There are a number of challenges that are apparent with the growing popularity of IP Telephony and one primary issue is regarding VoIP Emergency. In the U.S. and Canada, the 911 service has a built-in feature called E911 or Enhanced 911. E911 automatically associates a civil address with the callback telephone number of the calling party. The system uses software and databases at telephone companies to help emergency responders at Public Safety Access Points (PSAPs) to locate the emergency rapidly with little information from the caller’s end. All Internet Telephony Service Providers (ITSPs) must have implemented Automatic Location Information (ALI), that is, a callback number and location details as mandated by The U.S. Federal Communications Commission for their customers by September 28, 2005 or risk sanctions for non-compliance. The Canadian Radio-Television and Telecommunications Commission (CRTC) stated that all local VoIP service providers in Canada had to inform their existing and prospective customers of the status of 911 and e911 services as provided by them by January 18, 2006.

With IP telephony, each subscriber has a unique port number and IP address, but this is not sufficient to locate them in the event of an emergency. There are a number of technologies available to implement a reverse lookup of a VoIP subscriber’s location. These technologies are not always easily accessible due to the multiple peering nature of the Internet. Also, because of potential inherent mobility of any Internet user, the responsibility must rest on the customer to provide their Address Location Information (ALI) to the ITSP. In this regard, the ITSP should take the appropriate action to force the customer to provide their ALI and keep the information up to date. Moreover, the ITSP must receive and maintain a record of an electronic confirmation for the release of customer ALI to PSAP operators.

Dialexia’s Dial-Gate® softswitch could be configured to redirect all VoIP Emergency calls to an Emergency Service Provider (ESP). An Emergency Status List displays a table of users with their Disclaimer Status and Date, PSAP Configuration, PSAP Status and User Status (either active or inactive). There is also an Emergency History screen and a form for customizing the Emergency System ALI Profile. Dialexia’s solution is easily configurable via a Web browser-based graphic user interface (GUI).

VoIP service providers need to address these distinct areas of Emergency services:

·    Survey regulatory organizations and laws in all countries where VoIP service will be offered.

·    Carefully select PSAP providers.

·    Design a resilient infrastructure network with a very high level of availability. Perform this task at the VoIP service provider’s premises and, if possible, at the customer’s premises.

·    Inform and train customers, both new and existing, of the VoIP Emergency capabilities and limitations of your service. Make sure nomadic customers are aware of the consequence of their mobility in case of an emergency call.

·    At the VoIP service provider’s premises, run Dial-Gate® software and all individual components, software and hardware, in a redundant configuration.

·    Monitor and test the system frequently.

Furthermore, make sure to design, provision, administrate and test systems with respect to regulatory organizations and laws in all countries where VoIP services are being offered.

Network infrastructure design could have a huge impact when a regional emergency situation occurs, since a high volume of calls could flood your system. Many elements must be taken into account when preparing your network for resiliency and high availability. Here are some of them:

1.  LAN- Limit access of the main system components to essential services. At the network level, make use of NAT/NATP, Firewalls, Access Lists, Managed Switches and Intrusion Detection Systems. Ensure that there is no single point of failure.

2.  Electric Supplies and Environmental Conditions – Plan for UPS & generator backup, auto-restart capability & system monitoring. Maintain recommended equipment operating temperatures. Ensure that there are 24/7 fast service response contracts for UPS system problems. Take into consideration your VoIP Server, Gateway IP-PSTN, Internet Link and ISP.

3.  At the customer’s premises, select an Integrated Access Device (IAD) with failover capability when proxy/registrars are not available and deploy one that uses batteries. Install your server and gateway in a redundant configuration. Design a solution with no single point of failure and choose your server with quality in mind: A high processing, rugged computer is recommended.

4.  Spatial Redundancy: Check that your VoIP system has multiple outgoing routes. Set your IT servers in redundancy mode. Use disc mirroring with hot swappable capability and a computer with dual-power supplies, dual Ethernet NICs, etc. Set your Database Management System to high availability mode.

Finally, the onus falls on the Internet Telephony Service Provider to put adequate processes in place to monitor the system frequently and test regularly for the proper delivery of VoIP Emergency calls and the ALI synchronization process with the PSAP provider.

Using Dialexia’s SIP-based Dial-Gate® softswitch solution, ITSPs can ensure compliance with VoIP Emergency standards and eliminate the need for data to be stored at the carrier. Dialexia’s system enables detailed ALI profiles to be sent directly to the PSAP. By using the procedures for emergency preparedness outlined in this article, Dial-Gate® system administrators can guarantee the stability of their hardware and network in the event that a regional emergency occurs. Defining the criteria that solve VoIP Emergency issues is an ongoing challenge. The advanced functionality of Dialexia’s robust Dial-Gate® softswitch alleviates concerns with regards to this key topic.