IPX - IP Packet eXchange
With the explosive growth of mobile broadband IP networks, global interconnectivity for data applications such as email and web browsing has become paramount. Mobile operators are reacting to this by adopting a structure that consolidates the number of interconnects and increased efficiency. This has been referred to as “hubbing” and is a common practice for interconnecting mobile data networks today – as evidenced by GPRS Roaming Exchange (GRX) and Multimedia Messaging Service (MMS) hubbing networks. With the explosive growth of mobile IP communications and services, mobile operators are now rolling out a new services architecture called the IP packet eXchange (IPX) under the auspices of the GSMA to provide voice and multimedia services such as video sharing, conferencing, presence and gaming, that supports flexible interconnect paradigms.
The IPX network facilitates both bilateral and multilateral interconnects between operators. The IPX networks can be envisioned to provide varying levels of control over the interconnect relationship. There are three types of Interworking Service that the IPX provides:
Transport/Transit only: In this case, the IPX network essentially provides an interconnection “pipe” between the interconnected operators. The operators may have a bilateral agreement already in place, and they may be using the IPX network for transit purposes only. The IPX network is agnostic of the type of application or media that is flowing through the network and may charge the operators for the amount of content that was transferred.
Service Transit: In this case, the IPX network is aware of the types of applications that are being transported across the network, and cascade payments come into play here. The IPX carrier bills the operators based on application-specific parameters. For instance, for a video share application, it may be based on video throughput and duration. The interconnect relationships may be bilateral or multilateral.
Service Hub: In this case, the IPX network provides a complete multilateral hubbing service. Cascade payments will play an important role and operators set up single contracts with IPX carriers for their complete interconnection needs.
The IPX network plays a crucial and beneficial role in quality interconnects between mobile operators and also between mobile and fixed operators. The critical element in an IPX network is the IPX Proxy. The IPX Proxy’s main functions are to provide interoperability between the two interconnected networks and also ensure quality of service for the media stream. The IPX Proxy is slated to be in the signaling and media path of every session flowing between the two interconnected networks.
Interoperability: The interconnected networks may have different core infrastructures, and hence interworking between the networks becomes an important problem to solve. For instance, the mobile core infrastructure may be IP Multimedia Subsystem (IMS) compliant, and the fixed operator core may be pre-IMS. The IPX Proxy ensures that the signaling and the media flows between the interconnected networks are interoperable.
Policy: As IPX networks are “hub” networks, they may interconnect many operators together. However, each operator may have different interconnect relationships with other operators, as well as with the IPX network. This places a burden on the IPX network to carry and deliver quality services irrespective of the type of relationship. The IPX network codifies the interconnect relationships and business models into a set of network policies. These network policies are enforced by the IPX Proxy for high quality carriage and delivery of services, whether the IPX business model is transit, service transit or service hub.
Security: The IPX Proxy enforces the security policies of an interconnect, and also thwarts malicious attacks that can defeat the interconnect Service Level Assurance (SLA) established for the interconnect.
Accounting: Accounting for all sessions that flow across an interconnect is an important component of enabling cascading payments as well as the various business models that are built on top of it. All sessions flow through the IPX Proxy, and the IPX Proxy produces Service Detail Records (SDRs) for all the sessions that go through the platform that facilitate interconnect billing and cascade payments. The SDRs may contain not only duration information for the session, but also other qualifying information such as type of media and codec, type of application, bandwidth and throughput consumed, etc. This enables the IPX carrier to have a comprehensive view of resource utilization so that appropriate billing may happen.
The Verscom IPX Solution
Verscom offers IPX solutions to mobile operators, fixed operators and IPX carriers allowing them to interconnect through multiple modalities – transit, service transit and service hub that enables efficient IP interconnects that will enable rapid service delivery and a fair value chain for the service transit such as messaging, video share and gaming. Verscom’s intelligent solutions at the network edge meet challenges for:
Billing and Settlement: Authoritative SDRs are produced for every call through the solution platform. Appropriate information about the session may be produced using flexible SDR generation and formatting.
Service Level Agreements: Our solution allows collection of various SLA metrics like QoS data, concurrent calls, and bandwidth and also allows the operator to take action based on monitoring these metrics.
Routing: Various forms of routing using URIs, domains, ANI, DNIS, trunks, and ENUM are supported.
Allocation of Network QoS: Our solution can allow the operator to classify the application and associated media into QoS classes for allocation of network resources. Relative QoS is supported using DiffServ and IP ToS.
Managing Interconnects: The Verscom solution allows provisioning of interconnects and their management, including physical devices, networks, etc. The IPX platform can connect to IMS networks as well as pre-IMS networks.
Call Admission Control (CAC): Call Admission Control allows prevention of unwanted traffic into the network as well as internal routing of calls based on run time state of the network (for example load).
Security: The Verscom solution prevents DoS attacks and malicious traffic from entering the operator’s network.
