How to monitor bandwidth (without netflow)

[Josh Rountree]

I've got a 3850 switch, and an 1800 router with a switch module in it.

All of our WAN connectivity is Metro-E, so we have the interfaces configured on our switches and use the routing in the switches to connect each site. Is there any way to monitor bandwidth from the switch? Something is killing our WAN connectivity but I can't find it. I guess I could move those interfaces to a router, but that would require a re-design?

[Leo Laohoo]

Netflow is probably the best but if this is not an option then the more archaic method of "ip accounting" is another option.  

If "ip accounting" is not an option, go to SolarWinds' Network Performance Monitor.

[milan.kulik]

Hi,

IMHO, the best way would be configuring NetFlow on the 3850 switch.

Even without a collector (and no exporter configured on the switch so) you could check and sort the flow cache contenet and find the top talkers.

Here you can see how to configure Flexible NetFlow on 3850 switches:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/37e/flexible_netflow/configuration_guide/b_fnf_37e_3850_cg/b_fnf_32se_3850_cg_chapter_010.html#task_1C8520F2E2F243E6B7B9F2C4C144B27C

and here how to look into the flow cache to find the top-talkers:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/fnetflow/configuration/15-mt/fnf-15-mt-book/cgf-topn.html#GUID-07FBA0E0-B66E-4839-9DBD-7C30CB67C386

Best regards,

Milan