Subject: [rbridge] loops in trill networks

From: Eric.Gray at marconi.com (Gray, Eric)
Date: Tue, 11 Oct 2005 19:36:58 -0300

I think what Radia is saying is that RBridges do not 
participate (originate or forward) BPDUs.  In addition,
an RBridge that determines it has more than one port in
the same LAN/Broadcast domain does not forward between
those ports.  It does not need to directly participate
in STP to know this and this behavior will prevent loop
behavior.

--
Eric

--> -----Original Message-----
--> From: rbridge-bounces at postel.org 
--> [mailto:rbridge-bounces at postel.org]On
--> Behalf Of Joe Touch
--> Sent: Tuesday, October 11, 2005 5:02 PM
--> To: Developing a hybrid router/bridge.
--> Subject: Re: [rbridge] loops in trill networks
--> 
--> 
--> -----BEGIN PGP SIGNED MESSAGE-----
--> Hash: SHA1
--> 
--> 
--> 
--> Gray, Eric wrote:
--> > Larry,
--> > 
--> > 	You've got the sense of Radia's reply reversed.  It's the
--> > 802.1 bridges that look like a single link to the RBridges.
--> > 
--> > 	This is pretty much how I expected this to work.  A cloud
--> > of 802.1 bridges MUST be completely enclosed in either RBridges
--> > or routers. 
--> 
--> I was expecting that to say "or there will be little or no 
--> benefit from
--> the rbridges" - i.e., topology restrictions can't be 
--> enforced per se if
--> we're expecting plug-and-play.
--> 
--> > Rbridges - like routers - do not forward BPDUs.
--> 
--> Let me propose a question. Let's say an rbridge campus looks like a
--> single giant bridge (humor me).
--> 
--> There are two cases:
--> 
--> 	- the bridge participates in BPDU
--> 
--> 	- the bridge does not participate in BPDU
--> 
--> Is it possible in existing systems to have a bridge that does not
--> participate in BPDU? Wouldn't this end up creating loops?
--> 
--> Joe
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