Networking / Beginners

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Installation made busy: IMB

Installation made busy, or IMB, is a protected state that is usually imposed by your carrier on an entire circuit to prevent it from generating alarms in the carrier's network. For example, if you unplug your hardware from the circuit, your carrier immediately sees alarms at its end of the span. The technician who is listening to the piercing screech of the alarm doesn't have your contact name and phone number, so he or she does the easiest thing to end the maddening alarm. Usually, the easiest thing to do is to busy out the circuit, or place the circuit into the IMB state. The bad news is that when you plug your hardware back in, you won't be able to use it because the carrier has been busied it out.

Remember Every carrier has its own procedure for placing a circuit into the IMB state. The process might be manual, with a policy to wait until the circuit has been in alarm mode for eight or ten hours before busying out the circuit. Sometimes, however, the process is automated; you may have as little as an hour before the carrier automatically busies out your system.

Carrier failure: CFL

Carrier failure is like IMB, because it generally affects your entire circuit, and not just a few channels. The bad news about a circuit in carrier failure is that this state commonly indicates a substantial problem that needs to be addressed pronto by your carrier. If your CSU fails, or if someone accidentally cuts through the wiring of your circuit with a backhoe, or if your carrier's switch sustains a direct lightning strike, your circuit is in carrier failure.

Remember Carrier failure indicates a more serious issue and generally takes several hours to diagnose. After the technician finds the source of the problem, it can be another 4 to 24 hours before your circuit is back in service. Keep this in mind when you set expectations. (In other words, it's time to have a chat with the head of your telemarketing department.)