QoS Pre-Classify on Cisco IOS

Hello Rene,

I was very happy to find you had a lab on this subject. I went through this myself and everything worked as described, except one area. When I moved the service policy off the FA0/0 interface and put it on the Tunnel 0 interface (and removed the qos pre-qualify from the tunnel), the encapsulated IP header had the CS5 markings, but the outer header did not (as seen below)

Outer:

Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00: Not-ECT (Not ECN-Capable Transport))

Inner:

Differentiated Services Field: 0xa0 (DSCP 0x28: Class Selector 5; ECN: 0x00: Not-ECT (Not ECN-Capable Transport))

If I check the output from show policy-map interface tunnel 0, it shows my “interesting” traffic being identified and marked.

With no service policy applied, if I do the extended ping commands (as you did), then both IP headers are marked with CS5 as expected.

The only deviation I had from your lab was to use a policy-map set command of “set dscp cs5” instead of a police command

R1#sh policy-map
Policy Map PM_ICMP
Class CM_ICMP
set dscp cs5

Odd, huh?