Comcast: We'll take an incremental approach to deploying 100G

NEW ORLEANS -- Comcast (NASDAQ: CMCSA) is hot on the trail of incorporating 100G into its network, but it is taking a realistic approach to getting there.

Today, the service provider has a multi-tiered network topology that includes a fiber network, transport network and a service layer topology.

Speaking during the SCTE CableTec expo event, Mannan Venkatesan, senior principal network engineer for Comcast, said this multi-tiered network architecture creates a number of issues, particularly in getting its teams to communicate with one another about issues and new service rollouts.

"The problem with these three different topologies is that you different teams designing, building and managing these topologies," Venkatesan said. "To make each topology simple, you add a 10G link between two different sites and you're adding a lambda over multiple transport rings from A to Z using the ROADM technology."

Another issue is adding capacity to each layer of its network. Up until now, Comcast had been adding various 10G rings between each layer as capacity needs have increased.

"When you add long-haul lambdas or transport that means you're adding more issues to every fiber path," Venkatesan said. "That means if you take a single fiber cut it could impact multiple IP flows and your customer flows."

Having deployed 10G optical for over ten years, Comcast can apply those best practices to deploying 100G.

"We are at a critical migration point for a couple of reasons," Venkatesan said. "One reason is we're going to 10G to 100G and 10G links carried us for the last 10 years, but we have learned a lot of lessons learned from those deployments and we can use those lessons learned towards the 100G deployments to get the most lifespan of the 100G deployments."

As it migrates from 10G to 100G, Comcast is also moving towards implementing SDN. Venkatesan said as it implements SDN with 100G "you have to have simple underlying topologies, meaning the transport and the IP layer."

Both of these transitions will be done in a phased approach that takes into consideration all network layers.

"We're taking a phased approach for our 10G to 100G migration," Venkatesan said. 

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This article was updated on Oct. 16 with additional information from Comcast.