Hosted IP Centrex benefits explained

Centrex is an acronym for Central Office Exchange, a technology-based solution that provides telephone services across a public network to individuals and companies. However, the service-based technology is not exclusively limited to voice-related services and Internet protocols.

IP Centrex brings the flexibility of the Internet to the service and can be a set of specialised business solutions, where the equipment providing the call control and service logic functions is owned and operated by the service provider, and hence is located on the service provider's premises.

Since Centrex frees the customer from the costs and responsibilities of major equipment ownership, Centrex can be thought of as an outsourcing solution.

In traditional Centrex service (ie, analogue Centrex and ISDN Centrex), call control and service logic reside in a Class 5 switch located in the Central Office. The Class 5 switch is also responsible for transporting and switching the electrical signals that carry the callers' speech or other information (eg, faxes).

IP Centrex builds on the traditional benefits of Centrex by combining them with the benefits of IP telephony. One of the benefits of IP telephony is the increased utilisation of access capacity. In IP Centrex, a single broadband access facility is used to carry voice streams for many simultaneous calls, but in addition, IP Centrex provides a lot of features not previously available with traditional Centrex solutions.

This also leads to the increased utilisation of access capacity. This means a single broadband access facility can carry voice streams for simultaneous calls. IP Centrex incorporates elements and benefits of IP telephony, and voice conversations can now be digitised and packetised for transmission across the network. IP Centrex creates a number of IP telephony solutions, where Centrex service is offered to customers who transmit calls to the network as packetised streams across a broadband access facility.

One of the many benefits of IP Centrex solution is that it allows the end-user to scale a solution to meet the operational requirements of their business. The technology can provide a service to two or 50 000 users that is identical. The only real constraint is that additional bandwidth would be required to service the 50 000 users, but the mechanism used from an end-user perspective is the same.

Centrex frees the customer from the costs and responsibilities of major equipment ownership.

Hercules Schoombee is MD of Aastra Telecom SA.

Normally, provisioning takes place on three levels: operator, IT manager and end-user. It is therefore possible for the IT manager to provision company requirements while allowing the end-user to provision their own needs within the parameters set by the IT manager.

Depending on the IP Centrex solution provided, a normal Web site interface is used by end-users to login and perform tasks. The provisioning of these services is done seamlessly at the back-end of the solution.

Provisioning could be downloading phonebooks, caller line identification and setting up follow me rules, such as prioritising personal and customer calls through the identified caller channels. An IP Centrex solution allows fixed, mobile and soft-clients ie, users on a laptop or PDA, to be integrated with one another creating a platform for SIP (session integrated protocol) technology to be efficiently utilised.

Depending on provisioning selections, it is possible to order add-on modules for the SIP terminal to convert it into a receptionist console, and also to use the hosted IP Centrex solution to provide all the normal features associated with a receptionist console.

The SIP terminal is closely integrated with the IP Centrex SIP Application Server, and it's possible to reconfigure SIP terminal by merely changing user configurations on the IP Centrex Web site. Users simply have to subscribe to a different service and everything else is done seamlessly.

Within South Africa, the largest inhibiter for offering any number of phones as part of an IP Centrex solution will be the cost of the multi-protocol label switching network to provide quality of service (QOS) features.

Various VOIP companies do already provide VOIP services via ADSL, but as a company grows, it will find that ADSL in the format it is currently being offered within SA doesn't provide for QOS. At some stage it will be required to subscribe to leased line (Diginet) service, as it is more commonly known, to have access to good quality VOIP services the whole time.

* Hercules Schoombee is MD of Aastra Telecom SA.