In-line monitoring vs. NetFlow or sFlow

Plixer CEO Mike Patterson gives his take on the Net Optics - Jimmy Ray Purser video.

Michael Patterson - CEO of network performance vendor Plixer International provided all of the following blog information below in regard to the Jimmy Ray Purser video about Net Optics: ---------------------------------------------------------------------------------------------------------------------------------- Hi Brad, I watched the demo. I like Jimmy Ray Purser and follow him on Twitter. In-line monitoring and link aggregation is a good business. Definitely a need for this in the IT field. I like Netflow as I don’t have to buy any hardware and because it's free on Cisco routers (keep in mind that I'm also biased because the product I make, Scrutinizer - is a network management tool that uses Cisco NetFlow, sFlow, Juniper J-Flow, IPFIX or NetStream to provide historical trends of traffic data across all critical network interfaces). Collecting and analyzing NetFlow and sFlow is a very cost effective solution. Placing probes in a dozen or so places on the network is expensive to purchase and maintain. Most of the time the level of detail gained form NetFlow reporting is sufficient and packet capture only needs to be done in a few key locations. We are not saying replace packet analyzers entirely, we suggest augmenting them with more flow analysis. Which is better, in-line monitoring or NetFlow? Like all loaded questions, it depends. What are you looking to capture? In-line Monitoring A - Inexpensive

1. Pass the uplink through a hub (not a switch) and then plug the packet capture device into the hub. 2. Setup port spanning (i.e. mirroring) of the uplink of the switch to another interface so that the packet capture device can see the traffic.

B - Investment (avoiding the word ‘expensive’)

1. Place an in-line appliance to capture/forward the traffic onto multiple destinations.

With hardware from vendors such as NetOptics, traffic can be duplicated out to multiple ports. Network Instruments and other vendors provide similar solutions. View the solution brief: Net Optics and Cisco NAM Net Optics Tap technology can also add value to the Cisco NAM solution by providing aggregation, regeneration, switching, media conversion, and filtering capabilities:

Enjoy the video below of Network World Cisco Subnet blogger Jimmy Ray Purser getting the lowdown about in-line monitoring from Net Optics:

NetFlow or sFlow Monitoring If the goal is to gain insight into who or what is hogging bandwidth, enabling a flow technology on your switches or routers and forwarding the data to a collector/analyzer is a great alternative, however, you don’t get all the packet details. A - NetFlow

NetFlow aggregates the data and basically gives you summarized information such as IP addresses, ports, protocol, total bytes and packet volume plus a whole bunch of other fields.

B - sFlow

sFlow provides the entire packet but, it is only sampling and it may not sample the packet you need.

Both are generally free and standards based (NetFlow = IPFIX). In short there is a market for both, depending on what you need to do.


What's your take on in-line monitoring vs. NetFlow or sFlow? BradReese.Com Cisco Refurbished - Services that protect, maintain and optimize Cisco hardware Contact: Brad Reese | Twitter: http://twitter.com/BradReese

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