Posts tagged ‘SLAs give me the jitters’

13 April, 2012

Monitoring Cisco IP SLAs: syslog messages

by gorthx

Now that I have an SLA in place, and have some baseline data, I want some notifications in case my SLAs drop. I’ll cover basic syslog messages here, and SNMP traps in another post.

Cisco’s docs have a neat graph that shows how the reaction-config interprets the thresholds. There’s also a handy-dandy chart that tells us which reactions are available for each type of SLA.

I configured a udp-jitter SLA, so everything in the ‘UDP Jitter’ column that’s marked with a Y is something I can configure a reaction for. I’ll check RTT [1], jitter, MOS, and timeout for starters. Initially, I tried this out on just a few routers, with some numbers very close to my collected stats (see last week’s graphs), so I could make sure it was working. Here, I have adjusted them to some more realistic numbers; YMMV.

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30 March, 2012

Monitoring Cisco IP SLAs: rrdtool

by gorthx

Last week I set up an SLA to monitor jitter & looked at the stats available on the command line. This week, I’ll graph those stats.

Like I mentioned, this is quick-and-dirty monitoring, just meant to give me an idea of what I’m working with. This isn’t necessarily something I’d deploy to production, especially since there are products available that already do this. (Which I hope to have time to review in the near future.)

These OIDs from CISCO-RTTMON-MIB look promising:

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23 March, 2012

Configuring Cisco IP SLA for jitter

by gorthx

We’ve been playing around with IP SLAs at work lately (here’s a quick overview of SLAs and what they can do for you). Right now we’re mainly interested in monitoring VOIP services, so we set up an SLA to monitor jitter.

First, we need to configure a responder. This is the machine that will field all of the SLA requests. For our tests, we used a tiny lab router (a stock 2921) – we want to find out how much extra load SLAs would add, so we used something small in order to maximize opportunities for breakage.

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