Reporting on QoS using NetFlow is a fairly rudimentary report for even the most basic NetFlow reporting tools.  Although the name of this report differs from vendor to vendor, we are all talking about the same 8 bit ToS field of an IP datagram.  Sometimes mistakenly referred to as DSCP, this 1 byte value is used in an effort to help ensure end to end QoS flow for select business applications. Read more »

Michael Patterson
Scrutinizer Product Manager
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With the release of Scrutinizer v7.3, we’ve been advertising the support of a couple of new filters that focus around reporting on NBAR. HURRAY!

But in case you don’t know exactly what NBAR is or why its so very cool, lets take a step back and look at what it does for us:

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SYDNEY, AUSTRALIA: Nortel has saved around $12 million in the last one year as a result of implementing unified communications (UC) in the organization. This often means voice, video and data all done remotely using a typical laptop.

My experience with UC
Two weekends ago I was up at Lake Winnipesaukee in New Hampshire and my cell phone reception was horrible. I needed to call the office and I didn’t want to use the phone in the hotel room to run up my personal charges and go through the hassle of submitting a reimbursement at the office. I experienced UC by launching my soft phone on my PC and making a phone call after checking my email. Read more »

Michael Patterson
Scrutinizer Product Manager
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This is part 3 of a series on the ToS field (i.e. Differentiated Services Field) of IP frames. I’m getting closer to how it relates to NetFlow and sFlow.  Make sure you have already read Part 1 and Part 2 of this blog.

ToS part 3
In this blog I copy largely from RFC 2474, which was written in 1998. I discuss how 6 bits of the 8-bit ToS is now the Differentiated Services Code Point. See the screen capture below from my first blog. This is where we are today however, many of us still refer to this field as ToS (i.e. type of service). Sometimes it is called the Differentiated Services Field (DSF) but, not as often.  Read more »

Michael Patterson
Scrutinizer Product Manager
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I had a customer ask me how HP Procurve’s Class of Service (CoS) for VLANs could be monitored in Scrutinizer with QoS (Quality of Service).

HP Procurves export sFlow (sampled flows). Scrutinizer v6.05 listens to sFlow counters and samples. If specific VLAN tag information is sent out, Scrutinizer ignores it in the current release.

What the sFlow collector (e.g. Scrutinizer), does see is the ToS (Type of Service) byte included in the sFlow packet. The values for this 8-bit field can be defined in Scrutinizer in the QoS Definitions option in Settings. The QoS Definitions feature allows network administrators to customize their QoS settings, with the ability to run reports based on the 8 bit ToS values or 6 bit DSCP values.

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I know that I already blogged about being back from SharkFest 2009. I wanted to write about my favorite keynote speaker, Dr. Lawrence Roberts. He was one of the founders of the Internet and TCP/IP.

Overview of Internet growth
During his presentation he said that 80% of Internet traffic is caused by 5% of the people and most of the traffic created by this 5% is P2P.  He went on to point out that in 2008 22% of the population was online.  By 2018 it will be at 99%.

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Michael Patterson
Scrutinizer Product Manager
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We’ve arrived at the final part of this blog series outlining some of the great Cisco NetFlow analysis improvements that will be found in Scrutinizer 7.0. With features like the ones we’re putting out in this new version, Scrutinizer is easily one of the best values in the flow-analysis market. Let’s continue outlining some more features of Scrutinizer 7.

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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.

Raul J Duran