I've recently been tasked with fixing a connectivity problem in the roof void of a remote area, but it's quite a challenge since the previous network/sysadmin has gone missing. The situation is a total disaster: there are Cat5/6 cables all tangled up, along with a few fiber cables thrown in, and patch panels that are just connected to other patch panels! I'm working with a stack of three "Retro" Cisco C9200 switches, managing eight VLANs and facing the issues of poorly labeled ports. I'm not a network architect, but I need to find a way to untangle and document this mess. Where should I start? Any tips or strategies would be greatly appreciated!
7 Answers
Just a heads up, if there are sticky MAC addresses involved, that could complicate things even more!
If you're going to be on site for a while, start using toners and mapping consistently. Cut out anything that seems messy or unresponsive. Just keep repeating the process until you get it sorted. And no worries, I'm just on vacation, not AWOL. Haha!
What I’ve started doing is mapping out the current patches, setting up Librenms and Oxidised for SNMP data collection, and retrieving MAC addresses to match against DHCP leases. Then I’m planning a cleanup based on what data I've gathered. If things get too overwhelming, it might be best to hire someone who specializes in this kind of work.
First things first, you need to map out all the ports and cables and figure out where they lead. It's going to be tedious, but you have to untangle those cables and re-cable where necessary. Document everything you do as you go along to keep track of the changes.
Before diving into rewiring, audit everything at the patch panels and switches. A network tester can really help here. If you're planning to remove any old cabling, I recommend hiring a structured cabling company to handle it, especially if you'll have to crawl in the roof void—it can be unnerving!
I get it, crawling into tight spaces isn’t everyone’s cup of tea.
Your best bet might be to trace from the farthest point back to the server room. This way, you can start from a known endpoint and hopefully track where everything connects without guessing.
To set a solid foundation, leverage features like DHCP snooping, CDP neighbors, and IP device tracking on your Cisco switches. These can give you a clearer picture of your network environment.
I tried using CDP, but I'm getting a lot of error messages in the logs and not much useful data.
Mapping the cables sounds frustrating, but it's crucial. My main concern is figuring out where everything actually connects since it's all a mystery right now.