Light Reading

Going All IP

John Holobinko

As networks evolve towards all IP, the ability to commoditize most network functions becomes economically appealing. To understand why the SDN may provide the greatest benefits at the metro network level requires an examination of the network bandwidth and economic challenges in the network core, metro, and access.

"Over-the-top" (OTT) video viewership is rapidly growing and putting great demands on existing network capacity. According to The Ethernet Alliance , network bandwidth is growing at a 59% rate annually. If the future IP network is to deliver virtually all video services, it must be capable of personalizing the video content.

Cable operators have two choices: install customer devices that mimic the functions of the Internet by performing such functions as caching and personalization in the home, or provide these as network functions. Network devices on customer premises will always be challenged by the inability to capitalize on ongoing economic improvements and difficulties in supporting evolving consumer devices, plus cost and deployment times. Velocity -- defined as how fast a provider can react to changing customer behaviors and economics -- will almost always be greater when more functionality is in the network rather than the customer premises.

A major goal of SDN is to both simplify and consolidate network functions, replacing specialized hardware with commodity switches, servers, etc. It enables vertical integration with application control over the network through SDN APIs. Utilizing SDN has the potential to improve service provider velocity and deliver better network economics. But where to implement SDN: the core; the metro edge; the access network?

Today's OTT viewing represents just a very small fraction of total overall consumer video viewing. If all broadcast and unicast video services must traverse the core, then it becomes a major bottleneck, and core capacity would need to expand by two orders or more. Core equipment is expensive, is highly risky to update, and has limited vendors whose equipment primarily uses specialized hardware rather than merchant chips. Thus, it doesn't make economic sense to use the core to deliver the personalized (unicast) services capability required in an all IP network, and therefore it is not the first candidate for SDN.

Access networks must deliver all services to/from residential and business customers. As video traffic explodes, access networks will need to accommodate all of this growth. Twisted pair, coaxial, and multiple fiber technologies are found in the access network, each with its own phy layer and connectivity requirements. Within fiber, there are multiple options such as EPON, GPON, switched Ethernet, and RFoG, for delivering residential and/or business services. It doesn't make sense to create SDN functions that are specialized for each access technology.

Between the core and access networks sits the metro network. 10G Ethernet transport and10G Ethernet switching are becoming cheaper by the minute. A wise sage said, "Never bet against Ethernet". Ethernet switches are simple and easy to make reliable even in outside plant installation, enabling low-cost extension of the metro network. Extending the metro using low-cost Ethernet transport and switching allows the access network to be much dumber and shorter, potentially driving down the cost of adding access capacity.

In this model, the metro becomes the place where the backbone terminates, provides local processing, and then, using switched Ethernet, connects over distances of tens of kilometers to the last few hundred meters of each specialized access network. It becomes logical to put the functions for IP services personalization at the metro network edge. Therefore, the metro network becomes the logical location for SDN functions.

Most network services can be software-defined utilizing commodity servers and switches. By using SDN in the extended metro, existing access networks can potentially become highly agnostic, with service functions instantiated to subscribers via SDN. Everything from DVR-like functionality to MEF-based services can be provided from the metro network.

There will likely be some service functions that require specialized hardware for many years. Examples include deep-packet classification and traffic-shaping functions (such as those that make up part of the cable network's DOCSIS specification), certain forms of encryption, etc. These specialized functions belong at the metro network edge as well.

As services delivery moves to all-IP, all services, whether residential or business, become IP streams, with their primary differences related to bandwidths, tolerable packet losses and latencies. Transport of business services and residential services over a single metro network becomes viable, despite very different QoS requirements. Network expansion costs can be minimized and service velocity maximized.

— John Holobinko, Independent Consultant

(2)  | 
Comment  | 
Print  | 
Newest First  |  Oldest First  |  Threaded View        ADD A COMMENT
User Rank: Blogger
3/25/2014 | 8:21:59 AM
Re: Hitting the nail on the head
Hey John:

Great column. One of the first questions with SDN is defining what the heck it really means. In terms of cable infrastructure, which equipment or functions could be replaced or enhanced by SDN?

The large MSOs are moving toward all-IP delivery and cloud TV. Does SDN require them to change their current game plans or will it become a natural part of their IP migration?      

Hope to see you at LR Cable Next-Gen.

Craig Leddy


User Rank: Light Sabre
3/24/2014 | 1:04:50 PM
Hitting the nail on the head
Congratulations, John, excellent points. (Not really related to "going all IP" though; more relevant for service delivery, related business models & telco benefits.)

Mostly forgotten about, the metro/aggregation segment is actually an area where the telcos will truly be able to see the benefits of SDN in their broadband (i.e. service-delivery) networks.

I agree that this network segment will require specialized hardware rather than COTS servers and switches; but not because of specific service functions (of which you name a few), but for reliability, avaiability and (most of all!) migration scenarios... which represent another neglected aspect of the SDN hype.

