Subject: [rbridge] Comments on: http://www.ietf.org/internet-drafts/draft-ietf-trill-rbridge-arch-01.txt

From: sgai at nuovasystems.com (Silvano Gai)
Date: Wed, 1 Nov 2006 09:22:10 -0800

Eric,

If the sentence "load-splitting among multiple paths", does not mean
Layer 2 ECMP, what does it mean?

How can I split the load among multiple paths, without doing
multipathing?

To split the load, I need at least two paths, If they are not Equal
Cost, what are they?

-- Silvano

> -----Original Message-----
> From: Gray, Eric [mailto:Eric.Gray at marconi.com]
> Sent: Wednesday, November 01, 2006 9:09 AM
> To: Silvano Gai
> Cc: rbridge at postel.org
> Subject: RE: [rbridge] Comments on: http://www.ietf.org/internet-
> drafts/draft-ietf-trill-rbridge-arch-01.txt
> 
> Silvano,
> 
> 	There is a difference.  I've been participating in this working
> group for some time, and I have not heard anyone suggest using L2 ECMP
> is what the charter means by "load-splitting among multiple paths."
> 
> 	However, I agree we need to be fair.  Consequently, let's ask
> other people to weigh in on this issue.  You assert that the charter
> means to include L2 ECMP as an explicit requirement of the TRILL work.
> I assert that it does not.
> 
> 	What do other people say?
> 
> --
> Eric
> 
> --> -----Original Message-----
> --> From: Silvano Gai [mailto:sgai at nuovasystems.com]
> --> Sent: Wednesday, November 01, 2006 11:29 AM
> --> To: Gray, Eric
> --> Cc: rbridge at postel.org
> --> Subject: RE: [rbridge] Comments on:
> --> http://www.ietf.org/internet-drafts/draft-ietf-trill-rbridge
> --> -arch-01.txt
> -->
> --> Eric,
> -->
> --> When I propose something that is not in the charter, it is
> --> out of scope
> --> because not in the charter; when I propose something that is in
the
> --> charter, it is out of scope because "this is not what the charter
is
> --> meant to
> --> describe."
> -->
> --> Let's be fair!
> -->
> --> IMHO, if TRILL does not support Layer 2 ECMP, it is not
> --> interesting at
> --> all for us. All the interest in replacing Spanning Tree is
> --> to get Layer
> --> 2 ECMP.
> -->
> --> -- Silvano
> -->
> --> > -----Original Message-----
> --> > From: Gray, Eric [mailto:Eric.Gray at marconi.com]
> --> > Sent: Wednesday, November 01, 2006 8:20 AM
> --> > To: Silvano Gai
> --> > Cc: rbridge at postel.org
> --> > Subject: RE: [rbridge] Comments on:
http://www.ietf.org/internet-
> --> > drafts/draft-ietf-trill-rbridge-arch-01.txt
> --> >
> --> > Silvano,
> --> >
> --> > 	As I said in my other reply, this is not what the
charter is
> --> meant
> --> > to
> --> > describe.
> --> >
> --> > --
> --> > Eric
> --> >
> --> > --> -----Original Message-----
> --> > --> From: Silvano Gai [mailto:sgai at nuovasystems.com]
> --> > --> Sent: Wednesday, November 01, 2006 1:08 AM
> --> > --> To: Gray, Eric
> --> > --> Cc: rbridge at postel.org
> --> > --> Subject: RE: [rbridge] Comments on:
> --> > --> http://www.ietf.org/internet-drafts/draft-ietf-trill-rbridge
> --> > --> -arch-01.txt
> --> > -->
> --> > -->
> --> > --> Eric,
> --> > -->
> --> > --> The charter says:
> --> > --> "load-splitting among multiple paths"
> --> > --> The pragmatic way to achieve this is to implement Layer 2
ECMP
> --> > -->
> --> > --> -- Silvano
> --> > -->
> --> > -->
> --> > --> > -----Original Message-----
> --> > --> > From: Gray, Eric [mailto:Eric.Gray at marconi.com]
> --> > --> > Sent: Tuesday, October 31, 2006 9:25 AM
> --> > --> > To: Silvano Gai
> --> > --> > Cc: rbridge at postel.org
> --> > --> > Subject: RE: [rbridge] Comments on:
> --> http://www.ietf.org/internet-
> --> > --> > drafts/draft-ietf-trill-rbridge-arch-01.txt
> --> > --> >
> --> > --> > Silvano,
> --> > --> >
> --> > --> > 	See below...
> --> > --> >
> --> > --> > --
> --> > --> > Eric
> --> > --> >
> --> > --> > -- [snip] --
> --> > --> > -->
> --> > --> > --> Sgai 2> I think we should explicitly mention layer 2
> --> > --> multipath.
> --> > --> > -->
> --> > --> > -- [snip] --
> --> > --> > -->
> --> > --> >
> --> > --> > What do you mean by layer 2 multipath?
> --> > --> >
> --> > --> > Do you mean "link bundling" or something else?
> --> > --> >
> --> > --> > Are we trying now to apply ECMP to routing advertisements
> --> > --> for layer
> --> > --> > two reachability?  That's a big step, particularly
> --> when we need
> --> to
> --> > --> > retain compatibility with existing 802.1 bridges.
> --> > --> >
> --> > --> > I don't recall seeing anything about this in the problem
> --> statement
> --> > --> > document, so I don't know of any reason why we should
> --> > --> include it in
> --> > --> > the architecture.
> --> > --> >
> --> > --> > --
> --> > --> > Eric
> --> > -->
> -->