RE: [PWE3] New PWE3 Charter Items: SPVC Interworking

[neil.2.harrison at bt.com]

Mustapha,
> Mustapha Aissaoui wrote 24 February 2004 20:00
 
> Scott and Richard,
> both the ATM Forum and IETF should be interested in this 
> work. There are
> hopefully enough experts of both ATM and IP/MPLS who attend 
> the PWE3 working
> group to have this work done here. I do not think it is worth 
> debating which
> body should own it as long as there is a liaison and 
> communication between
> the two bodies. If the IESG decides that this is out of scope 
> of the IETF,
> then we should take it to the ATM Forum.
NH=> I think its bigger than this.  We want to see a stronger respect for the functional architecture principles of G.805/809.  There are many reasons we want this, but a key one is that these func arch models form the bedrock of the network management information models for our NMS/OSS.  So its quite important to us.

Further, we believe that generic arch principles for client/server i/w (aka network i/w) and peer-partition i/w (aka service i/w) should be defined 1st irrespective of the specific technologies involved.  The arch principles are not the same in these 2 i/w cases.  Further, these relationships are affected by (i) the networking mode of the technology considered, ie whether cl-ps, co-ps, or co-cs, and (ii) how well a given technology is functionally specified.

Just taking the simpler client/server case for now, this is what we believe must hold here:
(i)	client and server layers must be independent in all aspects of the data and control planes.  This is required since the client and server layer networks can be owned by different parties.
(ii)	the client (all aspects) must be transparent to the server layer.  Some folks also refer to this as 'the principle of minimum intervention'. 
(iii)	defects detected at the trail termination point of the server layer network must be mapped to a FDI (Forward Defect Indication), in whatever syntax is relevent to the client, at the server->client adaptation function and for all clients affected.  This is to inform client that the defect is not in their layer network and thus stops alarm storms in clients.

We don't believe the current PWE3 drafts on client/server relationships meet the above requirements.....I can provide an extensive list of stuff we feel is wrong here, and we have raised these issues on the lists in the past but they have been ignored.

The original driver for the PWE3 work was from SPs who did not have native ATM, FR, etc technology networks but who, nevertheless, wanted to offer their carriage as services to customers over either an IP or MPLS server layer network.  Well, that's OK I guess, but when it gets a bit more serious such that MPLS (not PWs please note) is being touted as the convergence technology for most SPs (inc BT) then (i) we want to make sure MPLS is correctly/adequately functionally specified and (ii) that the X/MPLS i/w relationships are correctly specified.

In particular, we don't think any single SDO should try and claim 'ownership' of this topic.  And as noted, we want to start from a basis of respecting G.805/809 func arch principles.

regards, Neil

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