Gigabit Ethernet
mitch @ 8:33 am on April 3, 2008
I don’t talk about work much on my blog, mostly because I don’t feel like it is appropriate. However, there are things that I learn while at work that would be appropriate to write about. The purpose of this post is just such a situation. I currently work as a network system consultant and I’ve been doing work onsite for a company for the last 8 months or so. They move large files around, (they’re a printing company) and have also put in a huge investment into gigabit ethernet equipment everywhere. However, most of their buildings are fairly old, and the last time they were cabled was around 1998. Most things are run with your standard Category 5 cable (not even Cat5e). Now the sharp person will know immediately that Cat5 is not supposed to run gigabit. Someone forgot to tell everyone else here, because they put the swithes in place and put gigabit ethernet on the desktops as well… and they negotiated at 1 gigabit…. so it should work right? Wrong! Gigabit ethernet is *very* sensitive to the type of cable being run over it, so much so, that technically you can run it over Cat5e, but if your really shooting for gigabit to the desktop, I wouldn’t go less than Cat6 and making sure you do not run the cable closer than 3 feet from florescent light blasts, and keep it the same distance from all power runs as well. We had a situation in one of the buildings, that they’ve been fighting speed issues for months/years, and in no way did they think it was possible to get faster speeds out of Cat5 cable if I were to drop their speeds to 100Mbit full duplex. Instead of the 1Gbit it was currently negotiating at. Finally we got the ok to force everyone in the building down to 100 Full (actually the switches are HP Procurves, and they have an option to set ports to auto-100 which allows the port to negotiate between full and half duplex and speeds of 10 or 100Mbit, essentially leaving out the option for gigabit). And sure enough speed times increased 3 fold. Imagine that.
Technologyยท Work —
