Friday, May 15, 2009

Network-wide visibility

One of the unique features of sFlow is its ability to monitor entire networks, not just selected devices or links. When configuring sFlow monitoring, enable sFlow on every switch port on every switch in your network. sFlow is implemented in hardware so it can operate at line rate without impacting switch performance.

Don't just monitor WAN links and core switches, enabling sFlow on access switches gives detailed visibility into every server in the data center and every PC on the campus without the need to install software agents on the servers and PCs.

The scalability of sFlow extends to the traffic analyzer software. A single, well designed, sFlow analyzer should be able to monitor all the switch ports in the network. When choosing a traffic analyzer, count the total switch ports in your network and select software that will be able to monitor all the ports. A modest size campus network may have 20,000 switch ports and a large corporate network may have in excess of 100,000 switch ports. It is a good idea to request an evaluation and perform a full scale test to verify that the software delivers the required scalability.


  1. Peter, this is great info in today's DC designs specially (post is 3 years old now :)) but with speeds and feeds going to 10/40G pushing to 100G, sampling & monitoring strategy of this sort is great.

    What are the main advantages & disadvantages you see with a similar DC design with Netflow turned on on the network elements?