NICE, France -- Management World 2013 -- Operators that think they've tackled signaling on 3G are in for a new world of hurt on LTE, with their forthcoming voice-over LTE (VoLTE) services bringing the biggest signaling storm with them.

According to Tekelec, which leads the market for Diameter protocol signaling routers, VoLTE will be the single biggest signaling issue on 4G LTE networks.

Signaling happens in the network core and in the RAN where chatty apps have been known to cause widespread outages. Tekelec tackles signaling at both levels, with policy in the RAN and with its Diameter Signaling Router in the core. While VoLTE will affect both, its biggest impact will be in the core. Here, any data traffic that calls for advanced policy and charging rules, new data plans, quality of service guarantees or personalization will add to the storm.

This wasn't the case on 3G voice where operators only did charging and rating. Once voice becomes just another data service, and one that they will want to personalize, they'll see a rise in signaling, says Michael Heffner, Tekelec's director of product management.

"When you want to exert control and monetize it, it generates more [signaling] traffic," Heffner explains.

To help on that front, Tekelec announced the latest version of its policy server Monday at Management World that takes into account VoLTE services. It gives network operators the ability to request different types of bandwidth depending on the device and service being used. If it's an enterprise user, for example, the operator could put a quality of service control into place or zero-rate the voice traffic. (See Tekelec Enhances its Policy Server.)

Last month the vendor also introduced a new version of its Diameter Signaling Router that added support for priority emergency VoLTE services, as well as scalability and routing functions to reduce signaling network complexity in the core. (See Tekelec Updates Diameter Router.)

The company is planning to release its follow-up LTE Diameter Signaling Index next month. It first released the report in September of last year, predicting that Diameter signaling traffic growth will more than triple mobile data traffic growth through 2016. Now, with LTE more widely deployed, Joanne Steinberg, Tekelec's director of strategic marketing, says she expects the compound annual growth rate of signaling to be lower, but the total amount of traffic to increase. (See Diameter Matters.)

The move to VoLTE isn't an issue for a vendor like Tekelec, which just treats it as another data service, but it has caused the operators some integration headaches. In the U.S., most are prepping for rollouts at the end of this year or early next. Verizon has frequently stated that it's waiting until the experience is perfect before its marketing department approves any commercial launches. (See AT&T Promises 4G Voice Launch This Year and Verizon Preps Network, Waits on Marketing Nod for VoLTE.)

"We're engaged in several VoLTE rollouts from a policy and Diameter signaling perspective," Steinberg says. "We'll see mass scale towards the end of the year."

— Sarah Reedy, Senior Editor, Light Reading