On the Job

I was working for a company whose building was being gutted for renovations. The IT people told the architect about a problem with one of the planned data connections. One cabling run was going to be 105 meters—a problem, since the Institute of Electrical and Electronics Engineers (IEEE) recommends that cabling runs be limited to 100 meters to prevent problems with a network. The architect was concerned about the IT department’s suggestion that he install an additional wiring closet to shorten the cabling run, given that it would cost another $2,000.

Our new network was going to be a switched Ethernet network, meaning that our connectivity devices would be switches rather than hubs. After some investigation and learning more details of the proposed network, a networking faculty member from a local college and I met with the architect and the director of IT. We explained that the 100-meter cabling limitation is only a problem for older networks that rely on hubs. With a newer switched environment, we might see some slight loss of speed for the end user with a 105-meter cabling run, but it would be fairly small.

We offered two options: We could put a repeater between the switch and the end user to shorten the cabling run, or we could allow the cabling run to go over 100 meters. Using free software available over the Internet, we ran simulations for each scenario to see what sort of loss we had. We determined that, at worst, the user would see about a 5-percent drop in the speed of the network in each case.

The institution decided to go with the longer cabling run. We’ve done some tests on the user’s workstation subsequent to building the network and found that the reduction in throughput is even less than 5 percent. So with some free software and a little knowledge of modern network technology, we were able to save the institution the cost of a $2,000 wiring closet.

Michael Qaissaunee
Brookdale Community College