Coping with LTE signalling traffic

As network traffic increases, operators are constantly on the lookout for technologies that can help them better manage network congestion and provide better load balancing between the various nodes. Coping with data growth involves facilitating interoperability between various diameter network elements so that the network can scale better.

With the advent of LTE/EPC and IMS – technologies for which Diameter is the standardised signalling protocol for authentication, charging, policy control and mobility – there is an increasing need for native IP signalling and a Diameter Signalling Controller.

Together with the migration of the call control signalling to SIP in IMS, the Diameter protocol is one of the pillars in the transformation of network signalling to native IP based protocols. Diameter is taking over the role that SS7/SCCP has for non-call related signalling in the legacy mobile networks, including in the roaming interface between mobile operators.

Originally used for charging, the flexibility of Diameter routing will see it being used for far more than this across the next few years, argues Nitin Arora of Tekelec. The majority of Tier One and Tier Two operators across the Indian subcontinent already have a lot of components in their networks which support Diameter Signalling and Routing.

“Whether a smartphone’s applications are being used or not, they have a signalling link with the cloud or the service provider’s domain, meaning that in certain markets signalling traffic is 30-50% higher than data traffic”, he says.

The growth of signalling traffic necessitates the creation of a different type of network. “Previous ‘mesh’-style networks connected the various elements of the network much as the name suggests, and on a packet core/data side, it’s still possible to connect the components in this way – maybe 3 gateways, 2 signalling gateways, some policy control functions and charging solutions”, notes Arora.

However, adding in the reporting tools and OSS/BSS systems makes the network increasingly complex. If the data and signalling traffic then increase 100-fold, so to do the network components – and then, a mesh connectivity is no longer feasible. This is where diameter comes into play – the DSR collects the elements in an intelligent manner while providing the same level of routing and assurance.

In addition, if subscribers enter an area where coverage is not provided, their device may automatically select another operator – in this situation, they will expect the same end user experience and quality of service despite being on a roaming network. DSR is crucial for providing this while keeping the networks secure, retaining sensitive subscriber information and passing on only essential information to the foreign network.

One advantage of DSR in terms of revenue is that in a machine-to-machine scenario, the number of machines feeding data into the network will be significantly higher than the number of subscribers. This creates a huge amount of signalling traffic, but the DSR provides the flexibility not only to optimise the network but to provide easy scalability. It also provides secure connectivity for different machines.

“While voice growth is largely stagnating, data growth is surging ahead, but even this pales in comparison to growth in signalling traffic”, concludes Arora. “The next two years or so will see a massive rise in demand for these protocols due to a huge rise in data and signalling traffic.”

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