Traditional signalling service takes the connected world back to the future

14 August 2015 | Robin Kent

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Robin Kent

Blog Author | Adax; Director of European operations


If you were to talk to your average mobile phone user, 4G LTE access and over-the-top (OTT) applications would be at the top of their list of network and handset demands. We’ve heard for many years now that SMS is in terminal decline, voice calls are dying a slow death and that an all-IP network has taken over.

If you were to talk to your average mobile phone user, 4G LTE access and over-the-top (OTT) applications would be at the top of their list of network and handset demands. We’ve heard for many years now that SMS is in terminal decline, voice calls are dying a slow death and that an all-IP network has taken over.

While there’s certainly been an overwhelming appetite for LTE and the promise it brings of being part of the ‘connected world’, fundamentally, all handsets continue to offer call and text capabilities, and because of this, SS7 remains an important signaling service.

The death of SS7 as a mass market signaling protocol was predicted in the early 2000s. But since the start of the year we’ve seen a big revival, and in some areas, large growth.

One major reason for this is that the reliability of SS7 has proven to be a major strength compared to that of the all-IP network. Quality-of-Service (QoS) should be paramount for any operator, and as such, reliability is critical for achieving a high service level. Due to substandard IP transmission between the Signaling Transfer Points (STPs) and Mobile Switching Centres (MSCs), we’ve heard of critical cases where some areas have been out of communication. 

Operators have had to fix the problems posed by inadequate IP transmission, and as such, have fallen back on the trusted SS7, to ensure that a high level of service remains. Network Service Providers are continuing to make the migration to LTE but the complete all-IP network will still be a while in the making.

Legacy connectivity for voice and SMS remains an absolute requirement for connecting media gateways, STPs, switches, databases and other telecom applications between legacy circuit switched architecture and IP networks. 

The number of possible SS7 protocol stack combinations is growing depending on whether it is used for specific mobile or intelligent network services and whether the transport is over IP, ATM or even Time Division Multiplexing (TDM) networks. SS7 is becoming so important that instead of being called ‘legacy’ it is now referred to as ‘traditional’. 

The second major reason why SS7 continues to grow is the use of SMS in business. It’s clear that SMS is not as popular among end users as a form of communication like it was 15 years ago.

Despite a drop in end user usage, businesses are now turning back to the future with SMS payments. It’s often the simplest technologies that provide the easiest solutions, and it’s become clear that SMS payments are underpinning the rise in mobile wallet applications; a trend that’s even more prevalent in developing markets where end-users have a greater access to mobile phones than bank accounts.

Statistics show that mobile payment transactions are set to rise globally from $235.4 billion in 2013 to $563.4 billion in 2016. As a result, there has been a rise in SS7 enquiries for Short Message Service Centres.

The move to the all-IP network with the rise of LTE has not been as smooth as predicted so it’s become vitally important for networks to make sure they have a signaling service in place that they can rely on.

It is inevitable that in the future, most telecommunication infrastructures will be based on IP systems but until then, operators need to manage the transition as smoothly as possible and this is why SS7 lives on and continues to be a benchmark for signaling protocols.