AT&T’s CTO, Andre Fuetsch, always manages to inject a new shot of excitement about the US giant’s network transformation, when he shows up at industry events – even at a time when there has been considerable speculation that AT&T is backing away from some of its more visionary statements about 5G architectures, and particularly from using new entrant vendors or extensive multivendor deployment.
Certainly, its approach is evolving. It is becoming more and more focused on public cloud – initially for IT and back office applications, but now Fuetsch has confirmed what always seemed logical, that some network functions would be hosted there in future, rather than on AT&T’s own cloud.
One area where there is proof that AT&T is driving forward commercial use of the open platforms it has championed in the MNO world is in white box routing and switching. It has contributed white box specifications to multiple open networks initiatives, and its Distributed Disaggregated Chassis (DDC) model was also adopted by the Facebook-led Open Compute Platform (OCP).
One of the suppliers supporting DDC is DriveNets, whose customers buy white boxes directly from their manufacturers at cost and then pay for DriveNets’ networking software licence separately, rather than on a per-port or per-box basis. This disaggregated core routing software is now, at least in part, supporting AT&T’s network backbone, Fuetsch told the recent Open Networking & Edge Summit.
The five-year-old start-up offers Network Cloud software which runs on scalable physical clusters ranging from 4Tbps to 768Tbps, acting as a single router entity, so that scaling can be done rapidly.
One year after the DDC specifications were submitted to the OCP, the software is fully robust, said the CTO, running on Broadcom’s Jericho2 system-on-chip (SoC), and able to “gracefully scale from 4Tbps to 192Tbps”. He added: “We have now deployed a next generation IP MPLS core routing platform into our production network based on this open software.”
DriveNets is providing the network operating system for that core use case and traffic engineering features for MPLS transport. The whole core routing hardware and software stack has been rewritten from scratch to support containers and microservices, which will handle the huge array of workloads for specific router functions.
The vendor’s CEO, Ido Susan, told SDxCentral: “You find yourself with multi workloads sharing the same chip and simple database, but all the components of the software of the routing function are separated — database, control, and the management orchestration.” The data plane functions run on white boxes and the control plane on x86 servers. AT&T has deployed 192 white boxes from Ufispace.
Fuetsch said the simplified network enabled the scalability and flexibility to respond to major events, even the effect of the Covid-19 pandemic on working habits – having supported WiFi Calling via a virtualized platform and open automation, he said AT&T’s network was able to cope with a peak of 105% increase in usage of WiFi Calling, with new capacity able to be added within hours.
Fuetsch also hinted at more use of public clouds in future, even for key network functions. “As we’ve watched the public cloud grow, and they’ve been growing leaps and bounds, these clouds are not just scaling, they’re also getting much much more capable,” he said.
AT&T has already adopted a public cloud-first strategy for IT workloads over the coming few years but Fuetsch added: “We’re finding the cloud itself is really good at transactional things that are going on, but it’s not necessarily the best at moving large tonnage of bits and bytes and that’s basically the business we’re in. However, he sees tht changing too as the webscalers become more interested in supporting telcos and optimizing their cloud infrastructure to support the specific requirements of carrier networks.
The CTO said AT&T would gain economies of scale from the public cloud, plus agility and “more exposure to these fast-growing developer ecosystem and toolsets that these cloud players bring to the table”. AT&T already has a close alliance with Microsoft, which recently launched Azure for Operators, but also works with Google, AWS and IBM.