AT&T to Show Off Next-Gen Central Office

Ray Le Maistre
News Analysis
Ray Le Maistre, Editor-in-Chief
6/15/2015



With its virtualization strategy already well underway, AT&T is now working out how its central office facilities can evolve and become part of its next-generation, new IP network.

The US operator already revealed, at the recent Light Reading Carrier SDN Networks event, how it is working towards the virtualization of its Gigabit Passive Optical Network (GPON) infrastructure and how that plan could also be applied to cable broadband and copper-based broadband (specifically G.fast) deployments. (See AT&T Testing Virtualized GPON.)

Now AT&T Inc. (NYSE: T) is set this week to take its next step towards the development of a cloud-oriented wide area network by participating in a proof-of-concept called Central Office Re-architected as Data Center (CORD) at the Open Networking Summit (ONS) in Santa Clara, Calif.

The other participants in CORD are chip vendors PMC-Sierra Inc. (Nasdaq: PMCS) and Sckipio Technologies alongside the ONOS project, which is led by ON.Lab . The PoC encompasses central office equipment (GPON and G.fast) and customer premises equipment (CPE).


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Guru Parulkar, co-founder and executive director of ON.Lab, believes AT&T is "reinventing the central office." During a recent conversation with Light Reading he noted that the operator is asking "What if we wanted to reinvent the central office with data center economics, with servers as building blocks?"

So what can ONS attendees expect to see?

The basic idea is that, for a FTTH deployment using GPON, the optical line terminal (OLT) that commonly sits in the central office is compressed into a single rack unit line card, while a variety of applications running over ONOS -- a carrier-grade SDN-enabled operating system -- perform multiple functions, such as authentication. It is a one-size-fits-all approach for consumer, enterprise and wholesale services, "all running on slimmed down, simplified blades," noted Parulkar.

This is a scalable, white box architecture that would compare very favorably with the current central office set-up that involves multiple, single-function boxes, noted the ON.Lab man.

If AT&T is able to develop a commercial, carrier-grade solution it can roll out in its production network, the impact could be enormous: AT&T has thousands of central offices across the US (though at the time of publication the operator was unable to pinpoint exactly how many locations it has).

The virtual OLT "looks like a data center rack," PMC-Sierra's Director of Product Marketing Hamish Dobson told Light Reading recently. The white box hardware is, in essence, a "stackable OLT" with GPON blades that are connected via Ethernet to a top-of-rack switch. This approach, using chipsets that include functions such as traffic management and control processor capabilities, "could also be applied to a stackable DSLAM," noted Dobson.

While PMC-Sierra is supplying OpenFlow-enabled GPON chipsets for a virtual OLT, Sckipio is providing the PoC with OpenFlow-enabled G.fast chipsets to show how high-speed broadband services over short copper tails could also be incorporated into a virtualized network topology.

ONOS, OpenStack (for virtual infrastructure management) and XOS, "an open source service orchestration/management platform built on OpenStack," according to an ON.Lab announcement, provide the management of the virtualized environment. (See ON.Lab Intros Open Source SDN OS.)

The PoC will be of great interest to telcos with central office/local exchange facilities the world over. Telcos are sometimes referred to as "real estate companies that provide communications services," so large are their real estate holdings. Being able to build a more scalable and manageable access network infrastructure and free up a lot of valuable space in central office facilities would create massive economic potential for network operators.

CORD may be at its first stages of development, but the pace of change and implementation in the communications networking sector just now suggests that such gains and efficiencies might not be too many years away, and may soon be having an impact on the balance sheets of the largest Tier 1 operators.

Ray Le Maistre, Circle me on Google+ Follow me on TwitterVisit my LinkedIn profile, Editor-in-Chief, Light Reading

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