Need to map and document an un-mapped network

[madbeader]

Good morning,

I have been assigned the task of mapping and documenting our network, unfortunately there is no existing documentation or mapping....big surprise.
In any case we currently have 10 3750G's situated in 3 locations within our plant.  Each group is interconnected with fibre, and the PC's and printers are all regular gig-ethernet, a total of 156.  There is no redundancy between the switches and all 156 PC's are on VLAN 1, totally flat topology.
None of the switchports are labeled, and the switch racks and cabinets are quite disorganized.

If I could get some suggestions as to where to begin unraveling and documenting this I would be ever so appreciative.  I will have Telnet access to the switches and CDP is running.  As you may imagine I'm a little overwhelmed and not exactly what the first step should be.  I should also add that I will be unable to implement any VLANs at this time, as that has to have corporate approval...we'll save that for another day.

Thanks in advance for any thoughts or advice on how to begin.

[Robert R]

Hey Howard,

There's a free tool available from solarwinds that I've used with vairous degrees of success.  From the sounds of your scenario, this may workout quite well.  If you enable SNMP on the 3750s you'll get even more information for your documentation.  IOS, ports, vlans, etc...  Enabling SNMP is easy enough and you can find tons of examples online.

It's called Network Topolgy Mapper

http://www.solarwinds.com/downloads/

It will ask you to register before downloading, and they will email you to follow up, but otherwise it is free.

Good luck and hope it helps.

Thanks,

Rob

[barweiss45]

A NMS like SolarWinds, which has some sort of auto discovery would be an excellent place to start and is something you will most likely want to implement on your network to maintain and operate it too. In the short term you can, use a program that is free which is called Nmap (http://nmap.org/), which is a port scanner. The tool can be used for many reasons as it is pretty versitile, but in your case a general tcp scan of your network would give you an idea of what devices are on your network and how to go about accessesing them.

However, ultimately there is no program that is going to replace the down and dirty of tracing out the physical connections via the CLI. Remember, "Show mac address-table", "Show ip arp", and "show cdp neighbor detail" are going to be your best friends.

[madbeader]

Thanks guys for the input on where to start.  I just need to break this down into little bites otherwise it's just gets overwhelming.  I always knew that the CLI was going to be where the real info was going to ultimately be.

Thanks again.

[schaef350]

If you will not be implementing a more complicated topology for a bit I would just get a physical mapping for now with show CDP neighbors like this.  Us visio to doc it out then and build up incrementally from there as the network grows. 

I typically don't bother with edge ports for hosts/printers but would try to document ports servers connect to with a show mac address table command or even the mac traceroute tool on the Cisco devices link this.

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