Fred Kemmerer, Chief Technology Officer for GENBAND, Provides a Detailed Insight

Misunderstandings around the so-called “sunsetting” of the Public Switched Telephone Network (PSTN) create the false impression that the manner and timeframe of the decommissioning of the PSTN has been etched in stone. Reality, however, indicates the opposite. The complexity and magnitude of the undertaking, as well as its implications to thousands of businesses and millions of consumers, suggest that we will experience more of a transition than a “sunset”.

It is important to examine the group which is trying to sort all of this out, the FCC’s Technology Advisory Council (TAC). When you do that, a clearer, more nuanced, and far more interesting picture emerges.

The TAC is a group of industry leaders and experts that provides technical advice to the FCC.  The TAC mandate is to help the FCC develop informed technology policies.  The current TAC was appointed in October 2010, and for the last year it has been studying several important technology issues.  For example, one sub-group is tackling IPv6.  Another is tackling the “Critical Legacy Transition”.  This is where PSTN Sunset is being discussed.  The TAC meetings are broadcast on FCC Live, and fully archived, so you can see exactly what the group has been saying about PSTN Sunset. There are a number of popular myths about PSTN Sunset, but the actual TAC proceedings give us the information to understand the reality behind those myths.

Defining the PSTN

It seems strange to talk about PSTN Sunset, without a clear definition of what is meant by the “PSTN”. Are we talking about shutting down the entire PSTN? If not, then exactly what parts of the “PSTN” are we going to “sunset”? Do we mean (E.164) telephone numbers? Mobile phones use E.164 numbers too. Vonage uses E.164 numbers. Even Skype allows you to use an E.164 number, so that seems unlikely. Is the PSTN the phone that plugs into the wall? Once again, most VoIP services allow you to use standard telephone sets.  Is it the copper wires coming into your home? Those are used for broadband service too, so getting rid of them might not be a good idea either.  You can see where I am going with this.

A close look at the numbers referenced by the TAC would suggest that the definition of the Public Switched Telephony Network has more to do with the installed base of TDM Switch technology in the public network.  That excludes fixed line service that has migrated to VoIP by Carriers and Cable Companies and is being delivered via broadband access.

Also excluded are Internet “Over the Top” VoIP services like Skype and Vonage.   In fact the same thing is going on in mobile networks which also use similar TDM technologies in 2G and 3G voice implementations.  VoLTE will ultimately displace TDM in wireless networks using 3GPP standard SIP based VoIP technology.  Across the industry there’s general agreement that TDM will be retired in the next decade and VoIP will redefine the services scope, cost points, and definition of a new Public Services Network.

Voice and Broadband

There is some truth to the claim that “voice is just another application”. But that does not mean people are not talking and relying on the phone anymore. It certainly does not mean that voice is unimportant. At least it doesn’t look like the FCC views it that way.  In October, the FCC released a Report and Order (R&O) outlining comprehensive reform of the Universal Service Fund (USF) and Intercarrier Compensation (ICC). This document did not propose that USF support be shifted from voice to broadband. Instead, it proposed that the focus be expanded to include voice and broadband.

Earlier this year, the FCC issued a Notice of Proposed Rule Making (NPRM) dealing with outage reporting.  This proposes to expand the existing requirement for voice outage reporting, to include voice, interconnected VoIP, and broadband.  In document after document, the FCC is sending the same message; voice is still a critical universal service, but now, broadband is equally important.

Not a Wireless Only World

The steady growth of wireless is well known. Over half of U.S. broadband subscriptions are mobile. Americans are increasingly cutting the cord, with 30 percent of households only having mobile phone service, according to some industry sources. Are we moving inexorably, and en masse, to a world where all communications needs are provided by wireless networks?  Reading the blogs, you might think so. But this is not what the TAC is proposing. In the September TAC meeting, the head of the Wireless Access sub-team went out of his way to clarify that wireless was one of a range of technologies that would replace legacy TDM networks.

An important TAC objective is to verify that multiple alternative broadband access technologies are available to support the transition from a voice-centric TDM network to an IP-based broadband network.  A closer look at the statistics for mobile substitution in the National Center for Health Statistics1 survey also suggests it is unlikely that everything will move to mobile. True, in some segments of the population, such as unrelated adults living in rented accommodation, wireless substitution is already the norm.

