1. VoIP – Gateway/Gatekeeper Design Requirements An Examination Ricardo Estevez CS 522 / Computer Communication Fall 2003

2. Big Picture

3. Precise Picture

4. Gateway and Gatekeeper Signaling

5. Gatekeeper and Directory Gatekeeper Signaling

6. Gateway/Gatekeeper Design Requirements Many areas to examine, let’s discuss the following – Zoning – Normalization – Traffic Engineering – High Availability

7. Gateway/Gatekeeper Design Requirements Zoning – NPA-NXX – Numbering Plan Area NPA - Prefix – Several gateways form a zone – 1 or more zones can register with a single gatekeeper – Gatekeeper will choose zone based on prefix lookup – Gatekeeper will choose terminating gateway based on priority

8. Gateway/Gatekeeper Design Requirements Normalization – Use Directory Gatekeepers (DGK) for global routing – Use Gatekeeper for local routing Traffic Engineering – Grade of service – Traffic load – Trunk size

9. Gateway/Gatekeeper Design Requirements High Availability – Gateway declares its degree of availability via a Resource Availability Indicator (RAI) – RAI thresholds are set – A gatekeeper will favor a gateway for call handling RAI threshold is not exceeded – Increases call completions Alternate Gatekeeper and DGK

10. References Durkin, James F. Voice-Enabling the Data Network. Cisco Press: Indianapolis, IN. 2003. ISBN: 1-58705-014-5