cos rewriting on switch

Hello all,

I have a question about cos rewriting on a switch. Here is scenario:

R1(f0/0.100)-----dot1q------(f0/1)SW1(f0/2)------access-------(f0/0)R2

On R1 I configured class maps and policy map to identify what cos is
received.
SW1 has NO mls qos enabled or any cos configuration.

When I ping R1 from R2 i see that R1 receives packets marked with cos0. Why
? Packets that leave R2 are not tagged with cos value, why then R1 receives
packets cos0 ?
Is cos0 a synonym of no cos marking ?

Blogs and organic groups at http://www.ccie.net
Received on Tue Nov 09 2010 - 23:31:18 ART