Light Reading
Why the metro network may become the sweet spot for cable operators to leverage SDN.

Going All IP

John Holobinko
3/24/2014
100%
0%

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
craigleddy
50%
50%
craigleddy,
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

 

 
t.bogataj
50%
50%
t.bogataj,
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 :)

T.
More Blogs from Column
Don't let new technologies and whizz-bang gadgets keep you from respecting those speaking to you and giving them the full attention they deserve.
Defining SDN realistically will help carriers cut through the hype, says Sunil Khandekar, CEO of Alcatel-Lucent's Nuage Networks.
They can go from also-rans to leaders -- if they don't mess up.
The benefits of SDN are hard to grasp because they're so big. But NFV provides a nice, finite-value proposition.
Intensive end-to-end test and measurement is essential to ensure the smooth rollout of new services like VoLTE.
Flash Poll
LRTV Custom TV
VeEX – Live from the Show

8|21|14   |   5:58   |   (0) comments


An overview of VeEX Test and Measurement solutions including TX300S multi-service test set with VeExpress cloud-based management system, UX400 universal modular platform supporting 100G testing, and the redesigned RXT modular platform.
LRTV Custom TV
Transitioning CE 2.0 Networks Into the SDN & NFV Era With Telco Systems

8|19|14   |   5:19   |   (0) comments


Telco Systems' Ariel Efrati (CEO) and Moshe Shimon (VP of Product Management) discuss virtualization and how the company's new Open Metro Edge solution utilizes the SDN and NFV concepts to accelerate and orchestrate service delivery through its innovative product portfolio and software applications.
LRTV Custom TV
NFV Myths: Is NFV Still Several Years Away?

8|11|14   |   1:13   |   (0) comments


Some say that NFV (network functions virtualization) is still several years away from being implemented on mobile operator networks. This isn't the case. Operators can get started on their paths to NFV now, as this short video from Skyfire shows.
LRTV Custom TV
A New Security Paradigm in SDN/NFV

7|28|14   |   02:54   |   (0) comments


Paul Shaneck, Global Director Network Solutions for Symantec, discusses the evolving virtualized network, explaining how Symantec is leading the security discussion as it relates to SDN and NFV, and helping to ensure the network is protected and compliant.
LRTV Documentaries
Sprint's Network Evolution

7|24|14   |   14:59   |   (0) comments


Sprint's Jay Bluhm gives a keynote speech at the Big Telecom Event (BTE) about Sprint's network and services evolution strategy, including Spark.
LRTV Documentaries
BTE Keynote: The Software-Defined Operator

7|24|14   |   18:43   |   (1) comment


Deutsche Telekom's Axel Clauberg explains the concept of the software-defined operator to the Big Telecom Event (BTE) crowd.
Light Reedy
Numbers Are In: LR's 2014 Salary Survey

7|24|14   |   1:25   |   (7) comments


Our fourth annual Salary Survey paints a picture of who's hiring, firing, earning, and yearning for a change in the telecom industry.
LRTV Custom TV
Driving the Network Transformation

7|23|14   |   4:29   |   (0) comments


Intel's Sandra Rivera discusses network transformation and how Intel technologies, programs, and standards body efforts have helped the industry migration to SDN and NFV.
LRTV Custom TV
Distributed NFV-Based Business Services by RAD

7|18|14   |   5:38   |   (0) comments


With the ETSI-approved Distributed NFV PoC running in the background, RAD's CEO, Dror Bin, talks about why D-NFV makes compelling sense for service providers, and about the dollars and cents RAD is putting behind D-NFV.
LRTV Custom TV
MRV Accelerating Packet Optical Convergence

7|15|14   |   6:06   |   (0) comments


Giving you network insight to make your network smarter.
LRTV Custom TV
NFV-Enabled Ethernet for Generating New Revenues

7|15|14   |   5:49   |   (0) comments


Cyan's Planet Orchestrate allows service providers and their end-customers to activate software-based capabilities such as firewalls and encryption on top of existing Ethernet services in just minutes.
LRTV Custom TV
Symkloud NVF-Ready Video Transcoding, Big Data

7|9|14   |   3:41   |   (0) comments


Kontron and ISV partner Vantrix demonstrate high-performance video transcoding and data analytic solutions on same 2U standard platform that is ready for SDN and NFV deployments made by mobile, cable and cloud operators.
Upcoming Live Events!!
September 16, 2014, Santa Clara, CA
September 16, 2014, Santa Clara, CA
September 23, 2014, Denver, CO
October 29, 2014, New York City
November 6, 2014, Santa Clara
November 11, 2014, Atlanta, GA
December 9-10, 2014, Reykjavik, Iceland
June 9-10, 2015, Chicago, IL
Infographics
Today's Cartoon
Hot Topics
Level 3 Does Big Data Differently
Carol Wilson, Editor-at-large, 8/21/2014
Comcast Streams Back to School
Mari Silbey, Independent Technology Editor, 8/21/2014
Sprint Drops Prices, But Also Speeds?
Sarah Reedy, Senior Editor, 8/21/2014
Line-Powered Phone Lines: A Hot Topic Again
Carol Wilson, Editor-at-large, 8/20/2014
A New Verizon App Store? Say It Ain't So
Sarah Reedy, Senior Editor, 8/20/2014
Like Us on Facebook
Twitter Feed