Hello Everyone,

If you would like to see other blogs on how to setup IP SLAs check out these links.

IP SLA  – ICMP Echo – 2 of 4
IP SLA – TCP Connect – 3 of 4
IP SLA – HTTP – 4 of 4 

I’m going to be putting together a four part series on some common Cisco IP SLA monitor configurations.  Cisco IP SLAs are great ways to get statistics on different types of communications between routers.  They’re relatively simple to set up, and reports can be generated by an SNMP trender.

focus on the Jitter monitor.  You can get a ton of information from the Jitter monitor, starting with latency, Packet Loss, and Jitter.  If the router’s clocks are synchronized you can also get the latencies for each way.  By adding a VoIP codec to the monitor, the router can generate the Mean Opinion Score (MOS), and the Impairment/calculated planning impairment factor (ICPIF) score.

Check out Plixer’s white paper on setting up the Jitter operation.  It will walk you through setting up a Jitter monitor, how to trend the statistics, and generate reports.

If you plan on using the jitter operation to monitor VoIP, pay special attention to make sure that you are using the codec that matches the actual codec being used.

It is also important to have realistic expectations on MOS values pertaining to each codec.  Although Cisco’s scale is 1-5 in their documentation, production environments will not see a 5.  The chart below will help in determining how well your communications are doing.


Cisco VoIP Codec White Paper
Cisco VoIP Codec White Paper

Scrutinizer Netflow Analyzer has a My View page that contains gadgets that can integrate with third party applications.  One of these applications is Denika which can trend the IP SLA statistics.  If you have Scrutinizer and Denika ask us about a custom VoIP gadget to display VoIP IP SLA Statistics.

Check out Part 2 of the IP SLA series.


Steve Cunha author pic


Stephen joined Plixer in 2011. Steve’s efforts over the years have helped many customer gain better Visibility and Network Analytics. With more than 5 years of successful technology consultation, Steve has become a thought leader, focusing on how Scrutinizer can be part of a system incorporating other solutions such as Gigamon, Statseeker, Uptime, InfoBlox and Splunk. Firm believer that most organizations will have a larger SDN implementation and greater leveraging the Cloud in the next few years. Steve resides in Scarborough, ME with his wife and two sons.


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