Backhaul requirements within current wireless networks are largely asymmetrical with most traffic flowing from the core to the handset, according to Mark Gilmour, VP of mobile connectivity solutions at Colt Technology Service. But 5G networks will require more symmetrical backhaul capability.
He said mobile network architectures to date have been fairly straight-forward, comprised of a mobile packet core and a cell site baseband unit at the edge. “Traffic demand is 80% downloaded onto the handset,” said Gilmour. “It’s fairly asymmetric in traffic. It’s almost like a point-to-point.”
But 5G networks, ultimately, will have a different architecture with a core that is fully virtualized and disaggregated. The separation of hardware from software will permit certain parts of the core to be moved toward the edge, if desired. As the 5G core gets distributed, we’re going to see more communication not just from core to edge, but also from edge to core, and from cell site to edge, said Gilmour.
“The backhaul segment may shrink, but instead we’ll have a multi-core environment,” he said. “The control plane will be split out. Now we’ve got this true networking scenario. There’s going to be more traffic flows.”
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He said segment routing will be an important element of 5G backhaul. It enables network operators to create separate classes of network capabilities based on the specific needs of each application or connection. And he also touted Ethernet VPN (EVPN) to give more service-assured paths.
Colt is deploying Cisco’s programmable segment routing and EVPN-based architecture to add greater flexibility to its Colt IQ Network for mobile service providers as they prepare for 5G.
What does Colt have to do with backhaul?
Historically, Colt has offered private enterprise network connections and a number of wholesale services. The company’s Asian and European networks comprise more than 800 data centers and 27,500 fiber-connected buildings that are controlled with the Colt IQ Network. The IQ Network software, based on software-defined networking technology, gives enterprises the ability to boost bandwidth on-demand or quickly provision services at new locations.
In terms of its plans to work with mobile operators on 5G backhaul, Gilmour said it’s about densification — both in terms of cell sites and fiber deployments. Colt is looking at its fiber footprint to resolve demand for 5G. It not only deploys fiber to buildings but also to structures such as lamp posts or bus shelters. This kind of “street furniture” has become relevant for operators as they deploy 5G small cells.
Colt is starting its network preparations for 5G backhaul in regions of Europe where it has its greatest presence. Then it will work on upgrades in Asia and the U.S. Gilmour said, “With a few tweaks, we’ve tailored our Colt IQ Network for mobile operators…..the fact that we have a live SDN network that’s been in place now for three years, that’s the sort of network the mobile industry is trying to build to deliver their own network capabilities. It works very well for dense metro environments.”