Tuesday, September 22, 2009
There is widespread confusion about the differences between sFlow and NetFlow and they are often simply referred to collectively as xFlow, implying that the two technologies are interchangeable. The sFlow and NetFlow posting described some of the technical differences between the two technologies, in particular, describing how sFlow operates at the Switch/Ethernet/LAN level and NetFlow operates at the Router/IP/WAN level. This division helps understand where the two technologies fit in the market.
The chart breaks down networking into switching and routing on the x-axis and network speed on the y-axis and then plots the application areas for sFlow and NetFlow. Since sFlow is built into switch ASICs, it offers monitoring solutions that span the full range of layer 2-3 switching products, from inexpensive switches aimed at office and small business environments, to the most demanding applications in supercomputer data centers, Internet exchange points and digital effects render farms. NetFlow is typically found in enterprise class routers. Since performance critical components of NetFlow are often implemented in software, NetFlow isn't widely used for monitoring at the high end of the router market (tier-1 ISPs). The cost of NetFlow enabled equipment limits its use at the low end of the router market.
Dividing the market into routing and switching products and the related applications helps explain why some vendors support sFlow while others support NetFlow. The chart also explains why a vendor might offer sFlow on their switch products and NetFlow on their router products. In practice, most networks blend switching and routing in order to meet the varied requirements of the different services running on the network. In many cases, a network monitoring strategy that embraces both sFlow and NetFlow delivers the most complete visibility into network activity.