[j-nsp] BGP4 MIBv2 question on bgpM2PrefixInPrefixesAccepted (fwd)

[Pekka Savola]

No response on idr IETF list, so..

I think Juniper's implementation/interpretation of accepted/rejected 
prefixes in the brand new BGP MIB is a bit funky, and loses some 
important information (this was tested on 6.1R1).

Is it just me or should PrefixesAccepted include also those prefixes 
which passed through the BGP filters, but are currently inactive due 
to the existence of a route of better preference?

---------- Forwarded message ----------
Date: Thu, 18 Dec 2003 15:02:03 +0200 (EET)
From: Pekka Savola <pekkas at netcore.fi>
To: idr at ietf.org
Subject: BGP4 MIBv2 question on  bgpM2PrefixInPrefixesAccepted

Hi,

(I'm not subscribed so please Cc:)

I've a question on BGP MIBv2 bgpM2PrefixInPrefixesAccepted.

What does "and are eligible to become active in the Loc-Rib" 
(intend to) mean? (see below for a snippet.)

My interpretation is, "the prefix was accepted by possible inbound 
filters, but it may or may not be the active route in Loc-RIB".

This obviously needs clarification as at least one implementation does
not list prefixes which are accepted by BGP prefix/AS-path/etc.
filters as Accepted if it doesn't win the best path decision process
(e.g., if there is a route with better local-pref in your system).

Obviously, this is very bad because the MIB does not offer any means 
to get the count of the "hidden" prefixes, which are accepted by the 
filters but not the best paths, if the above vendor's interpretation 
was true.

(The point of this particular exercise is to get the SNMP access to 
information how well the prefix/AS-path/etc. filters are working 
towards a peer.)

**** cut ******

   bgpM2PrefixInPrefixesAccepted OBJECT-TYPE
        SYNTAX     Gauge32
        MAX-ACCESS read-only
        STATUS     current
        DESCRIPTION
            "The number of prefixes for a peer that are installed
             in the Adj-Ribs-In and are eligible to become active
             in the Loc-Rib."
        ::= { bgpM2PrefixCountersEntry 8 }


    bgpM2PrefixInPrefixesRejected OBJECT-TYPE
        SYNTAX     Gauge32
        MAX-ACCESS read-only
        STATUS     current
        DESCRIPTION
            "The number of prefixes for a peer that are installed
             in the Adj-Ribs-In and are NOT eligible to become active
             in the Loc-Rib."
        ::= { bgpM2PrefixCountersEntry 9 }

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings