CCNA Level, Common Problems

[ChaosInMind]

This is a bit out of the norm, but I think this could become a fantastic resource of real world experience.

Please, just follow along and throw in your twenty-five cents worth.

Everyone, listen up. In your own words. In YOUR hands on experience, what are the most common problems that you encounter with routing and switching, LAN or WAN.

I don't care what the textbooks say. Please tell the world what you feel are common encounters and what you do to resolve them.

I'll start!

Hello, I am a entry level network tech in the Cisco world but have dealt with SOHO networking for years. What I've noticed as a common problem in LAN/WAN is the misuse of bridges, repeaters, unauthorized equipment and cabling. For some reason techs extend wires way too far and when it malfunctions they implement a sideways fix like plugging a Linksys router into a drop the next office over, and fishing the cable over the duct work as it hags from the ceiling in office.

I also notice poor cabling techniques in data closets. You should see the mess here! What I do to resolve these issues is lead by example. While I'm in the field working with a tech I make it a priority to go out of my way to do it the right way, fix a mess little by little. Bring a cable tester for example and ask the tech what they think of the 345 meter result and what we should do to fix the low signal. Being the bigger tech and leading by example will indeed develop a better team over time.

Now its your turn!

[ibrunello]

The two biggest issues I always find quite difficult are:

- managing and troubleshooting (in zero-time, of course) big routing issues that involve ISDN backup and route redistribution on multiple star topology: carefully study standard metrics, and program a crash test during off-peak, to ensure everything is running.

- troubleshooting STP (and the dreaded "STP storm" when running 802.1d STP, with all network down for 50 secs, is something everybody don't want to experience in his/her network): use rapid-STP (easy, fast, reliable), or DON'T USE STP AT ALL (e.g. use Cisco "FlexLinks", or etherchannel).

These are the most common ones I've been facing, and still face.

Recently I managed to setup a new datacenter: NEVER FORGET TO LABEL ALL CABLES (and use a common labeling method/software), expecially on the ditribution switch closet.

Suggestion: use a Database where you use "circuit" to identify end-to-end connection, and "cables" to identify patches. Each cable has a parent circuit; a cicuit is made up of one or more cables (see inter-closet connection).