Cisco Router Traffic Statistics 1

[leedsit]

Hi,

I have a need at times of busy traffic to jump onto the router and check for a source of high amounts of traffic. Is there an easy way on a cisco router to view this???

Cheers, Lee

LEEroy
MCNE6,CCNP,CWNA,CCSA,Project+

 

[ADB100]

Netflow is probably your best option since this reports bandwidth usage by source/destination IP addresses, protocol utilisation etc. You will however need an application that the router sends the statistics to so it can graph the results etc.

I have been using AdventNet's ManageEngine NetFlow Analyser 5:

http://manageengine.adventnet.com/products/netflow/index.html

It is easy to setup and gives you examples of how to configure your routers. You can download the application for free and it will run unrestricted for 30-days.

HTH

Andy

 

[leedsit]

Thanks ADB100

does the router need special software from cisco?

LEEroy
MCNE6,CCNP,CWNA,CCSA,Project+

 

[ADB100]

does the router need special software from cisco?

No, the only thing you need to configure is flow switching on the router interfaces and a destination to export the statistics to. You need to enable flow switching on each interface traffic will enter and leave for the statistics to work properly. For example if you had a router with an Ethernet interface to your LAN and a Serial interface to your ISP you would configure the following:

interface Ethernet0
ip flow ingress
ip flow egress
ip route-cache flow
!
interface Serial0
ip flow ingress
ip flow egress
ip route-cache flow
!
ip flow-export source Ethernet0
ip flow-export version 5
ip flow-export destination 10.10.10.10 9876
!

The host 10.10.10.10 should be configured with a NetFlow receiving application listening on UDP port 9876. The router in reality holds very little stats since it is the applications job to gather the stats and generate reports etc.

Flow switching is only supported on routers and higher end Switching platforms (Catalyst 4500 Supervisors with NFFC and 6500's). The lower end catalysts don't support this (3550, 3560, 3750 etc).
There is often discussions as to whether flow switching decreases performance of the router since it looks like CEF is disabled, but it works in conjunction with CEF switching on most platforms.

HTH

Andy

 

[leedsit]

Thanks ADB100,

Its a 7200 series running CEF on both interfaces so It looks like I`ll be ok, I`ll just add the commands you mentioned above and download the 30 day tried.... If its good, we`ll make a purchase ( certainly looks good )

Thanks again, Lee.


LEEroy
MCNE6,CCNP,CWNA,CCSA,Project+

 

[ADB100]

You need Perl installed as well, but this is free:

http://www.activestate.com/Products/Download/Download.plex?id=ActivePerl

Once this is installed you simply install NetFlow Analyser and you are away.

HTH

Andy

 

[PalmTest]

NTop can function as a Netflow probe.
You can find a good version at:

http://www.openxtra.co.uk/products/ntop-xtra.php

HTH.