Troubleshooting Over Utilisation on Network

[buzzhani1]

I have a cisco 1941 router connected to a switch, and a modem. I suddenly noticed a huge slow down with the internet connection. It happened very abruptly. I did an isolated test and noticed i was getting the usual bandwidth from the ISP but when connected to the LAN, the connection slows down drastically. It is crawling. I suspect over utilisation from the LAN, maybe from a user but how do i check where the traffic is coming from? Please any ideas on how to troubleshoot this? Is there a way to check the bandwidth consumed by each client connected to the network?

Thanks.

[ronpestler1]

Hi buzzhani1,

when you need only the meta informations you can configure your 1941 to send flows to a collector.
Or when you dont need history you can view that information (Src / Dst / Port and so on) also
via cli.

flow exporter flow-exporter
 description Export
 destination <IP from collector> <Port>
 source <Interface from which you can reach the collector>
 template data timeout 60
 
flow monitor flow-monitor
 record netflow-original
! Or use this
! record netflow ipv4 original-input
 exporter flow-exporter
 cache timeout active 60
 
interface <lan-interface>
 ip flow monitor flow-monitor input
 ip flow monitor flow-monitor output

Check
show flow monitor flow-monitor statistics

Caution the flow generation need cpu utilization!

As collector you can use different Software (IsarFlow or from Solarwinds, Manageengine and so on)

Best regards