Subject: Re: MPLS PID

From: Luca Martini <[email-masked]>
Date: Tue, 01 Apr 2003 14:31:46 -0700

Shahram Davari wrote:
> I agree with Lloyd. Sniffing IP packets in the middle of an MPLS network is fundamentally wrong, and is impossible to do for all ECMP implementations such as the one that I described
> in earlier emails in which both the first nibble and the CRC are used to detect IP.
> 
Shahram,
It might be fundamentally wrong but this is deployed today , and we run our 
hole network based on this little point. It seems to work fine for a network 
that transport 90gb/s to 100Gb/s of actual traffic.

So if we put the theory, and layer arguments aside , what is the issue with 
determining that a particular flow is not IP ( assuming IP = 99% of traffic ) ?

Luca

It might be fundamentally wrong

> The best way to solve this problem is to do ECMP only based on label stack. Doing so should be
> easier than introducing new standard.
> 
> -Shahram
> 
> 
> 
>>-----Original Message-----
>>From: Lloyd Wood [mailto:[email-masked]]
>>Sent: Sunday, March 30, 2003 6:11 PM
>>To: Eric Rosen
>>Cc: [email-masked]; David Allan; 'Scott W Brim';
>>[email-masked]; [email-masked]
>>Subject: Re: [PWE3] MPLS PID 
>>
>>
>>On Thu, 27 Mar 2003, Eric Rosen wrote:
>>
>>
>>>1. The  only  reason for  a  PID  field in  MPLS  and/or  
>>
>>PWE3  is to  allow
>>
>>>   intermediate routers to determine whether a particular 
>>
>>MPLS payload is an
>>
>>>   IP packet or not.
>>
>>which is a layer violation, and shouldn't be done.
>>
>>
>>>   There are a number  of reasons why this is useful, and  
>>
>>no one has argued
>>
>>>   that this is not useful.
>>
>>not appropriate, more like.
>>
>>if you're going to sniff for an IP packet (so you can sniff TCP/UDP or
>>higher) you might want to ask why you even have any form of mpls
>>label stack in there in the first place.
>>
>>if you're not separating out your ip flows via explicit mpls label,
>>why not?
>>
>>L.
>>
>><http://www.ee.surrey.ac.uk/Personal/L.Wood/><[email-masked]>
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> 
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