Re: Use of atmV.lCrossConnectIdentifier for PVCs/SVCs
Peter Jones <peter@atmospherenet.com> Thu, 26 March 1998 04:37 UTC
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Date: Thu, 26 Mar 1998 10:50:46 +0800
From: Peter Jones <peter@atmospherenet.com>
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Organization: Atmosphere Networks
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To: Gary Hanson <gary@kentrox.com>
CC: Mickey Spiegel <mspiegel@cisco.com>, Kaj Tesink <kaj@cc.bellcore.com>, atommib@thumper.bellcore.com, John Neil <jn@aus.atmospherenet.com>
Subject: Re: Use of atmV.lCrossConnectIdentifier for PVCs/SVCs
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Hi Gary, Gary Hanson wrote: > > Mickey, Kaj, (and other atommib-ers), > > I have been trying to dig through the atommib WG archives to find > the final consensus on how the atmVplCrossConnectIdentifier and > the atmVclCrossConnectIdentifier objects should be used to refer to > the various PVC- and SVC-related cross-connect tables. Since the > current internet-drafts are essentially silent on this point, I > thought I would throw the question open to other implementors on > the mailing list to see what they had done (or intended to do). > > To refresh people memories, the following table entries are all > defined to be partially indexed by a cross-connect index in the > range 0..2147483647): > - From ATM-MIB: > - atmVpCrossConnectEntry (1st INDEX: atmVpCrossConnectIndex) > - atmVcCrossConnectEntry (1st INDEX: atmVcCrossConnectIndex) > - From ATM2-MIB: > - atmSvcVpCrossConnectEntry (1st INDEX: atmSvcVpCrossConnectIndex) > - atmSvcVcCrossConnectEntry (1st INDEX: atmSvcVcCrossConnectIndex) > > The cross-connect index values used as INDEXes into these tables > are all apparently derived from the following objects from ATM-MIB: > - atmVplCrossConnectIdentifier (from atmVplEntry) > - atmVclCrossConnectIdentifier (from atmVclEntry) > > As far as I can tell, neither the ATM-MIB draft nor the ATM2-MIB > draft clarify how the atmV.lCrossConnectIdentifier objects from > the atmV.lEntry rows are to be used to identify the ATM2-MIB's > atmSvcV.CrossConnectEntry rows. In fact, the ATM-MIB draft simply > says that these objects only identify the atmV.CrossConnectEntry > rows in the ATM-MIB. > > Was it the intention of the WG that a particular cross-connect > identifier value be used to identify a row in one table or the > other, but NEVER both? For example, if an atmVpCrossConnectEntry > exists with atmVpCrossConnectIndex X, should the agent take pains > to ensure that no atmSvcVpCrossConnectEntry also exists with > atmSvcVpCrossConnectIndex X, and vice versa? This would make > sense to me, but as the documents do not explicitly say this, I > was left somewhat unsure. > > I assume that the WG has abandoned the idea of splitting the > cross-connect identifier values into two disjoint ranges, since > there had been a lot of negative discussion about that, and since > the tables do in fact now share the same indexing range. So am I > correct in assuming that the tables share the same range of index > values, but NEVER share entries indexed by the same cross-connect > index value? > > If so, what does the WG think about adding explicit documentation > to this effect in both documents. The ATM-MIB document deserves > to have this mentioned, since that is where the cross-connect > identifier is defined, and the ATM2-MIB document also deserves to > have this mentioned, since there is otherwise no explicit mention > of where the values for atmSvcV.CrossConnectIndex come from. I > am sure other implementors will come along with the same confusion > as myself. > > Regards, > Gary >From our point of view, both the SVC's and the PVC's share a common pool for cross connect indexes. This is particularly critical which you consider the case of a soft PVC at the edge switch. In this case (according to our interpretation) one link of the connecton is a PVC link which is then cross connected to an SVC link. I guess this does beg the question as to why we need two lots of cross connect tables? regards peter -- ______________________________________________________________________ Peter Jones Atmosphere Networks Manager of Software Development 4th Floor, Balcroft Building Garden Office Park 345 Harborne Street Osborne Park WA 6017, Australia Direct: +61 (8) 9443 0105 Main: +61 (8) 9443 0100 Fax: +61 (8) 9443 6610 mailto:peter@atmospherenet.com http://www.atmospherenet.com _______________________________________________________________________