However in other segments, such as families living in a home they own, wireless substitution is much lower - below 20 percent. We see significant geographical differences as well, with affluent, densely populated areas showing the lowest incidence of wireless substitution. Wireless will play an important role, even a critical role, in the transition to a broadband infrastructure. But it is not the only answer. Wired broadband, cable, fiber, satellite and copper all have their own role to play. One size does not fit all!

Keeping Copper

Millions of homes receive their broadband from DSL delivered over copper pairs or from cable systems delivered over copper coax cable.  One of the legal mandates of the FCC is to encourage facilities based competition, and copper plays an important role in this. Over the last ten years we’ve seen fixed line broadband service evolve from dedicated 1Mbit/sec downstream speeds to over 20Mbit/sec today, and the trend continues, driven by increasing end-user demand for content such as High Definition video.

While wireless broadband has also increased in speed, it continues to significantly lag in the ability to deliver dedicated bandwidth for in-home broadband service, especially at competitive price points compared to fixed networks.  Globally, carriers continue to pump significant investment into DSL and Cable access with an expectation that they will deliver competitive broadband services like HD video, telepresence and enhanced messaging, for years to come.  The TAC has said repeatedly that PSTN Sunset does not mean removing all copper pairs from the network.

Wireless vs. Wireline?

Characterizing this as a choice between wireless and wireline, creates a false dichotomy.  Each technology has its strengths. Each technology has its weaknesses. Wireless naturally favors a person-centric perspective; a mobile phone belongs to a person. A landline phone is more naturally associated with a location. For some residential customers, and many business customers, that has advantages. Landlines also do not suffer from reception dead zones and can provide highly reliable network power.  These factors can be important to businesses, to users with disabilities, and to families. In addition, many users, especially business users, view mobile phones as complementary to landline phones. User choice is an important consideration, and the evidence suggests that not everyone will choose wireless all the time.

When it comes to delivering services like voice and multimedia, talking about wireless versus fixed may not be the point.  After all, these are just the access technologies that deliver the service, not the service itself.  The service infrastructure, whether it is based on SIP, IMS, or WebRTC is agnostic to the access technology.

Perhaps what is really required is greater focus on understanding the service capabilities that end-users are looking for – e.g. multimedia not just voice, coordinated family and individual user service, unified communications solutions, ties to social networking etc.  Once that’s done, figuring out how to deliver the service using wireless or fixed line access will be easy.

Misunderstood Statistics

This widely reported statistic comes from a chart shown at the June TAC meeting.  It creates the impression that PSTN lines will continue to decline until 2014 – and then they will go into free fall. The final data point for 2018 is labeled “6% of U.S. population”. But even a casual examination of the chart shows that something is missing. For 2011, the chart shows about 55 million PSTN lines. Another 40 million households only have wireless phone service. That leaves about 35 million households unaccounted for.  Over the top VoIP providers like Vonage barely account for a few million of the missing households, so where are the rest?

The missing customers receive VoIP phone service from a telco digital service like uVerse or FiOS or their cable company. Most people would consider these phones as part of the PSTN, but using a newer technology. The oft-reported chart is not showing falling PSTN lines, but falling TDM lines. It is showing network modernization.

A Continuous Transition

Examining what the FCC TAC is actually saying about PSTN Sunset, and what it does not include under that banner, presents a much clearer picture.  It’s all about technology evolution, and expanding the universal service objectives historically applied to voice. The National Broadband Plan lays this out clearly, defining objectives for both voice and broadband. Step by step, the FCC has been filling in the details of this transition from a voice-centric TDM network to an IP broadband network that will support voice and a range of exciting new services.   The reality behind “PSTN Sunset” is not a discontinuity; it is a continuous transition. It is a transition from the “one size fits all” network of the past, to a network that embraces many technologies; to some extent competitive, but in many ways complementary. It includes cell phones, VoIP, fixed lines, IMS, NGN, Cloud Architectures, IP Centrex, mobile broadband, and even satellite. The list goes on and on.  The transition does not rip out the existing PSTN; it transforms it and builds upon it.

The network in transition will continue providing voice to users who want it, but will also provide video, web collaboration, unified communications and integration with social networks, independent of the underlying access technology. “This is a concept that is well understood in GENBAND. We call it Network Transformation.  GENBAND’s Network Transformation portfolio uniquely enables operators to navigate all stages of the IP evolution process, maximizing the value of existing investment while unleashing the benefits of IP innovation.”

Fred Kemmerer serves as Chief Technology Officer for GENBAND and is responsible for setting the strategic technical direction for the company.