LAN Congestion issue

[qbakies11]

I believe I may have a LAN bottleneck/congestion issue but I'm not sure exactly how to find it. I want to use a sniffer but I don't know if it will do any good with my current configuration.

I have 5 Catalyst 3548 switches in a stacked configuration that everything on my LAN connects into. In order to catch traffic with a sniffer or bandwidth monitor I am going to have to set up a SPAN port, correct?

Do I need to set up a SPAN port on each switch? Does SPAN have a big effect on traffic flowing through the switch? If I set up a SPAN port on each switch would I have to connect my sniffer to each individual SPAN port to monitor the bandwidth on that switch?

Thanks in advance for any help.

[daniel.bowen]

Hi There,

What would be more simple is to create a SPAN VLAN, and then catch all traffic on the VLANs you wish to capture, then have that forwarded onto the SPAN VLAN. You then place your sniffer into the SPAN VLAN you have created.

See the following link for a better explanation to what I have provided 8-)

http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_37_se/configuration/guide/swspan.html#wp1200730

Dan