Network Mapping Tips and Tricks

Posted in NetFlow, NetFlow Analyzer, Network Traffic Analysis on March 23rd, 2011 by Dalel
Network Mapping Tips and Tricks

A network administrator needs the type of centralization of network information that our NetFlow analyzer maps offer. These maps are a high level view of a network that keeps the admin informed of not only device locations and current statuses, but also provides quick access to traffic information. In addition, links on the maps change color based on definable thresholds and display the utilization. This is a valuable tool, especially for very large networks. In this blog I would like to share a trick I recently learned  about adding multiple links between two devices.

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Scrutinizer Class Map Reporting

Posted in General, Network Traffic Analysis, Scrutinizer, Voice Over IP Stress Test on February 16th, 2009 by Steve
Scrutinizer Class Map Reporting

There is no question that our Network monitoring tools are our eyes into how our network is being utilized.  Moreover, to truly gauge the efficiency of changes made to the network to increase efficiency, it’s critical to have performance trends before and after changes are made.

Scrutinizer QoS reporting can be the key to troubleshooting or evaluating network performance of traffic going through QoS queues.

Today we’ll talk about how we can use Scrutinizer’s custom reporting to analyze the traffic associated with QoS and class maps.

We know that to create a class map, we can specify the DSCP value we want to be included in the class map.  In the map below we can see that EF in the name column corresponds to a codepoint of 10111000, for example.

Scrutinizer allows class map reporting by simply adding the Diffserv codepoints assigned to the DSCP Values of your class map to your custom report.  It’s just like as if you were creating a class map, except instead of the DSCP Value you use the codepoint.

Let’s say we have a router with a VoIP class map configured to include the EF DSCP Value.  Let’s also say we want to analyze traffic associated with this class map on this specific router.

All I need to do now is to create a custom report in Scrutinizer where I have included the 10111000 (EF) Codepoint, select interfaces belonging to this router, and I’m instantly viewing a report of all the traffic flowing through my VoIP class map.

We can also use this same technique to create a custom report on a class map that hasn’t been rolled out yet, so that you can verify that the changes made to the router configuration have resulted in the changes intended in traffic flow.

Ideally, the administrator would pair this with a Cisco IP SLA Jitter monitor that would also give stats on:

• Latencies including source to destination, destination to source, and jitter.
• MOS Score if the class map affects VoIP Traffic
• Packet Loss metrics including late, or out of sequence packets, and tail drop.

By comparing the before and after statistics, verification can be made of increased efficiency and everybody is happy.

If you would like information on how to setup the Cisco Jitter IP SLA, check out the 4 part Cisco IP SLA Blogs on Systrax.



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