Home Africa and the Middle EastAfrica and the Middle East 2014 Session Border Controllers: What are the benefits of SBCs for operators?

Session Border Controllers: What are the benefits of SBCs for operators?

by Administrator
Roger JonesIssue:Africa and the Middle East 2014
Article no.:11
Topic:Session Border Controllers: What are the benefits of SBCs for operators?
Author:Roger Jones
Title:Sales CTO, EMEA
Organisation:Sonus Networks
PDF size:254KB

About author

Roger Jones, Sales CTO, EMEA at Sonus.

Roger Jones has been at Sonus since October 2012.

He is now in his 25th year in the communications industry, the first twelve focused on Local Area Networking technology. Roger then worked at Lucent and Avaya for thirteen years where he was a Unified Communications Consulting Engineer and latterly a UC security specialist based in EMEA.

Roger holds a degree BSc in Electronic Engineering from Sussex University.

Article abstract

When a user attempts to initiate a voice or video session (or other forms of communication, such as instant messaging and presence), across one or more telco networks, Session Border Controllers (SBCs) interconnect the networks with appropriate signalling. They ensure these communications are delivered to the right place, in line with pre-set policies, and that traffic is handled in a way that does not put too much strain on the network.

In today’s highly heterogeneous device environment SBCs are the key element tying together unified communications systems, with new and legacy communications systems such as PBXs (private branch exchanges).

Full Article

I tend to describe Session Border Controllers, (SBCs), as the ‘Swiss Army Knives’ of the telco network, with a variety of useful functions: tour guides, translators, silent guardians, and generalist handymen, SBCs aren’t afraid to get their hands dirty, and are one of the most crucial elements of any network.

Benefits to operators

When a user attempts to initiate a voice or video session, (or other forms of communication, such as instant messaging and presence), across one or more telco networks, SBCs interconnect the networks with appropriate signalling. They ensure these communications are delivered to the right place, in line with pre-set policies, and that traffic is handled in a way that does not put too much strain on the network.

SBCs will often take on some of the core tasks of the network servers in order to route calls based on policy, such as time of day or least-cost-routing, and other services. Number analysis (NA) is another example of a useful SBC function, which determines whether a set of dialled digits represents a valid telephone number (based on number validation, number categorization, or digit manipulation).

In today’s highly heterogeneous device environment SBCs are also the key element tying together unified communications systems with new and legacy communications systems such as PBXs (private branch exchanges).

The SBC acts at the session or call level as the translator between end devices, as the intermediary between different network protocols, ensuring interoperability. As more employees opt to work remotely on their own devices this becomes increasingly important. Even something as simple as normalising a dial plan can be complex, as many legacy PBXs have limited support for how digits can be manipulated. SBCs can manage this call delivery.

Another key function is as one of the primary lines of defence against network intrusions, (hence ‘border controller’). They protect against DoS and DDoS attacks, provide media and signaling encryption, topology hiding, and oversee black, white and grey-listings, ensuring no one can see past the front door to gain information to help plan an attack.

The attack vectors for real time communications such as VoIP and SIP are unique, and data-centric devices aren’t really designed to stop them. In contrast to plain data and TDM voice communications, hacking can be undertaken by intercepting signaling and/or media flowing at any point between two endpoints along the communications path, giving access to other parts of the communications system.

These attacks can take place in many ways. Obtaining confidential information can be achieved by accessing the network under a false identity or eavesdropping on private communications, while toll fraud attacks seek to steal long-distance service by illegally logging onto the network.

As well as guarding against these kind of intrusions SBCs also have extensive roles in billing and disaster recovery. Ultimately, all of the SBC’s functions come down to allowing the service provider to deliver an appropriate QoS level to its customers.

Market drivers and why SBCs mean opportunity

Overall, the market for SBCs, both for Service Providers and Enterprises, is growing by 15% every year and is predicted to have doubled to over US$1bn by 2017 (Infonetics, March 2013).

The reason is clear: Telcos are busily migrating away from older infrastructures to IP-based networks. SBCs are required to handle the growth of such networks, and the proliferation of device types, media and protocols these networks are there to support.

As Service Providers move from Time Division Multiplexing (TDM)-based networks to Session Initiation Protocol (SIP) over IP networks, a major opportunity exists to move Enterprise customers over to SIP trunks. This is a win-win, as it represents a selling opportunity for the network and will drive down the costs for both the Service Provider and the Enterprise as traffic can be routed across the telco network more efficiently using SIP.

The Enterprise will benefit from better integration with their internal networks, better functionality and more flexibility regarding the communications equipment they can use and the number of concurrent calls they can make.

The exponential increase of video-communication within enterprises, with its higher bandwidth, is also likely to drastically increase the session count and traffic volume through interconnected SBCs. This will drive demand for greater numbers of increasingly sophisticated SBCs.

What’s coming up?

SIP trunking in EMEA is likely to grow significantly over the coming years. After all, with lower costs, greater flexibility and often better fail-over provisioning, it’s an attractive option. This, in turn, will drive an increase in demand for SBCs.

In terms of in-office communications, one of the most interesting upcoming developments is WebRTC, an open protocol being developed by the World Wide Web consortium that will allow instant in-browser voice calls, video chats and file sharing, without any kind of ‘app provider’.

We picture this playing a big role in businesses in the near future, and it will simply add to the complexity, behind-the-scenes, of the communications mix. This, together with the general projected increase in video communications, is one reason why SBC companies have recently been focusing on improving their video capabilities.

Another major evolution in the networks is Voice over LTE (VoLTE), which is set to drive further adoption of SBCs. With the bandwidth available on 4G networks, real-time IP communication on mobile handsets is now viable and communications can be further simplified, with more and more traffic transitioned to IP and SIP. This will also need to be policed and managed and as VoLTE will drive a huge increase in session counts, especially as IP-based video comes further into play, demand for high-end SBCs will only increase.

Moving forward, SBCs will need to adapt in order to accommodate Diameter signalling, to allow one 4G network to hand off to another when roaming internationally. When a SIP session is initiated Diameter messages work behind the scenes within the core network to authenticate that the subscriber is who they say they are, is authorized to use certain network services or applications, and is charged correctly for using those services. However, at the moment, due to inconsistencies in the way such 4G/LTE signalling is handled, 4G tends to automatically drop back to 3G signalling when roaming.

Until now this hasn’t been a big issue for service providers simply because of the limited number of IMS subscribers. But as more subscribers move to IMS-based 4G/LTE networks service providers are expecting an exponential growth in Diameter traffic from smartphones and tablets.

Diameter signalling is complex, with over 75 unique interfaces assigned to either IMS or LTE network elements. While a new product category, the Diameter Edge Agent (DEA) is said to work in the same way that SBCs work for SIP, SBCs with integrated Diameter signalling can provide security that DEAs cannot. An integrated SBC/DEA solution makes it possible to realize operational efficiencies and performance improvements on 4G/LTE networks by making common some functions, such as the concept of Network Function Virtualisation (NVF).

Additional resources

For further information on SBCs in general, and the roles they play within a telco network, you can download a free copy of Sonus’ Session Border Controllers for Dummies online.

 

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