[c-nsp] Monitoring L3 link status

Frank Bulk frnkblk at iname.com
Wed Dec 13 20:34:56 EST 2006


Thanks for checking the BGP4-MIB angle.  I am avoiding the SNMP trap angle
because I believe that SolarWind's Orion doesn't support receiving SNMP
traps.  

Correct me if I'm wrong, but a change in BGP state many not *necessarily*
indicate that the far end router is not accessible, right?

I'm also wondering if something can't be done with IOS scripting/Tcl shell
to check every 30 seconds and then set an SNMP value
(http://tinyurl.com/v6vos) that could be read via SNMP.

Another person recommended using static routes for B to D and C to E, and
then making sure that I have a higher cost route to null for the case when
the interface is down.

Frank 

-----Original Message-----
From: Brad Henshaw [mailto:brad.henshaw at qcn.com.au] 
Sent: Wednesday, December 13, 2006 7:00 PM
To: frnkblk at iname.com; Cisco-NSP Mailing List
Subject: RE: [c-nsp] Monitoring L3 link status

Frank,

According to the 3750ME config guide, the BGP4-MIB isn't supported, but
you could probably setup switches B & C to send traps to your monitoring
box when there's a BGP state change and react on those. This would
depend on support for BGP traps in the IOS version you're running.

Regards,
Brad

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Frank Bulk
Sent: Thursday, 14 December 2006 8:36 AM
To: Cisco-NSP Mailing List
Subject: [c-nsp] Monitoring L3 link status

We're using two Cisco 3750-ME routers (B & C) that are connected to our
upstream service provider's routers (D & E).  We started using ping
checks to D & E from our server running SolarWinds, but because our
internet traffic runs primarily over B-D or C-E it's not really a good
link test.  If our traffic runs over C-E then ping checks to D run over
C, E, and then on to D.  Link B-D could fail and we wouldn't know.

           |---OSPF---[B]---BGP---[W]---[EoS]---[EoS]---[D]
           |           |                     / \         |
server ----A         OSPF                   |   |       BGP
           |           |                     \ /         |
           |---OSPF---[C]---BGP---[X]---[EoS]---[EoS]---[E]

This can't be a new issue -- what's the easiest way to test L3
connectivity between B-D and C-E?  All our connections internally and to
our upstream provider are Ethernet, transport is Ethernet over SONET)
and testing for interface status is not reliable enough as our demarc
with our upstream provider is a Cisco 2950 (W & X).  I believe our
upstream provider uses Juniper routers.

Regards,

Frank



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