Subject: [rbridge] Ingress Rbridge and FTAG again

From: sanjays at cisco.com (Sanjay Sane (sanjays))
Date: Thu, 26 Oct 2006 14:38:49 -0700

I think you're suggesting adding one (outer) .1Q Tag, apart from
customer's original (inner).1Q tag (the real VLAN tag), and use the
outer .1Q as the index to the forwarding table for purposes of Ftag. 

Issues with this approach could be combining this concept with TRILL.
For e.g. would such a .1Q tag come before TRILL's existing shim header
or after ? Where would original .1Q tag (original VLAN) fit in?
Potentially, forwarding decision may need to take all 3 ethertype's into
account. 
Also .1Q payload portion is 16 bits (12 bits vlan, 3 bit pri, 1 bit
CFI). If we really need the Ftag functionality (from the outer .1Q tag),
10 bits (as proposed in the new shim header) should be enough. 

The new shim header (proposed as per
http://www.ietf.org/internet-drafts/draft-gai-perlman-trill-encap-00.txt
) takes all of this into account and packs them into the TRILL context. 

-Sanjay

-----Original Message-----
From: rbridge-bounces at postel.org [mailto:rbridge-bounces at postel.org] On
Behalf Of Maltbie, Dan
Sent: Wednesday, October 25, 2006 11:07 PM
To: rbridge at postel.org
Subject: Re: [rbridge] Ingress Rbridge and FTAG again

The IEEE 802.1Q VLAN TAG should do everything an rbridge could possibly
want to do with an FTAG and it will be much more interoperable with
existing and future Ethernet equipment. There's already a standard way
to push/pop VLAN tags. Other standards, like provider bridging, are
taking advantage of Ethernet's excellent flexibility. Why re-invent the
wheel?

just a thought...

Dan Maltbie
Woven Systems, Inc.

-----Original Message-----
Message: 5
Date: Wed, 25 Oct 2006 19:30:26 -0700
From: "Sanjay Sane \(sanjays\)" <sanjays at cisco.com>
Subject: Re: [rbridge] Ingress Rbridge and FTAG again
To: "Radia Perlman" <Radia.Perlman at sun.com>
Cc: rbridge at postel.org
Message-ID:
	
<7178B7E237F45D45BE404AFF0AF58D870181BCCF at xmb-sjc-213.amer.cisco.com>
Content-Type: text/plain;	charset="us-ascii"

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