You work at an 11-building site in which new buildings have been added over time. The buildings share a wired network that began in the late 1990s. Each building is on its own network node, and each node connects to the main network switch via buried coaxial cable.

Over the summer, occupants in three of the buildings often complained about bandwidth limits. One of the other buildings lost network connectivity entirely, and that problem was fixed by laying a new cable (the old one was abandoned in place). This same scenario took place last summer. Your COO does not feel three is a charm; he is talking more along the lines of "three strikes and you're out."

What should you test and what should you propose so that next summer is different?

The fact this is happening in the summer indicates that soil movement due to heating and/or drying out may be stressing the cables. It's likely the failed cables had been spliced. Buildings were added over time, and one solution for quick rerouting is to splice in an extension. Splicing is also a quick solution for repairing a cable that was inadvertently cut during construction.

Some first steps to solving your problem include:

  • Examine the routing of the cables that link the buildings. Do these run under vehicular and/or foot traffic?
  • Using a time domain reflectometer (TDR), test the abandoned cables to see if they have splices. After in-place TDR testing, remove the cables for visual inspection.
  • Use the TDR to check existing cables for splices. Replace any spliced cables.
  • Consider redesigning your links between the buildings. Wireless is an option, but be sure any proposed system will work in all weather conditions. You may want to replace coaxial with fiber-optic cabling run in protective raceway.
  • Review the specs on your network switch. The low bandwidth issue may have nothing to do with the cables, and everything to do with an outdated switch.