write "internal-DSCP" - what are you referring to? You should be able to mark frames entering specific ports with TOS or DSCP values, which are the used by any configured or default egress queue. This woul result in a new value in the DSCP field.

Or is this "internal-DSCP" a new feature I have not heard of yet?

Regards

Robert

[pnschurr]

internal-DSCP is the tag used by the switch to carry QOS-treatment information from ingress to egress ports. It is pure Cisco proprietory, and is not written to the packet or frame (unless instructed to do so via policy map).

peter

[mark.edwards]

Hi Peter, you are correct. Marking is done at ingress. Packets are queued but not altered at Egress.