It would be interesting to see other opinions. If none appear, we are both right :)

Educational Resources
sponsor supplied content
Educational Resources Archive
More Blogs from Column
The comms industry is rallying to the cause of open, independent interoperability testing.
Data analytics and revenue assurance are growing in strategic importance for the cable industry.
The introduction of IoT applications is supposed to make life easier for homo sapiens. But things are off to a bad start, according to Accedian's Scott Sumner.
Comcast CEO Brian Roberts sees wireless in cable's future and only gradual change in TV bundles.
The LPWAN space for IoT is exciting, but there are too many competing technologies leading to choice overload and confusion.
From The Founder
The comms industry is rallying to the cause of open, independent interoperability testing.
Flash Poll
Live Streaming Video
CLOUD / MANAGED SERVICES: Prepping Ethernet for the Cloud
Moderator: Ray LeMaistre Panelists: Jeremy Bye, Leonard Sheahan
LRTV Interviews
BT Updates on Plans

10|2|15   |   03:16   |   (2) comments

Peter Bell, CIO at Openreach, the access network division at UK incumbent BT, provides an update on the operator's trials and how Openreach is planning to deploy the broadband technology in its street cabinets.
Telecom Innovators Video Showcase
Sonus Shakes Up SD-WAN

10|2|15   |   7:22   |   (0) comments

Sonus CTO Kevin Riley sat down with Light Reading to discuss the trajectory of the company, its SDN ambitions and why Sonus is taking a market-disruptive approve to SD-WAN.
LRTV Interviews
CityFibre's Gigabit Vision

10|1|15   |   03:18   |   (1) comment

Mark Collins, director of Strategy & Public Affairs at competitive UK city network operator CityFibre, talks about his company's plans to help build Gigabit Cities.
Telecom Innovators Video Showcase
Automate, Scale & Create With Juniper's vCPE Solution

10|1|15   |   6:34   |   (0) comments

Join Kireeti Kompella, Juniper Networks CTO, and Steve Saunders, Light Reading Founder and CEO, as they discuss Juniper Networks' approach to NFV showcased with a turnkey vCPE solution, which demonstrates how service providers can use automation to rapidly deploy services.
LRTV Interviews
Gigabit Europe: Day 1 Takeaways

9|29|15   |   05:47   |   (5) comments

Light Reading's Ray Le Maistre and Iain Morris sup a beer and discuss some of the key takeaways from the first day of Gigabit Europe 2015.
LRTV Interviews
Gigabit in Europe

9|29|15   |   04:24   |   (0) comments

At the Gigabit Europe 2015 event in Munich, Heavy Reading's Graham Finnie talks about the availability of gigabit broadband in Europe.
Women in Comms Introduction Videos
AT&T's Band of Women

9|28|15   |   4:36   |   (0) comments

Brooks McCorcle, the president of AT&T's partner solutions divisions and a mathematician by trade, shares stats on AT&T's diversity and advice on how to create your own band of women at work.
Telecom Innovators Video Showcase
Metaswitch's New CEO Martin Lund Discusses His Role

9|25|15   |   11:36   |   (0) comments

Technology industry veteran Martin Lund joins Metaswitch Networks this week as the company's new CEO. In this interview, Lund discusses his new role and the industry's progress with Light Reading CEO Steve Saunders. Lund believes that the industry disruption caused by SDN and NFV is creating opportunities for companies like Metaswitch – network software providers ...
It's All About That App

9|23|15   |   02:15   |   (2) comments

The long-range goal of service providers is to deliver app-specific network performance and that is showing up in technical developments today.
Women in Comms Introduction Videos
Verizon's Healthy Approach to WiC

9|22|15   |   2:30   |   (2) comments

If you think there are too few women in comms, you should see the healthcare industry. Nancy Green, Verizon's healthcare global lead, shares ideas on what we can do about it.
LRTV Huawei Video Resource Center
UBBF 2015 Highlights

9|22|15   |     |   (0) comments

Drilling down deeper into the transformation process will provide network operators with a practical look at building new businesses around a digital virtualized network architecture, and lay out some of the transition steps required, particularly in the struggle to enable more dynamic and focused enterprise network services.
Telecom Innovators Video Showcase
ActiveVideo's Cloud Virtualization Technology

9|22|15   |   7:23   |   (0) comments

ActiveVideo's CMO, Murali Nemani, discusses how virtualized CPE functions can deliver applications from the cloud to various devices at home.
Upcoming Live Events
October 14-15, 2015, New Orleans Ernest N. Morial Convention Center, New Orleans, LA
November 5, 2015, Hilton Santa Clara, Santa Clara, CA
November 17, 2015, Santa Clara, California
December 1, 2015, The Westin Times Square, New York City
December 2, 2015, The Westin Times Square, New York City
All Upcoming Live Events
Communication service providers realize that an ICT transformation is critical to their long-term survival, but most haven't yet committed to making it happen.
Hot Topics
Are Sports Next for Netflix?
Mari Silbey, Senior Editor, Cable/Video, 9/28/2015
Google Gives Huawei a US Device Boost
Dan Jones, Mobile Editor, 9/29/2015
Verizon's Go90 Is Live – Will Anyone Watch?
Mari Silbey, Senior Editor, Cable/Video, 10/1/2015
Following the Bouncing Capex Ball
Carol Wilson, Editor-at-large, 9/29/2015
Good News for NFV Interoperability
Steve Saunders, CEO and founder, Light Reading, 9/29/2015
Like Us on Facebook
Twitter Feed
Webinar Archive
BETWEEN THE CEOs - Executive Interviews
With so many new and exciting communications technologies now under development, it's easy to get caught up in the industry's escalating hype cycle. That's why the ...
Last week saw a big day in the 15-year history of Light Reading when Editor-in-Chief Ray Le Maistre and I were invited to interview the Deputy Chairman and Rotating ...
Cats with Phones
Hold My Calls, Indefinitely Click Here