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

From: manoj.k.wadekar at intel.com (Wadekar, Manoj K)
Date: Wed, 1 Nov 2006 10:03:14 -0800

For Data Center networks, increasing bisectional bandwidth is very
important and "load splitting between multiple paths" is important to
achieve this. L2 ECMP is logical way of doing it. This is how I read as
well.

What is the alternative? I think multiple trees rooted at each node and
using shortest path to the destination is a limited approach as compared
to L2 ECMP.

Thanks,
- Manoj

-----Original Message-----
From: rbridge-bounces at postel.org [mailto:rbridge-bounces at postel.org] On
Behalf Of Gray, Eric
Sent: Wednesday, November 01, 2006 9:32 AM
To: Silvano Gai
Cc: rbridge at postel.org
Subject: Re: [rbridge] Comments
on:http://www.ietf.org/internet-drafts/dr
aft-ietf-trill-rbridge-arch-01.txt

Silvano,

	Let's leave-off restating our cases, and simply let others 
comment on what they think is meant by this phrase in the charter.

--
Eric

--> -----Original Message-----
--> From: Silvano Gai [mailto:sgai at nuovasystems.com] 
--> Sent: Wednesday, November 01, 2006 12:22 PM
--> 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,
--> 
--> 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
--> > --> > -->
--> > -->
--> 
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