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| 7.6 |  | Network Design Issues for Voice |
| 7.6.2 |  | Power protection/options |

Reliable power is vital to IP telephony. An uninterruptible power supply (UPS) can be used to ensure a reliable and highly available infrastructure by protecting it from power failures. Each UPS has some amount of battery that will keep the equipment running for a certain period of time. The UPS can be configured with the appropriate amount of battery for desired results. Most Cisco AVVID products do not ordinarily come with a backup power supply.

Some common strategies for using a UPS include:

- Back up the wiring closet switches and downstream data center using UPS. While this strategy ensures that power is maintained to the phones, wall powered devices such as PCs can still go down.
- Back up the whole building using UPS. This protects all devices and equipment from power failures. Protecting PCs in this fashion is useful because of the new breed of highly available data applications.
- Provide a separate generator for power (besides the feed from the utility company) and use it as backup. In this case a UPS should be added as it usually takes a few minutes for the generator to ramp up. The advantage of this strategy is that less battery time is needed for each UPS.

In addition, UPS can be configured with options such as Simple Network Management Protocol (SNMP), remote monitoring, alarm reporting and so on.