Cisco Performance Routing (PfR) and NetFlow
PfR was well defined by Samuel Yee: “For most medium-to-large networks, you would usually have more than 1 ISP to connect the enterprise network to all the remote sites. Traditional routing (such as OSPF, BGP etc) could route network traffic through a preferred path or load-balance among different paths. It can also automatically change path when a link is dead. For many companies however, this still isn’t good enough.

Traditional routing alone can’t detect and take actions on links that are ‘half-dead’ e.g. congested, flappy link etc. To overcome it, Cisco introduces Performance Routing (PfR).”  Samuel Yee – Network Infrastructure Lead

Samuel is trying to point out that routing protocols are not aware of things such as brownouts which can lead to poor network performance. Most companies could benefit from insight on the frequency of these soft errors that impact service levels.  The Cisco Wiki also has a good PfR Overview.

Cisco Wiki on PfR NetFlow
Cisco Performance Routing (PfR) enhances routing in order to select the best path based on user defined policy. The PfR policy can: minimize cost efficiently distribute traffic load and/or select the optimum performing path for applications.

PfR enables intelligent traffic management that can dynamically route around soft errors in the Enterprise WAN or Internet and makes adaptive routing adjustments based on advanced criteria such as response time, packet loss, jitter, mean opinion score (MOS), availability, traffic load, and cost policies.

Cisco PfR augments traditional routing (BGP, EIGRP, OSPF, PBR) with realtime performance metrics in IOS instrumentation (Interfaces, Netflow, IP SLA, …).

What does all the above mean to NetFlow?  New reports of course! PfR uses IP SLA data to report on whether or not traffic on a link is in or out of policy. You can expect reports on Round Trip Time, Packet loss, Jitter, MOS (Mean Opinion Score), etc. As you can imagine, these new Cisco Performance Routing NetFlow exports provide details that are very different from traditional NetFlow reporting.

NetFlow and Performance Routing (PfR)

The above is just the beginning and the benefits include the ability to witness the behavior of PfR changes and how they impact network performance. This takes network traffic monitoring with NetFlow to a whole new level.

You can watch traffic in realtime as it goes in and out of policy and historically trend the results. Optimizing video traffic is one of the targeted uses of this new technology. Together with Cisco WAAS, application optimization can become easier to achieve.  Hopefully someday we’ll see support for PfR in the Cisco ASA NetFlow exports as well.


Mike Patterson author pic


Michael is one of the Co-founders and the former product manager for Scrutinizer. He enjoys many outdoor winter sports and often takes videos when he is snowmobiling, ice fishing or sledding with his kids. Cold weather and lots of snow make the best winters as far as he is concerned. Prior to starting Somix and Plixer, Mike worked in technical support at Cabletron Systems, acquired his Novell CNE and then moved to the training department for a few years. While in training he finished his Masters in Computer Information Systems from Southern New Hampshire University and then left technical training to pursue a new skill set in Professional Services. In 1998 he left the 'Tron' to start Somix which later became Plixer.


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