[c-nsp] MRTG on SONET APS?

Lamar Owen lowen at pari.edu
Tue May 12 09:11:35 EDT 2009

On Friday 08 May 2009 05:25:31 pm Pete Templin wrote:
> I'm in the process of bringing up my first SONET APS-protected
> (single-router APS) link, and it's been an adventure. 

Is this a true 'single-router' APS setup, or is it a 'multirouter' APS setup 
that just happens to be on a single router?  (There is a difference in the 
configuration).  I have an APS protected OC3 here, and am tracking with MRTG on 
the far end, which has two routers.

> Unfortunately, MRTG is only seeing 16bps on one port, and 0bps on the
> others.  Is there something special to tracking the traffic on an APS pair?

Unless MRTG can do additive interfaces (that is, have an RRD that records the 
sum of the working and protect interfaces' counters) you will have two RRDs, 
one for the protect and one for the working.  I think the behavior is also 
platform-specific; but as I don't have MRTG monitoring the near end router pair 
at the moment, I don't know.  Hmm, I think I should enable that and see if 
that is the case.

While I currently have the near end working on a 12012, and the protect on an 
OSR7609, I do know that 'one-router multirouter' APS will work on the 12012, 
so , for grins and giggles I can set up that and do a little testing (after 
notifying my OC3 providers, of course, as they'll get LOS alarms when I move 
the plug over....).

One minor note, for completeness: I'm assuming you're not monitoring the 
loopback, but monitoring the individual POS interfaces, right?  (Like I said, 
I assume you are monitoring the POS interfaces, but, just in case....)

Welcome to the mad world of SONET APS.  I've had this circuit up for two 
years; wouldn't be quite so 'interesting' if it were a single provider 
circuit.  However, APS does 'neat' things when you hand off one provider to 
another, and they're using disparate vendors' ADM's.  Both providers have been 
very good to work with, and lots of knowledge has been gained by all parties 
in the process, though!

Also, for completeness, do you mind sharing the configs for the two POS 
interfaces, and the results of running the combination of:
debug aps
show aps
no debug aps

(sanitized of IP addresses and aps authentication information, of course)

Turning APS debugging on causes show aps to give more detailed information.

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