Subject: draft-ietf-l3vpn-mpls-vpn-mib drop counter

From: Ronald Bonica <[email-masked]>
Date: Sun, 23 May 2004 22:46:21 -0400

Folks,

By now, I hope that some of you have reviewed
draft-ietf-l3vpn-mpls-vpn-mib-03. This MIB contains a performance table
entry representing each VRF on a router. Each performance table entry
contains the following objects:

- mplsL3VpnVrfPerfRoutesAdded - "Indicates the number of routes added to
this VPN/VRF since this device has last been reset or the VRF was created,
whichever came last."   
- mplsL3VpnVrfPerfRoutesDeleted - "Indicates the number of routes removed
from this VPN/VRF."   
- mplsL3VpnVrfPerfCurrNumRoutes - "Indicates the number of routes currently
used by this VRF."

It has been proposed that a RoutesDropped counter be added to each
performance table entry. The RoutesDropped object would reflect the number
of routes dropped due to prefix limits since the device was last reset.
Proponents of this counter maintain that it would be useful for planning
purposes.

Others maintain that this counter would be difficult to maintain without
also maintaining a database of discarded prefixes. Otherwise, it would be
impossible to distinguish between two prefixes being discarded and the same
prefix being discarded twice. Also, this counter would never decrement. It
would only reset when the SNMP agent resets.

I would like those who have an opinion on way or another to please speak up
on the list. We will defer last call on this document for one week to allow
this discussion. If there is no discussion in one week, we will progress the
MIB to last call without this counter.

----------------
Ronald P. Bonica
----------------

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From: Thomas Nadeau <[email-masked]>
Date: Mon, 24 May 2004 10:20:52 -0400

> would only reset when the SNMP agent resets.
	
	One additional point you missed was that this counter
doesn't indicate which protocol tried to add the offending route/routes,
so it makes it further difficult to use in practice.  Given this plus
the other reasons you list above, I have a hard time understanding its
usefulness.

	--Tom