Telekom Austria has cemented its position as one of the world's most progressive network operators following the deployment of a multivendor 4G core system for VoLTE service trials on the live network at its Serbian subsidiary.

Vip mobile has been used by its parent company as the proving ground for the virtualization of "the entire core network production chain of a voice over LTE service." The move follows a number of trials of individual virtualized elements -- a virtual evolved packet core (EPC), a virtual IMS system and a virtual VoLTE application server -- at Telekom Austria Group subsidiaries in Bulgaria, Croatia, Serbia and Macedonia during 2014.

The "fully virtualized stack," as Telekom Austria calls it, integrates technology from Connectem Inc. (virtual EPC), Metaswitch Networks (virtual IMS) and OpenCloud Ltd. (virtual VoLTE application server). (See Metaswitch NFV Customer -- Vip Mobile.)

Other vendors involved in the trial were Procera Networks (its packet inspection technology is part of the Connectem system), Intel Corp. (Nasdaq: INTC), VMware Inc. (NYSE: VMW) and Red Hat Inc. (NYSE: RHT).

The Connectem system was used for mobility and data session control, Metaswitch's Clearwater virtual IMS system was used for setting up and tearing down packet voice calls and the OpenCloud software for voice call continuity as users transfer between packet- and circuit-switched voice connectivity.

"With its deployment in VIP mobile's commercial network, Telekom Austria Group proves that the technology is ready for prime time," noted the operator in its official announcement, adding that the timing of the successful tests coincides with its tender process for virtual EPC capabilities. While Connectem should feel well placed in that process following the Vip Mobile trial it is not the only proven solution, as Telekom Austria completed a successful trial of virtual EPC capabilities from Affirmed Networks Inc. in Bulgaria last year.

While the latest trial was conducted on the network of Vip Mobile, a relatively small operator that ended 2014 with 2.16 million customers and which has just won a license to offer commercial 4G services in Serbia, the virtualization of multiple LTE core elements means Telekom Austria has the potential to use a single data center deployment of virtual elements to manage and deliver VoLTE (and other data) services in multiple markets: As this map shows, Serbia borders Croatia, Macedonia and Bulgaria, while Austria and Slovenia (another Telekom Austria market) are not far north of those countries.

Now the race is on to see which vendors will get the nod from Telekom Austria for commercial, production network NFV deployments. In addition to the vendors named above, the operator has also conducted virtual IMS and VoLTE application server trials with Mavenir Systems Inc. and will no doubt be engaged in discussions with the major network equipment providers: Ericsson AB (Nasdaq: ERIC) and Nokia Networks are the operator's lead 4G network technology suppliers. (See A1 Telekom Ramps 4G to 300 Mbit/s With Ericsson.)

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The operator's NFV plans are also taking shape in its fixed network too, as Telekom Austria just completed a virtual home gateway trial with NEC and its OSS subsidiary netCracker. (See Eurobites: Telekom Austria Tests Virtual CPE.)

But it's not all about technology: As the operator's CTO Günther Ottendorfer told Light Reading last year, the company's NFV plan involves a major staff training program designed to get the whole company on board with Telekom Austria's virtualization strategy. (See Taking NFV to the People and Telekom Austria Plans NFV Boot Camp.)

All of that will cost money, of course, but the ultimate aim is to become more nimble and more efficient, with the deployment of virtual rather than proprietary hardware-based network elements eventually leading to a reduction in operating and capital expenditures. Telekom Austria is in need of a lower cost base just now following a tough 2014. (See Net Loss Prompts More Cuts at Telekom Austria.)

NFV is set to be one of the hot topics (yet again!) at the Mobile World Congress event in Barcelona next week: Check out all our coverage at Light Reading's dedicated MWC news channel.

— Ray Le Maistre, , Editor-in-Chief, Light Reading