Disaster recovery, or more properly avoidance of business interruption, has become a key element of network planning. Enterprises require always on services – there’s no room for downtime when you have customers, or employees, depending on the network. This is especially true with voice applications that are mission-critical to any business.

SIP trunking enables the enterprise to use the strengths of the Internet and solid network planning to provide high reliability and an almost instantaneous recovery in the event of a disaster:

• Rerouting to another office – SIP trunk traffic can be rerouted to a secondary office to ensure that business continues to run smoothly even if one location goes down.
• Redundancy with multiple ITSPs – With an E-SBC, businesses can shift traffic to alternate service providers should the service from one go down.
• Redundancy with multiple PBXs – Similar to the previous comment, the enterprise can install multiple instances of the PBX (News - Alert). In the event that one of those does not respond, the E-SBC can automatically reroute the traffic to an alternate instance of the device.
• Redundant E-SBCs – Good practice dictates that there should be no single points of failure. Just as there may be multiple service providers and PBXs, good practice also recommends that the E-SBC be installed as a failover pair, where the second unit can automatically start processing calls if the first unit fails.
• Security – The architecture needed to implement SIP trunking should also incorporate security features to avoid business interruptions perpetrated by malicious attackers. E-SBCs can protect against denial-of-service attacks, which are a major source of business interruption, prevent theft of services which may cause serious financial harm to the business, and detect and prevent network intrusions.

Besides the cost and productivity benefits of SIP trunking, enterprises can also benefit from the inherent robustness of the Internet and gain advantages that support the business continuity objectives of the firm.

Steven Johnson (News - Alert) is president of Ingate Systems (www.ingate.com).