Go CCIE Go!! - A Cisco Certified Internetwork Expert

Hello,
I just tried a very similar scenario to yours (Uniform mode) with dynamips.
If I turned on “debug mpls packet”on P1 (where the match and rewrite of the EXP occurs) then the policy maps/service policies wouldn’t work. It confused me because I had seen some increment in the counters but that was from the time before I had activated the debug. So it worked properly after turning off this debug and observing further along in the P core such as on your R4 (enabling debug mpls packet here).
Is there some caveat when using “debug mpls packet”?
-Rich

On Mon, Nov 17, 2008 at 11:40 AM, Con Spathas wrote:
> Gday, > > I think I’m missing something quite fundamental here but I can’t seem to > find the reason why… > > I have the following setup: > > R1 (CE) - R2 (PE) - R3 (P) - R4 (P) - R5 (PE) - R6 (CE) > > R2 is matching ICMP inbound from R1 and marking it MPLS EXP 4 > R3 is matching MPLS EXP 4 from R2 and remarking it to MPLS EXP1 > > I see that is happening when I debug on R4 (the COS=4 on the XMIT is the > VPN > label) which is what I expect as R5 is currently sending implicit null to > R4. > If I configure R5 to advertise explicit null in LDP, the debug output > changes correctly and the xmit CoS = 1. Anyhow that’s not my issue - just > background info. > > R4 > *Mar 1 02:40:51.859: MPLS: Et0/0.34: recvd: CoS=1, TTL=253, Label(s)=19/21 > *Mar 1 02:40:51.863: MPLS: Et0/0.45: xmit: CoS=4, TTL=252, Label(s)=21 > > The bit that is eluding my understanding is the output on R3. > > R3 > *Mar 1 00:10:59.075: MPLS: Et0/0.23: recvd: CoS=4, TTL=254, Label(s)=17/21 > *Mar 1 00:10:59.079: MPLS: Et0/0.34: xmit: CoS=4, TTL=253, Label(s)=19/21 > > I can’t work out why the xmit is showing the CoS=4 - even though R4 does > receive it as CoS=1 ? I expected on R3 to see CoS=1 on the XMIT. > > This is the policy map in have inbound on R3’s connection to R2. > > class-map match-all EXP4 > match mpls experimental topmost 4 > ! > policy-map IN > class EXP4 > set mpls experimental topmost 1 > > The policy-map output is incrementing counters correctly. So whilst the > re-marking is working - I don’t quite understand why the debug on R3 isn’t > consistent with what I subsequently see on R4. > > Any insight would be great. Thanks. > > Con. > > > Blogs and organic groups at http://www.ccie.net > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html
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