[118442] in North American Network Operators' Group

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Re: Consistent asymetric latency on monitoring?

daemon@ATHENA.MIT.EDU (Mikael Abrahamsson)
Thu Oct 22 01:52:09 2009

Date: Thu, 22 Oct 2009 07:51:00 +0200 (CEST)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: Rick Ernst <nanog@shreddedmail.com>
In-Reply-To: <d066472f0910210807k2e921ebck3aef5720170a2ecb@mail.gmail.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org

On Wed, 21 Oct 2009, Rick Ernst wrote:

> Has anybody seen this type of behavior? We are solidly convinced that we 
> are using the proper OIDs and making the proper transformations of the 
> data. The two remaining causes appear to be either "natural behavior of 
> the links" and/or "artifact in the IP SLA mechanism".

I've been using IP SLA for years (right now under 12.4) and I have not 
seen behaviour that mirrors what you see. I often see one-way latency go 
up without the other way doing so.

You should start by looking in "show ip sla (monitor) op" and see what 
values you see in the router, that might give you more information 
regarding where the problem might be (your polling system or if the IP SLA 
agent is actually reporting what you see).

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se


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