AT&T's Paradise: 75% of telco's MPLS tunnel data traffic now under SDN control

AT&T's use of software-defined networking (SDN) is paying off in spades. To wit: AT&T now has 75% of the data traffic running through its multiprotocol label switching (MPLS) tunnels under SDN control.

Having the MPLS tunnels under the auspices of an SDN controller is a big deal for AT&T, according to AT&T's Mike Paradise.

"From my perspective, the work we've done to put AT&T in a position to have a network that software controls, which allows us to react to customer demand and to do this in a more real time manner, is really a big darn deal," said Paradise, vice president of network cloud and infrastructure operations.

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AT&T started its SDN journey in 2014. Under the leadership of John Donovan, who is set to retire at the end of the month, AT&T fully embraced SDN early on. While the first phase of SDN emphasized the capex and opex savings that SDN could enable, SDN has evolved both within networks and customer-facing applications.

MPLS traffic engineering is used inside of networks to establish logical paths over a core network in order to provide tunnels between end points. Paradise said the traffic within those tunnels was previously static.

"So, you have to go into the production network, and you have to define those end points," he said. "So, you go into the routers, the core infrastructure, to set up prescriptive paths between endpoints, and map your traffic accordingly.

"What we've done here, which is really exciting, is that we've been able to take a network controller, and be able to ingest the topology information that changes within our core network into the controller, and couple that with an optical layer that connects all this stuff together. It's a controller that's able to manipulate the optical paths, and then be able to bring that into one place where we have the ability to then control that core backbone traffic in a centralized manner, and couple it with our optical technology."

Paradise said that AT&T largely developed the SDN controller that pulls in data from the optical network and the Layer 3 network. The controller is then able to manipulate all of that data in order to provide greater visibility into potential network problems via a single interface. Layer 1, which includes the physical network components such as network interface cards, and Layer 3, which is the network itself, are integrated, which allows AT&T to spot potential problems before they happen and re-route around anomalies to avod service disruptions.

Paradise said AT&T moved its MPLS traffic under the SDN network controller earlier this year.

"Then we put that into what we would call our 'first field applications, and they are now able to use it for operational use, so it's been a bit of a journey," Paradise said. "Sometime next year, we'll be close to that 100% mark. There could be some outliers here and there. I'm not all that worried about it. But the whole point is that if we get all of our U.S. core inner city traffic pulled together on this, it will allow us the flexibility that we're already realizing now."

Thanks to the continued growth in bandwidth consumption, due to video, IoT, edge computing and, eventually, 5G, Paradise said the SDN control of the MPLS tunnel traffic in the core network puts AT&T in a better position react to customer demands.  

"Our edge computing and the 5G deployments that we'll be doing is all going to be supported on this network," he said. "It's on our core network that's SDN controlled. By us taking advantage of the capabilities of the SDN controller, being able to couple that with real time optical provisioning and bandwidth provisioning, it allows us to be in a really good position to react to the demands that network cloud, or edge cloud, or the 5G services that we'll be putting on our core network.

"I've been doing this a long time, and to get at this point is truly exciting."