Using a VoIP Centrex feature gateway -- which typically works with any Class 5 switch -- enables service providers to use existing central office equipment to extend Centrex features over packet networks while providing users the benefits of VoIP service.
In addition, one of those key end-user benefits is the fact that such gateways can reduce enterprise risk exposure to disasters by delivering service over a distributed IP network that can easily reroute traffic almost instantaneously when damaged. In the case of disaster, these gateways also can be deployed rapidly to new locations, such as a warehouse on high ground that is serving as temporary office space after a flood, allowing workers to resume business much faster than with traditional tip-and-ring networks.
Although it leverages the benefits of IP, VoIP Centrex maintains the Class 5 central office switch, which provides a level of proven reliability. Additionally, it takes full advantage of the feature set of the Class 5 switch.
Reliability in the Class 5 switch is not achieved simply because of the fully redundant hardware (there are several other communications platforms that can lay claim to fully redundant NEBS 3 hardware), but also because of the software. This software has been tested through billions of hours of actual user traffic, extensive carrier testing and rigorous proving in vendor labs. A single vendor architecture allows that single vendor to correct interactions between features or different software modules and the reliability of the system is not diminished by intervendor finger-pointing.
While retaining the Class 5 switch portion of the PSTN network, a VoIP IP feature gateway uses a packet-access infrastructure. Fully meshed data networks, properly designed and implemented, offer significant disaster recovery and service reliability advantages over circuit-based networks. While some high-priced alternatives to alternate routing exist in circuit-switched environments, they are clearly cost-prohibitive for all but a small set of enterprises.
Data networks, on the other hand, can be readily designed to provide link failure detection and automatic rerouting of traffic. Because data networks are logical, rather than physical in design, they can handle many situations, including disaster recovery, more quickly and easily than circuit-based equipment. Moving data network equipment tends to be relatively easy compared to moving a complete CO. Multipath designs can utilize redundant paths without human intervention, providing additional layers of redundancy provided by the Internet.
Pre-engineering a network deploying a VoIP Centrex feature gateway for disaster recovery can accelerate the process even further. Detailed contingency plans with equipment-provisioning parameters and prepositioned addresses can be accomplished in a straightforward manner and make recovery much more rapid. Much of this logical network modification could be performed remotely with the proper network in place; thus a network could be configured from any location in the world.
Concerns about power availability for these networks can also be addressed using mechanisms of similar reliability to those available in the CO environment. Data-networking equipment can be powered by AC or DC power as well as uninterruptible power supplies. This flexibility means equipment can be readily located in homes and ordinary office buildings and relocated easily in an emergency.
Any event that causes phone service interruption at the CO also is possible at the worksite. Unfortunately, few worksites are as carefully engineered to withstand such events, as is the CO. In cases where the telephony platform (a PBX or IP PBX, for instance) is on-premises, an event that removes the building from service also can cripple telephony service. That's not the case with a hosted service available from a carrier that has deployed IP digital loop carriers. Fire, floods, and other traumas easily can render a workplace uninhabitable. While corporate data may be backed up off-site for rapid recovery, phone service (at least in the TDM world) often is more difficult to recover after major damage. Using a VoIP feature gateway, this major element of a comprehensive recovery plan becomes simple.
If temporary offices are available, IP Centrex is easy to redeploy rapidly. Voice traffic can be carried on the same network that is being developed for data recovery. Office IP phones that survive the worksite-damaging event can be immediately plugged in and used once a data connection back to a VoIP Centrex Feature Gateway is established.
Teleworking, one of a VoIP Centrex feature gateway's major value-producing applications, enables workers to gain access to their office telephony system while working remotely, even from home. As long as workers can get adequate data connectivity to the company network (or a rapidly deployed, post-disaster subset of the original), they can have full access to their communication environment. This enables a workforce to get up and running even before any alternate office facilities are brought on-line. The seamless nature of this type of communications environment means workers can remain fully productive while working from their homes.
Using a distributed array of smaller regional worksites, including a widely distributed pool of teleworkers, a strategy of geographic diversification is possible. Any individual building event will be confined to a smaller number of workers. If transportation into a central workplace is unavailable or impractical, a distributed workforce can be created easily by using a VoIP Centrex feature gateway as a tool to ensure that a single virtual community is created, even for voice traffic.
Kenneth Arndt is a vice president of marketing for Lucent Technologies Inc. He can be reached at arndtk@agcs.com.
