BOSTON--Though Verizon is investigating IP multimedia subsystem (IMS) architectures, the company has established no time frame for deploying it, executive director Paul Perry said at the Voice on the Net show in Boston Thursday.

“We’re looking at [IMS]; we think it’s interesting,” Perry said of IMS, the much talked about SIP-based architecture for merging wireless and wireline applications. “We’re looking at what vendors are going to come up with and testing them over time.”

“Our approach is to first deliver a unified interface to our customers and then transform the infrastructure underneath that, and make it easy to transition our customers onto this new network,” he added.

Specifically, Verizon is focused now on two primary pieces of the puzzle: home subscriber servers (HSS) and call session control functions (CSCF).

“HSS is a component we already have,” he said. “We have subscriber data in all sorts of places.”

Verizon’s interest in IMS stems not from the desire to converge fixed-line and mobile infrastructure (one of the technology’s most popular drivers) but from the desire to allow customers to “mix and match” services across wireless and wireline devices, based on a request for proposals the company issued a few years ago.

“We started down this path some time ago, before IMS gelled as a buzz term,” Perry said.

Perry stressed the operational difficulty in Bell companies disaggregating subscriber data and call control functions into separate boxes that interoperate with other vendors’ gear, as IMS specifies. “There’s a lot of work [involved in using] interfaces not defined by IMS that you really need to care for,” he said.

But Verizon sees the value of the architecture, he added.