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Diameter Testing: Enabling the Reliability of Critical Functions in IMS, 3G and 4G Networks

With increasing complexity in mobile networks, operators are facing increasing challenges to ensure the performance and availability of the signaling network, particularly with the Diameter protocol, which enables critical functions in the IP multimedia subsystem (IMS), and 3G and 4G long-term evolution (LTE) networks.

What is the Diameter protocol and how does it really impact network performance?

The Diameter protocol’s roots date back to 1998, when the protocol’s specification emerged from a need to replace the traditional remote authentication dial-in user service (RADIUS) protocol for authentication, authorization and accounting (AAA) services in networks. Diameter supports not only AAA but also two other transport protocols: stream control transmission protocol (SCTP) and transmission control protocol (TCP)—and optionally, transport security is provided by transport layer security (TLS). As a result, everything today that is connected to a network or part of a network uses the Diameter protocol. What’s more, the Diameter protocol is used for policy and charging control (PCC), short message service (SMS), mobility management and subscriber management, making it the lifeline of the signaling network: Network elements (NEs), such as call session control function (CSCF), mobility management entity (MME), home subscriber server (HSS) and application server (AS) use it to communicate with each other to get the data they need.

The growth in Diameter traffic in networks shows no signs in slowing down, due to many factors, including:

  • Increasing smartphone subscriptions
  • Exploding data traffic growth
  • Evolving network complexity
  • Subscriber roaming between different access networks
  • New services, including both over-the-top (OTT) and telecom services, such as machine to machine (M2M), LTE Broadcast and VoLTE

Indeed, a growth in Diameter signaling traffic is normally a good sign for operators, with increasing revenue and customer monetization. However, the problem arises when a network failure triggers an enormous amount of Diameter signaling traffic—when droves of devices initiate automatic reconnection requests. The number of sent and received signaling messages then skyrockets, putting rapid and major pressure on all parts of the network.

This is where reliable, high-performance simulator testing becomes paramount. Network equipment manufacturers and mobile operators need to verify their wireless networks by recreating and simulating real-world traffic patterns of millions of subscribers accessing VoLTE/SRVCC, WebRTC, small cells, and Wi-Fi offload services in their labs prior to deployment.

But what is the most efficient way to achieve this?

With our latest app note, entitled EXFO Diameter Testing, we provide a comprehensive overview of Diameter testing and how our QualityAssurer Series of simulators, in real use cases, can effectively help operator clients effectively carry out policy and charging rules function (PCRF) and diameter routing agent (DRA) tests. If you are wondering how to verify your Diameter elements in the lab before your next deployment, be sure to read it today!

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