Configuration Examples

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The following pages describe the steps necessary for the configuration of:

  • the Cisco® MCM (Multimedia Conference Manager);
  • the Gnu-gk open source gatekeeper;
  • the Polycom PathNavigator™;
  • the Radvision® Via-IP™ ECS (Enhanced Communications Server). The examples use the fictional college at Anytown, whose domain is * The DNS address of the example gatekeeper is, with IP address The IP address range is: 192.168.x.x and the college’s zone number is 004401234. All addresses used in the examples are fictional (and non-routable). Any real IP addresses in the illustrations have been blurred for security reasons.

These examples assume a basic, simple topology involving only one gatekeeper and associated zone and a small number of H.323 videoconferencing terminals (also referred to as endpoints). It assumes that there is no shared ISDN gateway (although the terminals themselves may or may not be connected directly to ISDN lines – this does not affect gatekeeper configuration). There is also an assumption that there is a single site access router to which all data is routed.

During tests it was found that when the configurations detailed below were applied, it was possible to use the Global Dialling Scheme to call both to and from another JANET-connected organisation’s terminals. In almost every case it was also possible to call to and from the terminals directly using IP addresses (after appropriate configuration of the site firewall). The only exception was the case where the local terminal was registered with the Polycom PathNavigator™, where it was possible to receive calls using the terminal’s IP address, but not to initiate outbound calls using IP addresses.

The following configuration examples are intended as a ‘how-to’ guide to setting up each gatekeeper product for inter-working with local H.323 endpoints and the Janet Videoconferencing-IP. These are not product evaluations, nor is there any attempt to judge the appropriateness of each product for the purpose. Each has its own merits and there are various differentiators between them. URLs for product literature and user documentation have been supplied at the end of each configuration example.