1. Gatekeepers Soh Hock Heng National University of Singapore Internet2 Commons Site Coordinator Training December 3, 2003 National Univesity of Singapore

2. 2 GateKeeper MCU H.323 Clients INTERNET H.323 Videoconferencing Web Browser Real Video H.323 H.320 Gateway ISDN POT’s line Telephone

3. 3 Gatekeepers Provide:  Admission Control  Call Authorization  Address Translations  Bandwidth Management  Zone Management  Call Signal Routing  Management Functions

4. 4 H.323 Gatekeeper  Necessary for operations, but not mandatory in H.323  Required Functions Address translation Call admission/authorization  Some bandwidth management

5. 5 Typical Gatekeeper Components  Gatekeeper Core Functionality  Web Server Management  SNMP Services

6. 6 H.323 Zone  Definition A single gatekeeper and all of the end points (clients, MCUs, and gateways) that register with the gatekeeper.

7. 7 H.323 Zone

8. 8 Basic Operation  Endpoints register with gatekeeper to provide mapping between physical address and alias/extension  Endpoint asks gatekeeper for permission to place call to another endpoint  Endpoint signals call with other endpoint  Endpoints exchange media  Endpoints disconnect, notify gatekeeper

9. 9 Gatekeeper Functionality 'Services Definition' describes the various services (multipoint conferences, h.320 gateways, call forwarding, etc.) that are available on the network 'Zone Definition' provides a mechanism for describing users on the network in the local zone 'Neighbor Gatekeepers' provide a way to define other distant gatekeepers (for example, at other campuses), so that users can make 'long distance' calls 'Network Topology' provides a way to describe topology on the local zone. For example, a local zone may include several high bandwidth LANs interconnected with lower speed T1 circuits 'Network Control' provides functions for setting global network parameters, such as overall network bandwidth dedicated to H.323 conferencing

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11. 11 Client Authorization  Open Gatekeepers- anyone can register  Predefined Endpoints  LDAP Authenticated Endpoints

12. 12 Gatekeeper Services  Services are defined in the gatekeeper to match those defined on the individual devices (e.g. MCU) and define the set of all services potentially available on the network. Services are defined by a dialing prefix.

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14. 14 Gatekeeper Alternatives  Standalone Gatekeeper (e.g. Radvision ECS)  System Blade (e.g. Radvision ECS on a blade of a ViaIP)  Embedded in an Endpoint (e.g. A gatekeeper embedded in a Radvision OnLAN MCU or gateway)  Backup Gatekeeper (e.g. Radvision Alternate Gatekeeper)

15. 15 Specific Example  Radvision embedded gatekeeper Runs in a Radvision MCU or gateway. PC configuration software. Provides parameter setting, remote monitoring and user definition and control. Built-in telnet server. Provides optional monitoring and remote control. 100 simultaneous registrants and 30 simultaneous calls. Free !