What the cable operators are planning for NFV and SDN

Cable operators may be quieter than the telecom operators about network functions virtualisation (NFV) and software-defined networking (SDN) but what they are planning is no less ambitious.

Cable operators are working on adding wireless to their fixed access networks using NFV and SDN technologies.

Don Clarke“Cable operators are now every bit as informed about NFV and SDN as the telcos are, but they are not out there talking too much about it,” says Don Clarke, principal architect for network technologies at CableLabs, the R&D organisation serving the cable operators.

Clarke is well placed to comment. While at BT, he initiated the industry collaboration on NFV and edited the original white paper which introduced the NFV concept and outlined the operators’ vision for NFV. 

NFV plans

The cable operators are planning developments by exploiting the Central Office Re-architected as a Datacenter (CORD) initiative being pursued by the wider telecom community. Comcast is one cable operator that has already joined the Open Networking Lab’s (ON.Lab) CORD initiative. The aim is to add a data centre capability to the cable operators’ access network onto which wireless will be added.

CableLabs is investigating adding high-bandwidth wireless to the cable network using small cells, and the role 5G will play. The cable operators use DOCSIS as their broadband access network technology and it is ideally suited for small cells once these become mainstream, says Clarke: “How you overlay wireless on top of that network is probably where there is going to be some significant opportunities in the next few years.”   

One project CableLabs is working on is helping cable operators provision services more efficiently. At present, operators deliver services over several networks: DOCSIS, EPON and in some cases, wireless. CableLabs has been working for a couple of years on simplifying the provisioning process so that the system is agnostic to the underlying networks. “The easiest way to do that is to abstract and virtualize the lower-level functionality; we call that virtual provisioning,” says Clarke.

CableLabs recently published its Virtual Provisioning Interfaces Technical Report on this topic and is developing data models and information models for the various access technologies so that they can be abstracted. The result will be more efficient provisioning of services irrespective of the underlying access technology, says Clarke.  

How you overlay wireless on top of that network is probably where there is going to be some significant opportunities in the next few years   

SNAPS

CableLabs is also looking at how to virtualise functionality cable operators may deploy near the edge of their networks.

“As the cable network evolves to do different things and adds more capabilities, CableLabs is looking at the technology platform that would do that,” says Clarke.

To this aim, CableLabs has created the SDN-NFV Application development Platform and Stack - SNAPS - which it has contributed to the Open Platform for NFV (OPNFV) group, part of the open source management organisation, The Linux Foundation.

SNAPS is a reference platform to be located near the network edge, and possibly at the cable head-end where cable operators deliver video over their networks. The reference platform makes use of the cloud-based operating system, OpenStack, and other open source components such as OpenDaylight, and is being used to instantiate virtual network functions (VNFs) in a real-time dynamic way. “The classic NFV vision,” says Clarke.

CableLabs' Randy Levensalor says one challenge facing cable operators is that, like telcos, they have separate cloud infrastructures for their services and that impacts their bottom line.

Cable operators are now every bit as informed about NFV and SDN as the telcos are, but they are not out there talking too much about it

“You have one [cloud infrastructure] for business services, one for video delivery and one for IT, and you are operationally less efficient when you have those different stacks,” says Levensalor, lead software architect at CableLabs. “With SNAPS, you bring together all the capabilities that are needed in a reference configuration that can be replicated.”

This platform can support local compute with low latency. "We are not able to say much but there is a longer-term vision for that capability that we’ll develop new applications around,” says Clarke.

Challenges and opportunities

The challenges facing cable operators concerning NFV and SDN are the same as those facing the telcos, such as how to orchestrate and manage virtual networks and do it in a way that avoids vendor lock-in.

“The whole industry wants an open ecosystem where we can buy virtual network functions from one vendor and connect them to virtual network functions and other components from different vendors to create an end-to-end platform with the best capabilities at any given time,” says Clarke. 

He also believes that cable operators can move more quickly than telcos because of how they collaborate via CableLabs, their research hub. However, the cable operators' progress is inevitably linked to that of the telcos given they want to use the same SDN and NFV technologies to achieve economies of scale. “So we can’t diverge in the areas that need to be common, but we can move more quickly in areas where the cable network has an inherent advantage, for example in the access network,” says Clarke.