Subject: RE: [Idr] draft-ck-bgp-atm-nlri-01.txt to become a working group document?

From: "Busschbach, Peter B (Peter)" <[email-masked]>
Date: Mon, 13 Dec 2004 08:50:10 -0500

Pekka Savola wrote:
> On Mon, 13 Dec 2004, Busschbach, Peter B (Peter) wrote:
>> I object against the use of the word "ATM hack". The draft
>> represents a straightforward application of Multi-Protocol
>> extensions for BGP. Draft-ietf-idr-rfc2858bis-06.txt says: "This
>> document defines extensions to BGP-4 to enable it to carry routing
>> information for multiple Network Layer protocols". Now that we
>> propose to use this to carry ATM routing information, it is suddenly
>> a hack??
> 
> Depends on what you call 'Network layer', I guess :). Network layer
> typically refers to the layer of "IP". 

It is not the first time that I notice that IETF members use the word "multi-service" when in fact they are only interested in IP. It always reminds me of the American habit to call the winner of a national sports championship the "world champion" :-)

ATM is both a link layer and a network layer protocol. ATM uses routing protocols that are very similar to IP routing protocols. The main difference between IP and ATM is that IP is connectionless and ATM is connection-oriented.

> From the perspective of IP,
> ATM routing information is at the link-layer.  This would seem the
> similar to propagating Ethernet MAC addresses of VPLSs (for example)
> in NLRIs.

Yes, it would be similar, if Ethernet would use routing protocols to advertise MAC addresses. However, Ethernet uses learning bridges in a loop-free topology and is in that respect different from both IP and ATM.

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From: Curtis Villamizar <[email-masked]>
Date: Mon, 13 Dec 2004 12:43:05 -0500

In message <[email-masked]>
"Busschbach, Peter B (Peter)" writes:
> It is not the first time that I notice that IETF members use the word
> "multi-service" when in fact they are only interested in IP. It always
> reminds me of the American habit to call the winner of a national
> sports championship the "world champion" :-)
>  
> ATM is both a link layer and a network layer protocol. ATM uses
> routing protocols that are very similar to IP routing protocols. The
> main difference between IP and ATM is that IP is connectionless and
> ATM is connection-oriented.
>  
> Yes, it would be similar, if Ethernet would use routing protocols to
> advertise MAC addresses. However, Ethernet uses learning bridges in a
> loop-free topology and is in that respect different from both IP and
> ATM.

We heard that ATM would dominate the world in 1993 and end-user TCP
would just have to learn to work over ATM.  We heard that all IP would
run over ATM in the mid-1990s.  None of this came from IP providers,
mostly from ATM vendors with some sort of credibility attached to it
through statements passed through the ATM Forum.

I haven't seen a single message from a provider supporting this.  I
don't think I've seen a single message from a non-author supporting
this as a WG item.

Yes, in principal PNNI is like an IP IGP and BGP could be its exterior
routing protocol.  ATM itself is end-to-end connection oriented and
ATM SVC service has never been offerred by any major provider so
arguments of scaling due to not having an exterior routing protocol
completely fall apart.

It is not unreasonable for an IETF WG to demand strong indication that
there is a clear requirement for anything that the WG is asked to
consider as a WG work item.  We've asked and there has been no
indication from any provider of any need for this.

Curtis