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Will this Cat-6509 honor QOS DSCP packet markings?

I have an older 6509 with Sup-1A running IOS 12.1(20(E2 and CatOS 7.6(3a) and will not be able to upgrade the code. QOS is not turned on at all on this box. Unfortunately this 6509 is in the middle of a network where I need to pass VoIP traffic. At both ends of the network I have newer 3750 switches with my PBX plugged in via IP at one end and I have several IP phones at the other end of the network.

The PBX and Avaya IP phones mark the correct DSCP values, but when the packets traverse through the old 6509 the DSCP/COS bits are set to all zeros.

With the version of OS and CatOS that is running on the older 6509 can I enable QOS and will the DSCP bits be left alone as the VoIP packets travel through the switch?


Re: Will this Cat-6509 honor QOS DSCP packet markings?


Do you have QOS enabled right now ? If you have it enabled and port trust states are not set, then cos and dscp values will be zeroed out. Do a sh qos status . It will tell u if qos is currently enabled or not.

If not the correct procedure would be

a. globally enable qos (set qos enable)

b. Set port trust states (trust cos/dscp/prec). Some linecards only allow u to trust cos values.

c. Set a COS to DSCP mapping, which is required to generate a internal DSCP value (internal use in the switch).

d. Set any policing if required

e. Set any egress queueing settings

f. Create a qos acl and specify which traffic should get qos.



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