No Netflow, Catalyst 3750?

Unanswered Question
Feb 14th, 2009

I am currently working on a project that has 30 plus Catalyst 3750G switches in its network solution, the 3750 is a great switch, however one problem the 3750 does not appear to support Netflow!

which is a bit of a problem, will there be a software upgrade in the near future?

Thank you for your time.

I have this problem too.
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Giuseppe Larosa Sat, 02/14/2009 - 23:49

Hello Marcel,

C3750 is a multilayer switch: if in designing its internal architecture support for netflow hasn't been introduced the feature will never be supported:

the way it works or a feature is supported in HW or it is not supported at all.

Even C3750 ME MetroEthernet is not able to support netflow

Netflow is very useful for monitoring traffic and also it can be used for security.

My understanding is that C3750 is not going to support netflow but let's wait to see if some Cisco netpro can confirm this.

Hope to help


Edison Ortiz Sun, 02/15/2009 - 09:04


NetFlow in switches runs on ASICs. In other words, a hardware dedicated for that service needed to be integrated in the switch during its built and requires major chassis/hardware changes.

A software upgrade won't provide this service. It is much easier for Cisco to deploy NetFlow on routers as they are software based devices unlike switches which are hardware based devices.




marcel.felix Sat, 02/28/2009 - 13:10

Thank you for your response,

The Catalyst 4507E appears to be the solution needed.



Edison Ortiz Sat, 02/28/2009 - 13:17


As far as the 4507-E, please be aware of the following:

To use the NetFlow feature, you must have the Supervisor Engine V-10GE (the functionality is embedded in the supervisor engine), or the NetFlow Services Card (WS-F4531) and either a Supervisor Engine IV or a Supervisor Engine V.

NetFlow isn't supported under Sup6-E at all.




marcel.felix Sat, 02/28/2009 - 13:27


Good tip,

In fact i was just review the Cisco data on the supervisor V-10GE module.

I will be using redundant supervisor




dmooreami Mon, 02/16/2009 - 13:02

Back in 2005 or so, the 3750s would actually take the netflow commands, but give no "netflow". It drove me crazy till I called TAC and they confirmed the hardware wasn't there for netflow, but the IOS image did have it. Hope they have fixed that snfu by now.


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