I am looking for an easy way to document a network that has a Cicco Catalyst 3750 with multiple vlans. They had a consultant come in and set this up but I need to better understand how the network is setup. Is there a "visual" diagram somewhere in the web interface of this device that can help with that? Is there a tool from Cisco that can help with this???
As you can see I am not extremely versed in Cisco but I do understand most of the basics of routing and networking. I just need to understand what is connected to what and how it is routed.
If you only have one or 2 switches, you can login to it via cli and use "sh cdp nei" to figure out what port connect to what switch and document it. You can also do a "sh run" and look at the entire config including vlans, subnets, etc... and document them.
As Reza says you can just login and perform various commands, write this down on paper and then put in a diagram form. You can use Visio.
You can also try show vlan or show vlan brief to see the vlans, show int status to see whats connected and whats not etc...
you could try some network discovery tool like this
or try to google some other...
There is also a free Cisco Network Assistant tool available
But to really understand your LAN using CLI commands mentioned by Reza and Sayed and creating a diagram yourself is the best way.