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I am Val Glinskiy, network engineer specializing in data center networks. TIME magazine selected me as Person of the Year in 2006.

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Tuesday, March 10, 2009

Tracking routing entries on Cisco7600 via SNMP

I have Cisco7604 with SUP720 running c7600rsp72043-ipservicesk9-mz.122-33.SRD.bin. Cisco's SNMP object navigator claims that this image supports RFC1213-MIB which has ipRouteTable. In reality here is what I got

~$ snmpwalk -v2c -c public [myrouter] ipRouteDest
RFC1213-MIB::ipRouteDest = No Such Object available on this agent at this OID


After "Asking" around, I found RFC2096, that states:

The ipForwardTable updates the RFC 1213 ipRouteTable to display multipath IP Routes. This is in turn obsoleted by the ipCidrRouteTable.

The ipCidrRouteTable updates the RFC 1213 ipRouteTable to display multipath IP Routes having the same network number but differing network masks.


ipCidrRouteTable is actually supported by my IOS image, even though Cisco's SNMP object navigator declares it "depricated" and recommends using inetCidrRouteTable (1.3.6.1.2.1.4.24.7)

~$ snmpwalk -v2c -c public [myrouter] inetCidrRouteTable
IP-FORWARD-MIB::inetCidrRouteTable = No Such Object available on this agent at this OID


No luck again, but ipCidrRouteTable (numeric 1.3.6.1.2.1.4.24.4) works just fine.

Here is the list of the objects in ipCidrRouteTable
ipCidrRouteTable 1.3.6.1.2.1.4.24.4
ipCidrRouteEntry 1.3.6.1.2.1.4.24.4.1
ipCidrRouteDest 1.3.6.1.2.1.4.24.4.1.1
ipCidrRouteNextHopAS 1.3.6.1.2.1.4.24.4.1.10
ipCidrRouteMetric1 1.3.6.1.2.1.4.24.4.1.11
ipCidrRouteMetric2 1.3.6.1.2.1.4.24.4.1.12
ipCidrRouteMetric3 1.3.6.1.2.1.4.24.4.1.13
ipCidrRouteMetric4 1.3.6.1.2.1.4.24.4.1.14
ipCidrRouteMetric5 1.3.6.1.2.1.4.24.4.1.15
ipCidrRouteStatus 1.3.6.1.2.1.4.24.4.1.16
ipCidrRouteMask 1.3.6.1.2.1.4.24.4.1.2
ipCidrRouteTos 1.3.6.1.2.1.4.24.4.1.3
ipCidrRouteNextHop 1.3.6.1.2.1.4.24.4.1.4
ipCidrRouteIfIndex 1.3.6.1.2.1.4.24.4.1.5
ipCidrRouteType 1.3.6.1.2.1.4.24.4.1.6
ipCidrRouteProto 1.3.6.1.2.1.4.24.4.1.7
ipCidrRouteAge 1.3.6.1.2.1.4.24.4.1.8
ipCidrRouteInfo 1.3.6.1.2.1.4.24.4.1.9

If you run BGP and accept all routes from the internet, it might be useful to watch the size of your routing table. ipCidrRouteNumber (1.3.6.1.2.1.4.24.3)does just that. If you want to graph it in Cacti use 1.3.6.1.2.1.4.24.3.0 For some reason Cacti needs .0 in the end

1 comment:

  1. This also works for JunOS 9.3.

    ReplyDelete