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3750 and Netflow not supported (alternatives ??)

              ISP

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|             3750            |  --------  |           3745              |

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          Internal

I have an ISP facing 3750 switch running BGP. I want to collect Netflow statistics for this IP traffic.

I know that Netflow is not supported on the 3750 switch.

I know Lancope offer a Flow sensor for capturing data on a span port and turning this into netflow stats.

http://netflowninjas.typepad.com/blog/2009/12/stealthwatch-510-highlight-flowsensor-ae-features-and-benefits.html

I need a temporary solution and I have a spare 3745 router which supports netflow. I cant put this router

in series because it may be a bottleneck on a 20Mbps ISP connection.

Is there a way of feeding span traffic from the 3750 into a 3745 and seeing if it is able to generate the netflow stats.

I have tried this using only one interface and it does not work. Do I need to span both internal and external interfaces.

Does the IP traffic arriving at the 3745 have to cross two interfaces to generate neflow stats.

http://www.netflowanalysis.com/How%20does%20NetFlow%20Work.html

Any ideas ?

1 REPLY
Bronze

Re: 3750 and Netflow not supported (alternatives ??)

Hello,

there are only 3 solutions.

1. Small router inline. I suppose that it will OK for 20Mbps line.

2. Use SPAN and some probe (software or hardware based).

3. Optical TAP and probe.

Our company is offering software or hardware based probes.

(see http://www.caligare.com/product/flowmon/ for more information)

You can also use the Lancope or nProbe (free) of course.

Kind regards,

Jan Nejman

Caligare, co.

http://www.caligare.com/

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