Breezy statements about the necessity of the multivendor, cloud-native 5G network are a thing of the past. These goals remain central in the discussions of the largest operators, but they are more focused on the huge challenges of moving to reality – while many tier two players are watching from the sidelines, evaluating simpler options, such as cloud-hosted services, that may emerge over the coming years.
At the 5G Cloud Summit in Madrid, operators were emphasizing the challenges more than the visions in their roadmaps. Enrique Blanco of Telefónica was grittily determined to move towards a multivendor, microservices platform (see previous item) but clear about the hurdles. Deutsche Telekom’s VP of core network development, Franz Seiser, was similarly realistic, telling the conference audience about the telco’s multiyear program to implement a 5G, cloud-native core.
This will run in parallel with converting 900 of its telco locations in Germany into edge cloud centers, or cloudlets, which could host distributed core as well as other virtual network functions (VNFs) for DT’s own network, or to support customer or partner services. So far, central offices in Berlin, Frankfurt, Hamburg and Munich have been turned into cloudlets, and Dusseldorf will be next. The operator is using MobiledgeX, a start-up backed by DT, as the platform for its edge applications development and deployment.
Seiser is keen to use open source technologies wherever possible, to ensure interoperability, reduce time to market, and to access the widest base of innovation in equipment and developers. However, he acknowledges open source may not, in the early years, save deployment cost because of the need for integration, and work to ensure the systems are fully carrier-grade. Therefore, choosing the right open source technologies is vital.
“The challenge is to figure out the right ingredients but also combine them in the right way … You can have the best ingredients and not know how to cook properly,” he said.
After dialling down the pace of a big-bang cloud initiative called pan-net, DT has been starting to move some network functions into the cloud over the course of this year, and some will start to support commercial services next year. Other priorities are to move towards what DT has called “brutal automation” in the network, and Seiser said the biggest gaps lie in orchestration of large numbers of multivendor VNFs, and in changing the internal culture of a workforce unaccustomed to the cloud.
The other big challenge, as echoed by BT and many others, is to optimize open and cloud-based network software to make its performance equal to, or better than, that of a non-virtualized, appliance platform. This currently makes the deployment of vanilla open source systems more expensive than of old-style, pre-optimized functions.
In addition, DT is also having to convert its early virtualization efforts, based on virtual machines, to support the more agile and programmable microservices environment. But that raises problems of its own – notably the complexity of orchestrating huge numbers of microservices, a challenge which makes full automation absolutely critical. And despite its attractions, open source can add to the risk and the complexity, compared to relying on a single trusted supplier to deliver the whole cloud-native platform.
Seiser said DT has been evaluating several suppliers in terms of their ability to combine open source technologies to build a cloud-native 5G core. “The differences were rather big,” he said. “Some were close to and others were quite far away from our definition of cloud-native.” That highlights yet another risk for operators embarking on the road to 5G core – the immaturity of all the solutions, and the conflicting claims and definitions made by the vendors for their ‘cloud-native’ systems.
However, DT has now selected one vendor for a trial of a mixed environment of VMs and containers/microservices, using various open source elements together and integrating them tightly with the cloud infrastructure, with full automation of orchestration and end-to-end monitoring. A common approach is needed so that all operators can address complexity in the same way, otherwise “the software guys will charge like crazy,” Seiser said. That will also mean making choices between the many open source options on the market and unifying around them – the goal of several initiatives such as the Open Networking Foundation, the Telecom Infra Project and the new Common NFVi Telco Taskforce (see separate item).