Tandberg Data N3 3.5 Call Control

11

3.5 Call Control

When an end-point wants to call another endpoint it presents the address it wants to call to

the Gatekeeper using a protocol knows as RAS. The Gatekeeper tries to resolve this address

and supplies the calling endpoint with information about the called endpoint. The destination

address can take several forms: IP address, H.323 ID, E.164 alias or a full H.323 URI.

Dialing by IP address is necessary when the destination endpoint is not registered with a

Gatekeeper or Border Controller. If it is registered, then one of the other addressing schemes

should be used instead as they are more flexible.

When an H.323 ID or E.164 alias is used, the Gatekeeper looks for a match between the

dialed address and the aliases registered by its endpoints. If no match is found, it may query

other Gatekeepers and Border Controllers.

When dialing by H.323 URI, the destination address resembles an email address. The

Gatekeeper first follows the procedure for matching H.323 IDs. If that fails it looks for a

Gatekeeper or Border Controller responsible for the domain (the part of the URI following the

@) and queries that device.

NOTES

ARQ, Admission Request. An endpoint request to make or answer a call

LRQ, Location Request. A query between Gatekeepers or Border Controllers to determine the

location of an endpoint.

RAS, Registration, Admission and Status Protocol. Used by endpoints and Gatekeepers to

communicate.

The Figures 1 and 2 illustrate the process the Gatekeeper performs when receiving call

requests.

Contents

Main Trademarks and copyright Environmental Issues TANDBERGs Environmental Policy Environmental Considerations Operator Safety Summary Table Of Contents Page 1 Introduction Page 2 Installation 2.1 Unpacking 2.2 Mounting 2.3 Connecting Cables 2.4 Switching on the System 2.5 Gatekeeper Initial Configuration Page 3 Using the Gatekeeper 3.1 System Administration 3.2 Registration 3.3 Neighbor Gatekeepers 3.4 Alternate Gatekeepers Page 3.5 Call Control Page Page 3.6 Bandwidth Control IP Page 3.6.1 Bandwidth Control and Firewall Traversal 3.6.2 Bandwidth Control Examples Enterprise Branch Office Home Office Home sub-zone Page 3.7 Registration Control 3.7.1 Registration Restriction Policy 3.7.2 Authentication 3.8 H.235 Authentication 3.8.1 Authentication using a local database 3.8.2 Authentication using an LDAP server Securing the LDAP connection with TLS 3.9 URI Dialing 3.9.1 URI Dialing and firewall traversal 3.9.2 Creating DNS SRV records 3.10 Firewall traversal 3.10.1 Calling unregistered endpoints 3.11 Call Policy 3.11.1 Making Decisions Based on Addresses address-switch address otherwise not-present 3.11.2 CPL Script Actions location proxy reject Selective Call Screening 3.11.3 Unsupported CPL Elements 3.11.4 CPL Examples Call screening Call Redirection 4 Software Upgrade 4.1 Upgrading Using HTTP(S) 4.2 Upgrading Using SCP Page 5 Configuring the Gatekeeper 5.1 Status xstatus ? xstatus TANDBERG Gatekeeper User Manual 5.2 Configuration xconfiguration ? xconfiguration xconfiguration <name> xconfiguration <name> ? xconfiguration <name> <param1>: value1 <param2>: value2 Page Page Page Page TANDBERG Gatekeeper User Manual 40 Configuration commands Description 5.3 Command xcommand ? To get usage information for a specific command, type xcommand <commandname> ? Command Usage Description Page 5.4 History xhistory ? xhistory xhistory <name> 5.5 Feedback 5.6 Other commands Page 6 Appendix: Configuring DNS Servers 6.1 Microsoft DNS Server 6.2 BIND 8 & 9 6.3 Verifying the SRV record 7 Appendix: Configuring LDAP Servers 7.1 Microsoft Active Directory 7.1.1 Prerequisites 7.1.2 Adding H.350 objects Create the organizational hierarchy Add the H.350 objects 7.2 OpenLDAP 7.2.1 Prerequisites 7.2.2 Installing the H.350 schemas 7.2.3 Adding H.350 objects Create the organizational hierarchy Add the H.350 objects 7.2.4 Securing with TLS 8 Approvals EMC Emission - Radiated Electromagnetic Interference EMC Immunity Electrical Safety 9 Technical Specifications 10 Index