Networking / Beginners

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Understanding circuit failure issues

The larger the problem, the easier it is to find. If your circuit is completely down and alarms are sounding on your hardware, the bad news is that you may have a large problem, but the good news is that finding its source is pretty easy.

Most dedicated circuits are only about 4 or 5 miles long and have a handful of hardware interfaces in them from end to end. If any single piece of hardware or cabling that handles your circuit fails, your circuit will fail along with it. You know your circuit is in failure when

• Your multiplexer and/or CSU have active alarms. This can include flashing red lights where there used to be solid green lights, and/or an annoying beeping sound.
• You can't make calls or receive toll-free calls on your circuit. On the other hand, if outbound calls on your circuit are affected, but you can receive dedicated toll-free calls, the problem is most likely with your phone system, not the circuit.
• Everyone in the office is yelling at you to fix the phones. A heightened level of telecom awareness and irritation in your office is a strong indication that your dedicated circuit isn't working right. In this case, just tell everyone not to worry.

Remember Even after you find the source of a problem, repairing it can take many more hours. Dispatching a technician from your local loop provider requires coordination to have someone at your office let the technician into the building. Depending on the technician's schedule and yours, the logistics of setting up a dispatch might push the repair out to the next business day. To prevent your problem from dragging on, the second you realize that you have a system failure (whether it occasionally bounces back or not), push to get it into the queue for a technician as quickly as you can.

Circuits don't always fail and stay down. Sometimes a circuit may bounce, meaning that it fails and then comes back to life, only to drop again and repeat the cycle a few minutes later. A bouncing circuit is problematic, because it requires you to make a decision: You must either limp along and live with the circuit failing every so often or you must let your carrier take the circuit down for 30 to 60 minutes to test the circuit and find the problem. You hardly have any choice at all if the circuit drops so frequently that it might as well be permanently down. On the other hand, if you have just a few hours to go before you can legitimately close down business for the day, you might be better off hanging in there and suffering through the rest of a very long afternoon. Then after everyone goes home, release the circuit for testing.