Re: dot1dStpPortPathCost32

Use of the 32-bit path cost was defined in both 802.1w (RSTP) and 802.1t.
802.1t was a collection of enhacements to Bridges, including those that support
legacy STP.  So the 32-bit path costs do not just apply to RSTP.

I think you are right that dot1dStpPortPathCost32 should be conditionally
mandatory, but for any Spanning Tree implementation that supports 32-bit path
costs, not just for RSTP.

Implementations that support 32-bit path costs should not use the 16-bit path
cost object, dot1dStpPortPathCost, but I am not sure what is the best way to
deal with this.  Are we allowed to allocate a special value to indicate it is
not in use?  I think it would be safer to return an SNMP error indicating the
old object is not supported.

Les...





Juergen Schoenwaelder <[email protected]>@ietf.org on 22/10/2004
12:05:23

Please respond to [email protected]

Sent by:  [email protected]


To:   [email protected]
cc:
Subject:  [Bridge-mib] dot1dStpPortPathCost32


The revised BRIDGE-MIB adds dot1dStpPortPathCost32 and makes it
mandatory. I think this is broken since existing deployed
implementations won't support that object and thus are not
compliant. Can someone please explain in which situations the
increased range of dot1dStpPortPathCost32 is actually needed?
Is this only relevant for rapid spanning tree? In that case,
I think the object should be conditionally mandatory for boxes
that do rapid spanning tree and the old one stays current,
probably with a special value to use in case dot1dStpPortPathCost32
actually has the larger path cost.

Please give advise.

/js

--
Juergen Schoenwaelder             International University Bremen
<http://www.eecs.iu-bremen.de/>        P.O. Box 750 561, 28725 Bremen, Germany

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