RE: decisions on L2 solutions documents

Giles,
> > > 
> > > Wouldn't it be kind of cool if we could use the same 
> > > addressing format for 
> > > what ever MPLS LSP/pseudo wire/tunnel? Is it too simple to 
> > > say we always 
> > > identify the end-point of an LSP/PW/tunnel with a unique 
> > > address (I mean 
> > > unique for the LSP/PW/tunnel so no 2 PWs share the same address)? 
> > > 
> > But it that case how about pw created for l2vpns.
> > NH=> Hamid why do you think you need PWs at all?  The only 
> reasons PWs exist
> > is as follows:
> > -	to fix the problems caused by mp2p LSPs.....if you want any-any
> > connectivity use a cnls mode, in a co pkt-sw mode only p2p and p2mp
> > constructions make any arch sense....mp2p leads to problems 
> and kludges;
> > -	to keep the pretence-up that MPLS =~ IP.....if true why 
> do we need
> > MPLS then?  Use the right mode for the right application....both are
> > required;
> > -	to squeeze a bit of the server-layer BW via client 
> compression (a
> > total non-issue IMO when other technolgies squander BW).
> [rest snipped] 
> 
> Meanwhile, back in the real world, PWs (in the MPLS context) do the
> following:
> 
> 1) add a label to the stack to keep state out of the core 
> (this may also
> create a p2p LSP on top of an mp2p LSP, depending on whether you are
> using LDP or RSVP-TE for your tunnel LSPs).
NH=> This is an LSP issue and belongs to the proper MPLS layer
network....nothing to do with PWs.

> 2) create a bidirectional p2p construct out of two unidirectional p2p
> LSPs.
NH=> This is an LSP issue and belongs to the proper MPLS layer
network....nothing to do with PWs.
 
> 3) adapt the layer 2 protocol being carried to MPLS.
NH=> Now you have it....PW are about adaptation....with that I agree.

> This involves
> three things:
> i.   stripping off the layer 2 header (aka "compression") in the cases
> such as FR where the header may be different at each end.
NH=> Yep, bit of BW squeezing

> ii.  sequence numbering, if required, for the case where the core
> network may reorder packets.
NH=> Yep, there to fix lower layer MPLS problems.

> iii. length checking, for the case where the core network's 
> minimum PDU
> is larger than that of the PW (this is required because MPLS has no
> length field).
NH=>Agreed, adaptation function should pad to minimum.
> 
> Giles 
>  
> -- 
> =================================================================
> Giles Heron    Principal Network Architect    PacketExchange Ltd.
> ph: +44 7880 506185              "if you build it they will yawn"
> =================================================================
> 
>