Avoid putting all your eggs in one basket with redundant networking
Unifying communications via an IP network is a little like putting all of your eggs in one basket: It is convenient as long as you can rely on the basket.
The key to making voice over IP reliable? “Redundancy,” said Mark Cabry, lead telecom engineer for Delaware’s Technology and Information Department. “Redundancy is the key to it.”
Delaware links islands of VOIP
Delaware is in the process of centralizing VOIP services for its agencies, eliminating reliance on a carrier’s local central office resources and replacing them with reliance on the carrier’s backbone, which in Delaware’s case is Verizon.
The backbones usually are reliable, but they are not perfect, and outages happen. “We haven’t had the problem yet, but we know it’s coming,” Cabry said. “When it does go down, it will be an enormous outage.”
His department is providing redundancy through two enterprise session border controllers that handle VOIP traffic internally and pass it onto the carrier network that's located in separate data centers.
Multiple links to the carrier are being provided, with several primary rate interface connections to provide multiple backup data and signaling channels to reduce the effect of an outage in any part of the network.
Ideally, redundancy will be built into a communications system from the beginning, but the funding for it is not always included in a budget. Eventually, the money will become available, Cabry said. If you don’t get money for redundancy upfront, it will come after the first major outage takes telephones off-line.
William Jackson is a senior writer of GCN and the author of the CyberEye blog.