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[mpls] New Liaison Statement, "T-MPLS Consented Recommendatio ns"

  • From: Shahram Davari <Shahram_Davari@pmc-sierra.com>
  • Date: Tue, 11 Apr 2006 08:43:01 -0700
  • Cc: mpls@lists.ietf.org, tnadeau@cisco.com



> -----Original Message-----
> From: George Swallow [mailto:swallow@cisco.com]
> Sent: Tuesday, April 11, 2006 11:25 AM
> To: neil.2.harrison@bt.com
> Cc: mpls@lists.ietf.org; tnadeau@cisco.com
> Subject: Re: [mpls] New Liaison Statement, "T-MPLS Consented
> Recommendations" 
> 
> 
> Neil -
> 
> > (i)	I agree with you that some clarity is required on 
> > specific reserved label ranges and their uses.  However, I'd 
> > say it's bigger than just the label ranges and should also 
> > include how all the header fields (ie S, EXP, TTL) are to be 
> 
> Could you enlighten us as to what you are considering here.  Prima
> facia, it would appear that you are diverting further from 
> MPLS than the
> liaised material would indicate....
> 
> > used in T-MPLS (I noted you don't think this 'T-MPLS' name is 
> > good, but I'll stick with it here).  Why?  Well, folks need 
> > to consider the various client/server relationships that 
> > could exist between the various spins of MPLS as-is and 
> > T-MPLS....and especially misconnectivity between them....so 
> > how is this going to be handled?
> 
> We handle such relationships for ATM, SONET, Ethernet without calling
> any of those MPLS.  I see no argument here for including MPLS in the
> name of your transport technology.


But none of them uses MPLS packet format: MPLS label, TTL, EXP, and switch based on
the 20-bit label, and use EXP-bit to identify the CoS/DP, and use TTL for loop detection. MPLS, by Design, consists of two distinct planes: data-plane and control-plane. If the control-plane nails down only one specific path for an LSP, using say RSVP-TE, then there is no ECMP and merging. Additinally since PHP is optional, there is no mandate to support it. So are you saying a technology that uses MPLS data-plane, but its control-plane doesn't support ECMP, merging or PHP is not MPLS?

-Shahram



> 
> ...George
> 
> ==============================================================
> ==========
> George Swallow             Cisco Systems                  
> (978) 936-1398
>                            1414 Massachusetts Avenue
>                            Boxborough, MA 01719
> 
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