Trust COS or DSCP on trunk links?

Unanswered Question
Nov 3rd, 2009
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Old QOS SRND states for trunk links, you must trust the COS. However we have offices were they has trust DSCP on trunk links, and dscp values are carried through.

Is it now possible and should we be trusting DSCP instead of COS on trunk links? If not, how would the dscp values be carried through if trust cos is not set on trunk link (but trust dscp value is)?


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KonradStepniewski Tue, 11/03/2009 - 08:22
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Phone will mark with CoS 5 voice traffic then on switch do cos-to-dscp mapping to correct value and on trunks you can trust dscp.

show mls qos maps (command my be different on deffierent platforms) will show you current mapping


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