IPX

Building upon the growing trend of VoIP interconnects, the GSM Association (GSMA) has defined the IP eXchange (IPX) as a managed interconnect service for exchanging SIP-based communications between multiple service providers—mobile operators, fixed line providers and application service providers (ASPs).

The IPX is built by international wholesale and transit carriers using common technical specifications and consistent commercial models and reflects GSMA’s four principles of openness, quality, cascading payments and efficient connectivity. Leveraging the existing GPRS Roaming Exchange (GRX) layer 3 transport network, the IPX adds connectivity to non-GSM operators and supports new interactive IP communication services, new charging models, end-to-end QoS for roaming and interworking.

International wholesale and transit service providers providing IPX services can realize several benefits, including the ability to:

• Increase revenue with seamless, high-quality, secure service interworking between all types of service providers
• Differentiate from competition via value-added services such as transcoding and protocol interworking
• Speed customer “time-to-service” using IP connections with faster provisioning times
• Enable new services that require end-to-end IP connectivity such as interactive video, instant messaging and multimedia collaboration

As service providers continue their deployment of next-generation networks and services, interconnecting to IPX carriers can produce several benefits. These include lower capital and operational expenditures, extended service reach, improved call quality, new services and simplified operations.

Our IPX interconnect solution features our Net-Net session border controller (SBC) deployed at the IPX carrier. It acts as the IPX Proxy—a GSMA-defined function that satisfies requirements for security, service reach maximization, SLA assurance, and cost and revenue management. The Net-Net SBC is also used by fixed and mobile service providers at the interconnect border with IPX carriers to mediate between networks and solve the challenges associated with IP hand-offs between service providers.

Traffic exchanged between service providers over an IPX carrier includes VoIP, IP video telephony, push-to-talk, video share, presence/ messaging, multimedia collaboration and other interactive services using SIP signaling. The IPX offers highly efficient and commercially attractive methods of establishing bilateral and multilateral interworking and roaming interconnection arrangements for interactive IP communication services.

IPX carriers can offer a variety of revenue generating service offerings, including:

• Off-net traffic termination or origination
• Roaming traffic aggregation for all services—voice, PoC, video share, presence/messaging, video telephony
• Hosted interworking services— transcoding, signaling normalization, encryption
• Access to wholesale services and ASPs—directory, IVR, speech-to-text, etc.

The IPX is “service aware” and private—not part of the best-effort Internet. However, interconnecting to service provider customers using IP links does introduce challenges for meeting the GSMA IPX requirements:

• Security—hide and protect network resources from attack
• Service reach maximization—exchange routing information and session traffic across heterogeneous networks with conflicting network characteristics to ensure reachability and interoperability
• SLA assurance—maintain service and network availability during abnormal busy periods
• Cost and revenue management—protect against theft of service, minimize session routing costs and capture session data for accounting and billing

Security

Service reach maximization

IP networks may use different signaling protocols, codecs or overlapping IP address spaces. To enable calls to traverse multiple networks—from a mobile or fixed service provider across IPX carriers to another service provider—Acme Packet Net-Net SBCs mediate between heterogeneous networks and fix incompatibilities. These features allow IPX carriers to increase their addressable customer base and accelerate time to market. By mediating differences at ingress and egress of their networks, IPX carriers are able to change their core network quickly without disrupting the customer interface. IPX carriers can also leverage the GSMA’s PathFinder number resolution database to discover addresses for proper routing for SIP-based communications.

SLA assurance

Oversubscribed networks and service infrastructure can negatively impact IPX carrier network availability and call quality of the service providers’ subscribers. Acme Packet’s SBCs provide session admission control, load balancing and QoS marking and reporting features that deliver assured service quality and network availability during periods of congestion or abnormal network events.

Cost and revenue management

Inefficient network utilization, improper accounting and fraud can reduce IPX service profitability. Proper settlement is essential due to the chain of IPX carriers and service providers involved in delivering end-to-end interactive IP communications. Acme Packet’s SBCs deliver call routing, bandwidth policing and accounting features to aid in revenue collection and ensure the most cost-effective usage of an IPX carrier’s network.