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How to map out a switch network manually
Hi,
I have a remote data centre that I'm trying to map out, without visiting the site and tracing cables. Given that I can access the address table on each switch, what's the easiest way to find out if switch A is connected to switch B? the switches in my DC are stacked, which complicates matters slightly.
For example when I look at my MAC address table, almost all of my switches have a single MAC per port, apart the channel port (I believe this is a link aggregate port) which shows MAC addresses belonging to Dell, Cisco and other devices. How do I know where the channel port plugs into directly? Whether it goes to a Dell switch or say a Cisco switch?
Thanks
aetius80
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August 23rd, 2013 05:00
Just in case anyone else needs this, I found out the following tools invaluable:
Use the web browser on each switch to view LLDP nieghbors (gives actual switch ports and can also show the advertised details on non Dell kit)
Use the "show mac" and "show bridge" commands
Show isdp neighbors is also helpful (depends on switch firmware)
Open Network Manager wasn't as intelligent as I was hoping for example, with the SNMP strings to two directly connected switches, I couldn't find a way for ONM to give the actual link ports
Anonymous
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August 14th, 2013 12:00
Without physically being at the switch you may not be able to fully map things out.
Depending on the switch you can run the command
Show bridge address-table
That will show you a list of the ports and the MAC address of the device plugged into the ports.
in the Web interface, at Switching > Address Tables > Dynamic Address Table, you can enter a MAC address and it will tell you what port it's connected to.
Another forum user was able to use the Mac addresses to map out the ports on a 55xx switch. It may be worth looking into to see if you can replicate the method they used.
en.community.dell.com/.../19500445.aspx
"With LanSweeper I was able to scan my switches and the main MAC address of the switch is assigned to the "internal interface" and the VLANS. Starting from port one the MAC addresses assigned to each port increments up IN HEX from there.
So for instance from my example if my main MAC address for my switch was listed as:
d0:67:e5:yy:xx:19 the ports, starting at port 1, would be d0:67:e5:yy:xx:1a, port 2 d0:67:e5:yy:xx:1b, etc.
So....my interconnected ports are 45 and 47 physical ports up from the first port [59H] therefore: (86 hex - 59 hex= 2d hex = 45 dec) and (88 hex - 59 hex= 2f hex = 47dec) [don't forget this is hex not decimal]"
There is also various 3rd party software available that advertises the ability to map ports.
Keep us updated on what you find that works for you.
Anonymous
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August 23rd, 2013 11:00
That is really good information to have. Thank you for sharing this solution with us.