Policy support for H.323 call handling

The need for policies to control calls is justified by the changing face of communications. An overview is given of a general architecture and language for policies. It is then shown how these are adapted for control of calls using the H.323 multimedia communications standard. Policy support for H.323 was created by extending an open-source gatekeeper. The core policy language has been specialised to deal with call control in general, and for H.323 in particular. Examples are given of policies for H.323, illustrating how traditional features can be made to work more flexibly through use of policies. Examples are also provided of policies specific to H.323, and policies that can take advantage of other information such as the context of a call.