Aztek Networks 5000I

Transparent Local Proxy for SIP-Based Emergency Stand Alone

Aztek Networks' 5000I is a Transparent Local Proxy that ensures uninterrupted local calling capability and access to 911 emergency services for all SIP-based user agents and access systems within a local serving area. Examples of SIP-based access systems include gigabit passive optical networking (GPON) and other fiber-to-the-home (FTTH) systems, line access gateway devices and multi-service access platforms (MSAP).

Aztek 5000I Features

• Local calling for IP access systems during line cut
• Routes 911 calls locally
• Interoperates with SIP-based FTTH, Gateways and MSAPs
• Transparently monitors SIP registrations when network is functioning normally
• Compact design
• Environmentally hardened

The Aztek 5000I is the ideal solution for ensuring voice reliability in a switch consolidation scenario where a centralized softswitch is serving a large geographic region. The 5000I will provide local calling capability for all SIP-based subscribers served from a remote telephone office should the link between that office and the centralized softswitch become severed or disrupted.

The Aztek 5000I is a compact, environmentally-hardened, NEBS-compliant system with fully redundant processor cards and redundant gigabit Ethernet ports.

How It Works

The 5000I continuously monitors all SIP registrations between local SIP user agents and the distant primary softswitch. If the primary softswitch is unresponsive due to a system failure or line cut, the 5000I examines the registration and determines if it is for a long distance, local or 911 call. If the call is local or 911, the 5000I signals the receiving user agent of an incoming call and allows the local call to be completed. The carrier pre-designates which local user agent(s) are qualified to receive emergency calls in the event of a disconnection from the primary softswitch. Examples of qualified emergency responders could include a local Public Service Answering Point (PSAP) or, if there is no local PSAP, a local fire station or police department. During the disconnection period, the 5000I directs all 911 calls directly to those pre-designated numbers. Once the link to the primary softswitch is restored, the primary softswitch resumes all call control functions including 911 routing.

Figure 1: Example of a broadband central office served by a distant softswitch. All local SIP devices, such as GPON OLTs, MSAPs or gateways, are configured to register with the 5000I, which passes those registrations on to the primary softswith

Figure 2: When a line break occurs, the 5000I becomes a local proxy for the softswitch, allowing for the completion of all local calls and routing all 911 calls directly to pre-designated emergency responders.