The Dreaded Comms Cabinet

[discoveranother]

Hi Guys & Girls,

 

I'm sure like me sometimes you have to encounter the dreaded network cabinet with several switches in it and several patch panels amongst other things the router, wireless controllers, UPS you name it. Not my favourite, especially when you don't know the place, or what goes where, you are cramped for room and cannot fathom at all where cables are running from and to between equipment.

 

So my question is, in such a scenario when a client has lost complete connectivity to the network or Internet or both what is the best approach. Ok, I will check the server and router are working as they should, check switches are all powered up, but what if all these seem fine. Yes I do all my normal ping tests. But when you have a cab that is described as above and so little time to really start unplugging hundreds of cables and you are rebooting equipment or shutting it down which isn't labelled, anyone have a best approach on this ? If I don't know the place i'm up against it from the off. I've seen switches that visually look like they are working and aren't. Id' rather leave cabinets with many, many switches and hundreds of cables to those who enjoy it !!! Any best approaches to this much appreciated.

 

Thanks

[fredbayker]

You could get a contractor in to do it for you

[geezersoft]

Start at the Internet router and work your way into the network.

[discoveranother]

You could get a contractor in to do it for you

 

Did wonder about that one !

[mukz]

If nothing is working on ANY machine

 

A) Trace the cable going from router, firewall (or web filter) into switch- unless they have some fancy setup this is your internet cable.

B) plug it into your laptop or pc and set the settings to what was provided from client or internet provider - if there is no internet, call internet service provider

C) If internet is working, plug a console cable into the switch which the internet uplink was connected to and see if you get an ip address. See if the dhcp server is responding using wireshark.

 

Thats maybe something along the lines i would go down. There are many ways of doing it.

[discoveranother]

Start at the Internet router and work your way into the network.

 

Yes thank you. The pressure really gets on when you only have a couple of hours and so many switches and hundreds of cables !!!

[geezersoft]

When the system is down, just work the problem. It will be up when it is up.

[Mr.Ben]

lldp and cdp are both your friends here if you have decent switches!.

[Accura2k7]

check the BB routers...

plug a laptop directly to a switch that goes to said router.

ping servers from client?

ping printers around the building?

eventually you should see a pattern.

turn all switches off except router and first switch, make sure you can talk to the world.

turn next switches on and plug laptop in to that one, do the same tests and so on and so on.

[jthompson]

Perhaps identify the uplinks between key bits of equipment and label them at both ends (links between switches, WAPs into switches, switch to router, etc.). Make a note of which ports those key patch leads are plugged into, so that if they get unplugged, you can be sure that they're going back in exactly as they were.

 

It also means that if you run into similar problems down the road, you're not having to work out those important connections all over again, you can just concentrate on the client's connection into a switch. It's also worth labelling up the power leads, so that if you need to power off a particular device again, you'll know which plug to pull.

 

If it's a wired client that's not getting a connection, try it in a known good wall socket if possible, then test its patch lead with a cable tester, the link from the wall socket to the patch panel (hopefully both numbered up), then identify the patch lead in the cab (however long that may take) and test that, then patch a laptop directly into the switch port it was using and check connectivity.

[discoveranother]

Great advice guys. Many thanks.

[eddyc]

In the past I’ve used a sharpie to label the rj45 plugs with the port numbers when I’ve need to unplug say a whole switches worth of connections and am not familiar with what’s connected or where it needs to go back

[elsiegee40]

In the past I’ve used a sharpie to label the rj45 plugs with the port numbers when I’ve need to unplug say a whole switches worth of connections and am not familiar with what’s connected or where it needs to go back

 

I use masking tape to tag cables and write on the tape

[AlanD]

...I'd want to know if anyone and been meddling either before - or after things went wrong. Nothing worse than "have a go jo" moving a few cables around before you get there...because that might make me change my strategy..and be more inclined to disconnect everything..and reconnect things once I knew they were working...Sometimes it can be an errant switch or even PC somewhere else more remote from the cabinet. We had a PC that somehow was managing to take out a whole building until it was turned off.

[southhamster]

I'm a big fan of coloured patch cables eg yellow for uplinks, orange for Poe APs, green for printers etc. Love our Brother labeller as well.

[garygeek]

Never ever believe the I.T bod when they say it was all working and they haven't touched anything!

[njc235]

Whilst they are more expensive, Patchsee cables can be a godsend, even if they're only employed for critical links.

[Wubbalubbadub]

I'm a big fan of coloured patch cables eg yellow for uplinks, orange for Poe APs, green for printers etc. Love our Brother labeller as well.

 

Me too! I thought i was the only one!

 

Black for POE Devices - Probably need to split this, as it current coveres my phones and access points!

Blue for printing

Red for Links / Servers

Orange for Redundent Links

White for End Client

[mavhc]

And a key for what colour means what printed out and taped to the inside of the door, along with your phone number

 

Black between switches, blue for voip phones, orange for wifi, grey for everything else