A gateway device is required in a Lync Server deployment generally for PSTN connectivity, however might be required at a location for the one or more of the following reasons:
- PSTN Connectivity (T1/E1/POTS/SIP Trunking)
- Connectivity to PBX’s or Unsupported IP-PBX
- Survivability (WAN outage)
- Connectivity for existing SIP headsets
- Optimisation of media traffic for users at a location (Media Bypass)
- Normalising of numbering between Lync and foreign network systems
- SIP normalization via SIP message and header manipulation
- Support Analogue Devices
- Fax Machines
- Conference Phones
- Alarm Systems
- Data Modem
- Credit Card Machines
- Transcoding of media between Codec’s
- Conversion of different signalling types and protocols
- Management of Call Routing
- Regulatory Requirements
- In-Country Regulation prohibiting the use of VoIP services (or VoIP restrictions)
- SIP Trunking
- In-Country Emergency Dialling (where it cannot be provided by SIP trunking provider)
- In-Country Short-Number Dialling (where it cannot be provided by SIP trunking provider)
- Issues with call forwarding issues
- Security (to protect corporate network from the SIP trunk providers network)
- Session Border Controller (when using distributed SIP trunking)
- NAT transversal (when using SIP trunking across the Internet)
- Connectivity to SIP trunking provider
- Enhanced Management (Session Limits, Routing Paths)
- IPv4 to IPv6 Internetworking
