04-26-2010 09:15 AM - edited 03-06-2019 10:48 AM
is it possible to change mpls exeperimental bit
for traffic that enters a 7600 interface ?
i've tried with "no mls qos mpls trust experimental"
04-26-2010 09:30 AM
I have not done it before, but from my understanding, you would have to do so as part of an MQC-based policy that you would configure and apply to the interface. Again, this is my understanding, not Gospel. Try doing it this way to see if you are successful.
Victor
04-26-2010 09:31 AM
What do you want to change it to?
You can apply an input service policy to match on the MPLS EXP and set it to another MPLS EXP value.
If you want to clear any MPLS EXP value to 0, then simply enable MLS QOS globally and do not trust the port.
Regards
Edison
04-26-2010 10:06 AM
Edison;
I believe he tried not trusting but ran into an issue, thats why I recommended what you did -- setting another policy to change it.
Victor
04-27-2010 12:05 AM
thanks Victor,
i've tried,unsuccessfully, with the following configuration
input interface is WS-X6516-GBIC
ios:122-33.SRD4
policy-map SETEXP
class class-default
set mpls experimental imposition 3
interface GigabitEthernet3/1
switchport
switchport trunk encapsulation dot1q
switchport mode trunk
no mls qos mpls trust experimental
service-policy input SETEXP
end
sh policy-map interface GigabitEthernet3/1
GigabitEthernet3/1
Service-policy input: SETEXP
class-map: class-default (match-any)
Match: any
set mpls experimental 3:
Earl in slot 5 :
5612026684 bytes
30 second offered rate 837104 bps
aggregate-forwarded 5612026684 bytes
04-27-2010 12:24 AM
Hello Pierluigi,
if the input interface is a L2 trunk you may be able to set 802.1p CoS but not MPLS exp.
if you had used that service policy on a layer3 interface with MPLS enabled then you would be able to match packets on MPLS EXP bits and to set MPLS EXP bits
the reason is that on wire the frame will appear as an 802.1Q frame with next protocol MPLS
eth Header | 802.1Q 4 byte tag | MPLS 4 byte tag| IPv4 packet or other upper layer PDU
I would expect to be able to change MPLS EXP on a L3 MPLS enabled interface, not on a L2 802.1Q trunk.
Edit:
I've checked on Config guide it should be possible to match on L2 ports I would try with only the input service policy applied
http://www.cisco.com/en/US/docs/routers/7600/ios/12.2SR/configuration/guide/mplsqos.html#wp1481775
there are also EXP mutation maps but these are not supported on layer2 interfaces.
Hope to help
Giuseppe
04-27-2010 11:52 PM
ok, thank you Giuseppe
since 7600 is able to change dscp even for l2 switched packet, i would expect it could change mpls experimental too,
but i was wrong
pierluigi
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