From: Richard Gallagher (rgallagh@cisco.com)
Date: Wed Aug 17 2005 - 21:23:04 GMT-3
PE2 will receive a packet with just one label (VPN label). And by
default any labels that are imposed will have the EXP bit set to that of
the underlying IP packet.
The following link shows some of the standard methods (diffserv
tunnelling) that you can deploy:
http://www.cisco.com/en/US/tech/tk436/tk428/technologies_tech_note09186a008022ad7e.shtml
HTH, Rich
CCIE 7211
Jongsoo wrote:
> I migt be wrong but
> in your topology, I think PE2 may not receive any MPLS packets nor EXP
> becasue PE1 is ingress as well as penultimate-hop router.
> You may need to configure "explicit null" on PE2 for that direction of
> packet flow.
>
> As far as I know, by deafult, EXP bit is carried over MPLS label like
> DSCP or IP precedence or you can reclassify.
>
> Let me know if I am wrong
>
> Thanks
>
>
> Jongsoo
>
>
> On 8/17/05, Zahid Hassan <zhassan@gmx.net> wrote:
>
>>Dear All,
>>
>>
>>I would be really grateful if someone could suggest or
>>propose any config for implementing QOS for MPLS VPNs.
>>
>>I have the following scenario:
>>
>>CE1 -->PE1-->PE2-->CE2
>>
>>I understand that it is possible to mark and match DSCP and MPLS EXP bits as
>>follows:
>>
>>DSCP (CE1)-->EXP(PE1)--->EXP(PE2)--->DSCP(CE2)
>>
>>I am being able to match DSCP bits from CE on PE and apply whatever policing
>>required.
>>I can also set MPLS EXP bits on PE according to matched DSCP bits from CE.
>>
>>What I have not being able to understand is how my set MPLS EXP bits will be
>>carried to the other PEs ?
>>Will I need to apply any service policy to carry MPLS EXP bits from PE to
>>the other ?
>>
>>
>>Regards,
>>
>>Zahid
>>
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