[c-nsp] 7600s, DSCP, ASICs, Bollocks

Tue Nov 17 12:46:54 EST 2015

This email sums up the 7600 very well, particularly the last word in the subject :D

Kind regards,
Sibbi

On 17/11/15 17:41, "cisco-nsp on behalf of James Bensley" <cisco-nsp-bounces at puck.nether.net on behalf of jwbensley at gmail.com> wrote:

>All fixed;
>
>To recap:
>Traffic comes in via transit provider attached to 7600-PE1, label is
>pushed, traffic is label switched over to 7600-PE2, PE2 PoPs label and
>sends IP traffic to customer.
>
>Packets are coming from the transit provider with a DSCP making and
>being sent over to the customer with a DSCP marking. I'm was trying to
>set the incoming packets to DSCP 0 on PE1 first, with a policy-map
>with "set DSCP 0" which didn't work. Then without a policy map the
>port is by default in a state of un-trust as mls qos is enabled
>gobally. Still this didn't work.
>
>By default the 7600/PFC is operating in short pipe mode:
>http://www.cisco.com/c/en/us/td/docs/routers/7600/ios/15S/configuration/guide/7600_15_0s_book/mplsqos.html#pgfId-1405948
>
>Switching to uniform mode work, using the global config command "mls
>mpls qos input uniform-mode".
>
>Now PE1 will set DSCP 0 on the incoming transit packets however, even
>in short pipe mode, if the port is untrusted I would have expected the
>DSCP to be set to 0. It seems in short pipe mode no actions can be
>made against the DSCP/ToS value at ingress only egress.
>
>Cheers,
>James.
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