In times of emergency, communication networks may become congested. Government, law enforcement, and defense departments may find it difficult to coordinate tasks among teams in various locations. In the Public Switched Telephone Network (PSTN), the Government Emergency Telecommunications Service (GETS) number gives precedence to emergency calls to state, federal, and other non-governmental organization personnel. When a user dials a special GETS number, the call is completed on priority. This is because the first switch that detects the GETS number modifies the CPC field in the ISUP IAM message so that the call gets the priority for completion. From then on, every switch along the way provides priority status to this call.
The VoIP networks that use SIP signaling provides a similar mechanism. The Resource Priority Header (RPH) in the SIP signaling message provides the capability to signal High Probability of Completion (HPC) status in a SIP-based network. In the IP layer, the precedence to the packets are identified by the Differentiated Services Code Point (DSCP) value.
GETS provides emergency access and priority processing for both local and long distance telephone calls. Even when the communication network is congested GETS calls are prioritized over normal calls.
This document provides information to set up the GETS functionality in the SBC, GSX, PSX products.
It also provides information about the following:
- GETS call identification
- HPC call Handling
- Call queuing
- GUI changes
- Statistics supported on the EMS
- Other relevant details
This guide is intended for customers who have a good understanding of Ribbon SBC, PSX, and the EMS devices. Customer knowledge and experience is crucial to using the guide. The provisioning information included in these application notes should only be implemented after the customer applies the appropriate SBC and PBX configurations on their servers. You can find installation and configuration instructions in the Ribbon Product Documentation.
Do not use this guide to set up or provision any end-to-end solutions. The guide includes only information recorded while setting up specific scenarios. Ribbon product documentation is often referenced when configuring Ribbon products using the guide since the intent is to use existing documentation whenever possible.
The following Ribbon products include the GETS functionality:
Product Release SBC 8.1 PSX 12.1 GSX 11.1.1 EMS 12.1
Platforms Supporting GETS
GETS functionality is available on the following Platforms.
Product Variants SBC Hardware SBC SWe PSX Hardware HP ProLiant DL360p G8 server PSX SWe GSX GSX 9000 EMS All
Abbreviations and Acronyms
DSCP DiffServ Code Point ETS Emergency Telecommunications Service GETS Government Emergency Telecommunications Service HPC High Probability of Completion Note: Priority calls in the PSX are sometimes referred to as HPC calls IMS IP Multimedia System NGN Next Generation Networks WPS Wireless Priority Service
Term Description COS Ethernet Class of Service EMS Ribbon Element Management System PSX Ribbon Policy and Routing Service PSTN Public Switched Telephone Network RPH Resource Priority Header SBC Ribbon Session Border Controller SIP Session Initiation Protocol (as defined in RFC 3261)
DiffServ Code Point
Emergency Telecommunications Service
Government Emergency Telecommunications Service
High Probability of Completion
Note: Priority calls in the PSX are sometimes referred to as HPC calls
IP Multimedia System
Next Generation Networks
Wireless Priority Service