1. Gatekeepers Gabe Moulton The Ohio State University Moulton.13@osu.edu Seventh Annual Digital Video Conference March 31, 2005 Atlanta, Georgia

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

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

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

5. H.323 Zone  Definition A single gatekeeper and all of the end points (clients, MCUs, and gateways) that register with the gatekeeper.  Typically is a community E.g., University or organization

6. Basic Operation  Endpoints register with gatekeeper  Endpoint asks gatekeeper for permission to place call to another endpoint  Endpoint signals call with other endpoint  Endpoints exchange media directly  Endpoints disconnect, notify gatekeeper

7. Gatekeeper Functionality  Services: Gives access to multipoint conferences and gateways  Neighbor Gatekeepers: Provides inter-zone communication  Network Topology: Allow administrator to employ traffic shaping  Endpoints: Live list of registered users  Call Control: Live list of active calls

8. Registrants

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

10. Services  Multipoint Conferences (most prominent use)  Gateways to other services  Defined by a dial string Commons conferences use 3 digits –EG 001189700 accesses a 384K conference  Conferences differentiate by pins Commons uses 4 digits –EG 0011897001234 access my 384K conference

11. Defined Services

12. 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)

13. Gatekeeper Alternatives  Other Gatekeepers: Polycom PathNavigator Cisco (Radvision code running on Cisco IOS) VCON Media Exchange Manager, MXM GNU Gatekeeper (Based on open H.323)

14. 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 !

15. Questions? Gabe Moulton Technology Engineer The Ohio State University 614 292 8443