Emblasoft Evolver offers comprehensive, flexible testing and continuous active monitoring for critical Session Border Controllers, helping you to secure and optimise your IP-based networks.

Session Border Controllers (SBCs) were introduced to manage and control Internet Protocol (IP) communications. They have become essential in controlling and managing real-time communications between businesses and consumers. In the first instance, SBCs were used to initiate, maintain, modify, and terminate VoIP communications, but now encompass all IP-based, real-time communications sessions, including voice, messaging, video, and other internet-based collaboration applications and services – in critical infrastructure, like 4G and 5G networks.

SBCs were originally hardware devices that sat – as the name implies – at the borders or edges of the network to protect and manage two end points in the network, which at first would have been between two service provider networks in a peering environment for the secure exchange of IP-based traffic.

SBCs: The gatekeepers of IP-based communications

Nowadays that role has expanded to include devices that act as a gatekeeper between public and private networks (and so are essential for roaming and for serving mobile, residential and business customers). SBCs are also now more likely to be deployed as software.

Examples might include that of a firewall between a corporate network and the internet, or simply to control the data flow and quality of a video call between two devices on different networks.

IP communications use a tightly integrated suite of protocols for conveying both control information (via TCP, UDP or SCTP), and the data associated with the session (over RTP). A session describes the control messages related to a call as well as statistics regarding call details, measurements, access control, quality, and so on.

When control messages are exchanged to create and manage sessions, the network from which the session is requested needs to both validate the integrity of the control information, as well as to ensure that the network is protected from adverse threats. SBCs provide this border gateway functionality.

As a result, SBCs are an integral component of IP-based communications networks. Moreover, they play multiple roles, including:

• Securing real-time communications from cyberthreats such as spoofing, distributed denial-of-service (DDoS) attacks, and toll fraud. SBCs perform these tasks by:
  • Hiding the topology of the IP network to secure potentially vulnerable parts of the network.
  • Encrypting signalling and media making it harder for malicious actors to decrypt sessions.
• Enabling SIP trunking by providing a termination point for the SIP and RTP connection (referred to as a SIP trunk) into a communications network. SBCs provide the security, interoperability, resilience, and intelligence (for example, where to route SIP calls) to safely connect SIP trunks.
• Interconnecting different networks, protocols and codecs – different networks may use SIP variants according to different vendor implementations. An SBC can translate between different variants.
• Ensuring QoS by assuring network performance through the use of policies and types of service.
• Policy controls and intelligent routing – in larger deployments it can be challenging to manage multiple SBCs, but they enable centralisation so that policies can be applied consistently across the board.

The imperative of comprehensively testing and continuously monitoring SBCs

It’s clear why SBCs are essential to the smooth running of IP-based communications. That’s why it is absolutely imperative to perform comprehensive testing and continuous monitoring of the performance (and resilience and security) of SBCs.

SBCs are, naturally, integral to IMS-based networks – though, of course, 3GPP decided to give the functions that require SBC capabilities different names to distinguish their specific role in the architecture.

The P-CSCF, or Proxy Core Session Control Function, essentially acts as a gatekeeper for access from a UE to the IMS core. In IMS networks that also serve PSTN customers, the BGCF (Border Gateway Control Function) fulfils a similar function, working in tandem with media gateways to convert legacy media into IP.

Similarly, two IMS networks (for example, operator A and MNO B) also interconnect via SBCs — in this case, the SBC capabilities are rolled into the IBCF, or Interconnect Border Control Function — enabling two different IP networks to interconnect.

We could go on, but the point should be clear: SBC are widespread, perform different functions to protect the core IMS network, and enable internetworking and traffic exchange between different operators – for national, international and roaming traffic.

They are pervasive and absolutely crucial to the smooth functioning of critical national and international infrastructure. They protect networks and users from harm – and must process vast and growing traffic flows, particularly as legacy networks, such as the PSTN edge closer to shut-down.

So, a comprehensive, flexible testing platform for all kinds of SBC functions is not just necessary, it’s essential. All operators need a test solution that can perform both functional (UE to UE) and performance testing (as SCBs carry heavy loads), as well as media and signalling testing – across any scenario. They also need solutions that can provide continuous assurance, through active monitoring in live networks, because of the constant vigilance required at these border points.

Emblasoft Evolver, and its new, COTS-based Uranium module, can help you to meet these challenges. To find out how our platform can run comprehensive, end-to-end testing and continuously monitor your SBC estate, download our new paper by clicking here.