[c-nsp] Using BFD as a link monitoring protocol

[twelcome at mobileemail.vodafonesa.co.za]

Thanks, Oliver. I'll do some test setups on this and let you know the results!

Regards,
Traiano

Sent via my BlackBerry from Vodacom - let your email find you!

-----Original Message-----
From: "Oliver Boehmer (oboehmer)" <oboehmer at cisco.com>
Date: Fri, 27 Nov 2009 10:13:51 
To: <twelcome at mobileemail.vodafonesa.co.za>; <cisco-nsp at puck.nether.net>
Subject: RE: [c-nsp] Using BFD as a link monitoring protocol

 
> Correct, I intend using one of bgp, isis or other appropriate IGP with
BFD
> as cisco recommends in their documentation.

Ok. fine.
 
> Are you sure there is no mib for BFD?, I see, on ciscos ftp mib
repository,
> a bfd-ietf-mib.txt that reads " ... Mib for bidirectional forwarding
> protocol... "?

There is this MIB, but as far as I know, it has just been implemented,
and it is currently ony in 12.2(33)SRE images. No idea when this will
show up in other trains..

> Alternatively, if I used this with isis, for example, would I be able
to
> have isis generate traps, based on detection performed by the BFD
mechanism?

I think so, you can use ciiAdjacencyChange (in CISCO-IETF-ISIS-MIB) to
detect ISIS adjacency changes (MIB support is also quite new, please
check availability in your image(s) using MIB locator at
http://tools.cisco.com/ITDIT/MIBS/MainServlet)
 

	oli

> 
> ------Original Message------
> From: Oliver Boehmer (oboehmer)
> To: twelcome at mobileemail.vodafonesa.co.za
> To: cisco-nsp at puck.nether.net
> Sent: Nov 27, 2009 9:03 AM
> Subject: RE: [c-nsp] Using BFD as a link monitoring protocol
> 
> Hi,
> 
> >  I need to monitor the state of links between router interfaces, and
I
> have
> > a case where the link may go down (due to fibre break at L2) but the
> > interfaces still appear up when polled (we're on a ring). When a
link
> goes
> > down I need to get sent a trap specifically identifying which link
> went
> > down, so I've looked at BFD (Bidirectional Forwarding Detection),
and
> the
> > idea is to set up bfd sessions to run between each pair of
interfaces
> that
> > define a link, and a session failure will result in snmp traps being
> sent
> > identifying which link failed.
> >
> > My question is: Has anyone deployed BFD for this purpose, i.e link
> failure
> > monitoring, and is this an appropriate application of BFD?
> 
> Well, you can't just run BFD by itself, you need to have an
> application/client (routing protocols, HSRP, etc.) which is configured
> to use BFD before BFD establishes a session (not sure if the hidden
> command "bfd neighbor x.x.x.x" can work around this).
> In addition, BFD MIB is not yet there except in 12.2SRE.
> 
> Not sure how many pairs you need to monitor, but you could investigate
> using IP-SLA probes for this purpose..
> 
> 	oli
> 
> 
> Sent via my BlackBerry from Vodacom - let your email find you!