CenturyLink is applying the Central Office Re-architected as a Datacenter (CORD) design to improve its traditional copper-based DSL services, an effort that it says can reduce operational costs and enhance broadband service activation times.
CORD combines NFV and SDN-based software to improve elasticity and bring data center economics and cloud agility to the telco’s CO.
While the CORD concept has been touted by fellow telco AT&T to apply in PON-based fiber networks, Adam Dunstan, VP of SDN/NFV engineering for CenturyLink, told FierceTelecom it is finding similar value in applying the design to DSL networks as part of a broader effort to migrate to a software-based network architecture.
“A lot of the previous talk around CORD in fixed line access has been around GPON, but we have done this for DSL,” Dunstan said. “We see CORD as a key part of our modernization program and part of getting a unified access infrastructure.”
Dunstan said CORD will give CenturyLink a common architecture for any type of last-mile network, whether that’s copper-based DSL or fiber-based GPON.
“When go and roll out DSL services, we have a certain bill of materials, which is quite different than the bill of material for equipment when we roll out GPON services,” Dunstan said. “As we move towards this style of architecture where we’re using white box switches and services, we end up with a uniform bill of materials irrespective of what access means we use.”
CenturyLink and AT&T are hardly alone in adopting CORD. IHS found in its latest Routing, NFV, and Packet-Optical Strategies Global Service Provider Survey that 70% of respondents plan to deploy CORD in their smart COs.
A common architecture
This is not a silo system where CenturyLink is going to implement a CORD system for each part of its network.
Because CORD enables CenturyLink to have a platform for all of its services, the service provider can also use the architecture to satisfy other partners of the network besides broadband.
“Its real value is not in having a CORD system for GPON and another CORD system for DSL, but rather having a uniform CORD system that has PHY layers out towards our access infrastructures,” Dunstan said.
This latest initiative with CORD is part of a broader effort to fully virtualize its IP core network by the end of 2019.
During its fourth quarter 2016 earnings call in February, CenturyLink told investors that it had implemented SDN and NFV technology into 60% of its major points of presence (POPs) as of the end of 2016.
Reducing cost, increasing reliability
While CenturyLink is one of the three largest U.S.-based broadband operators, the service provider says that the most expensive part of the network is the broadband network gateway (BNG).
The BNG is the access point for subscribers, through which they connect to the broadband network.
“Clearly, one of the reasons this is a platform we wanted to modernize is the legacy infrastructure is very expensive,” Dunstan said. “BNGs are the second most expensive router you can buy so there’s a reason we were interested in modernizing this part of the network.”
Additionally, when large service providers like CenturyLink started to grow its customer base, it had to deploy larger boxes. These platforms may have been able to support more subscribers, but they became very large and harder to manage and troubleshoot.
“We’ve been on this evolution for a long time and these boxes have become very big,” Dunstan said. “When we do have reliability problems, the impact to us is significant because a lot of customers go out of service.”
By adopting a CORD architecture for its DSL service base, CenturyLink will be able to pinpoint and minimize subscriber downtime when a network event occurs.
“There’s always problems and things will always fail, but we’re going to be able to contain those failures,” Dunstan said. “In the near-term the benefit for our customers we hope to see an improvement in reliability across our footprint and then we’ll look at how to add other services.”