T-Mobile's LTE network to use Tekelec's Diameter signaling router

As part of its $4 billion network modernization project, T-Mobile USA will deploy Tekelec's Diameter signaling router in the upcoming buildout of its LTE network.

A Diameter signaling router provides a central control point to direct messages controlling network policies, charging data, mobility management and authorization across networks using the Diameter protocol, which links various elements in LTE networks. Those elements can include policy and charging rules functions (PCRFs), home subscriber servers (HSSs) and mobility management entities (MMEs), among others.

T-Mobile is wise to implement a Diameter signaling router as it begins to build its LTE network, which is slated to launch in 2013, because that will make it easier for the operator to scale future service, add new elements and handle different flavors of Diameter from different vendors as needed, Houck Reed, Tekelec vice president of project management and operations, told FierceBroadbandWireless

Some LTE operators did not implement a centralized Diameter traffic routing function at the start because it was initially overlooked in the standard, he said. "Everyone sort of assumed the network would take care of itself," he said.

The theory was that IP networks would not have the same issues as legacy signaling networks and therefore best effort data delivery would be acceptable and traffic congestion and mediation would not be problematic. However, operators quickly found that there were significant complications in their LTE networks due to the real-time nature of Diameter, the fact that data traffic is unpredictable and the need for mediation between different network elements.

"Now that we're beyond the first adopters of LTE, it's been well established in the marketplace that you need a Diameter routing capability, not just a Diameter agent but a core routing capability to manage all that traffic because it's such an enormous amount of traffic," said Reed.

LTE operators that did not implement Diameter routers are now going back and adding them in or trying to figure out how to do so "because they've got to architect it back in" if they did not deploy the routers initially, Reed said, noting the meshes created by having all Diameter-based element communicate with one another via direct signaling can be especially challenging to untangle.

Diameter routers are designed to prevent signaling storms, which can cause congestiong and service disruptions, by spreading signaling volume across multiple network elements such as charging systems, policy servers and subscriber databases.

In addition, they help operators create new business models, said Joanne Steinberg, Tekelec director of strategic marketing. Adding value to over-the-top applications, launching personalized service tiers and adding shared data plans all generate Diameter traffic on LTE networks. "So if you want to prepare for these new monetization models it's really important to have this core signaling infrastructure," she said.

Tekelec said it now has 19 Diameter signaling router customers, including five Tier 1 LTE operators in North America.

Tekelec is the Diameter signaling market's early leader, but Infonetics Research says it expects at least 15 vendors to have Diameter signaling controllers by the end of 2012.

In a February report, Infonetics predicted a 106 percent compound annual growth rate (CAGR) in vendor revenue from the Diameter signaling controller market through 2016. Besides Diametriq and Tekelec, other vendors in the arena include Acme Packet, Alcatel-Lucent (NASDAQ:ALU), Alepo, Amdocs, Aricent, Comptel, F5 Networks, Openet and Traffix.

T-Mobile has said it will invest $1.4 billion in building out its LTE network this year and in 2013, with total investments for overall network modernization and LTE deployment expected to reach $4 billion.

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