January 26, 2012

What's Become of WAN Innovation?

We talk constantly about innovation in virtually every area of networking. But what about the WAN? With use of older WAN technologies such as Multi-Protocol Label Switching (MPLS) and frame relay past their growth peaks, are new ones emerging to take their place?

Not really, and here's the situation: The modern WAN got its start in 1969 with the deployment of ARPANET, the precursor to today's Internet. As the Internet continued to evolve to provide universal connectivity, the 20-year period that began in 1985 saw the deployment of four distinct generations of enterprise WAN technologies. These technologies were designed to provide connectivity primarily within the enterprise and between the enterprise and its key contacts (e.g., partners and suppliers).

As a result of all of this innovation in WAN services, many IT organizations' WANs grew to include myriad technologies and services.

Traditional WAN Services Wane

However, as highlighted in the Webtorials 2011 Cloud Networking Report, that situation is changing rapidly. The report contained the results of a survey in which 108 respondents were asked to indicate the extent to which they currently use each of 11 WAN services, including frame relay and asynchronous transfer mode (ATM). Not too long ago, these services were widely deployed. However, more than half the survey respondents have no frame relay in their networks, and almost two thirds have no ATM.

In addition, few IT organizations are increasing - and many are actually decreasing - their use of these technologies. The survey results clearly indicated that the primary WAN services currently used by IT organizations are MPLS, Virtual Private LAN Service (VPLS, a variation of MPLS) and the Internet.

Survey respondents were also asked to forecast any changes in their organizations' use of MPLS, VPLS and the Internet over the next year. The table below shows the percentage of the survey respondents who indicated an increase in the use of those services.

NGTNJan26-3.JPGThe data in the table clearly indicate that, while IT organizations will increase their use of both MPLS and the Internet, they will make a significantly greater increase in their reliance on the Internet.

No Clear MPLS Successor

In contrast to the 20-year period ending in 2005, today there is no fundamentally new generation of WAN technology under development. This means that, given the long time it takes for any new WAN technology to become mainstream, MPLS will have no clear successor in the foreseeable future.

This situation should definitely raise concerns for two reasons. First, the amount of traffic traversing the WAN continues to soar. How will we accommodate it? Second, unlike other components of the IT realm, such as processors and memory, the WAN does not follow Moore's Law (i.e., doubling in performance every 18 months); hence the unit cost of the WAN will just keep rising.

What innovation is occurring today involves variations on existing WAN technologies and services. One example of that phenomenon is VPLS, where an Ethernet frame is encapsulated in MPLS. Future TechNotes will describe some additional emerging WAN service options based on variations in current services - most notably those that make the Internet perform more like MPLS. Will these new services be enough to meet enterprise WAN needs in the coming years? It's just too early to tell.

At the upcoming Interop conference in Las Vegas, I will moderate a session titled "How to Redesign Your WAN" on Wednesday, May 9, 10:15-11:15 a.m. Please attend and learn more about this important topic.


Hi Jim,
Given the huge price difference between Internet and private WAN services and the steadily improving quality if Internet, the 'successor' to MPLS might be an entirely different business model. To enhance Internet connectivity, it is not longer necessary to provide a private backbone; the remaining problems are in the local connections. Many Internet providers already offer 'business' access, with no or lower oversubscription than residential offerings. A service that orchestrates the various local ISP's and provides monitoring of CPE (xVPN boxes) plus backup circuits over mobile networks seems much more attractive.

I am a professor of Southwest jiaotong University, China. I have been working on NGI architecture since 2001 sponsored by Natural Science Foundation of China and published more than 20 papers internationally. My solution to backbone subnetworks of Internet is to reduce the User-data switching platform to a single layer unlike MPLS with an enhancement on top of existing data link layer protocols.


Thanks for writing. I certainly agree with you that given the huge price difference between the Internet and private WAN services combined with the steadily improving quality of the Internet that the Internet is poised to become more of a WAN backbone for a growing number of organizations. I also agree that the quality of the local connections have limited many organizations from making more use of the Internet.

In future TechNotes I will discuss a variety of techniques that can be used to make the Internet as robust of a backbone network as MPLS.

Thanks again for writing.

Hi Jim
In my role as Performance Optimisation Consultant, I am keen to follow this.
The uptake of MPLS here in South Africa is about as significant as most other markets. However, we still operate in a non-deregulated telco environment where all SP ADSL services still terminate on Telkom DSLAM switches, so ADSL reliability and/or aggregation is still more of an issue than elsewhere.
Even so there is the same need here to reduce cost by moving at least some services to ADSL and 3G.


Thanks for your comment. It is interesting to see just how universal is the desire to reduce cost by moving at least some WAN traffic to the Internet. I will definitely come back to that topic in future TechNotes.


Can you please say more about what you mean by "a single layer unlike MPLS with an enhancement on top of existing data link layer protocols"? Thank you!

This comment is posted on behalf of Alan Weissberger.

As most of you know, I've been complaining about the dearth of WAN innovation for almost 10 years now. See the recent IEEE Discussion list posts on Network Infrastructure

The only things I've seen happening are:

1. GPON as a last mile delivery/transport for triple play residential services
2. After 8 years, a mild uptake in carrier Ethernet/business Ethernet/ Ethernet First Mile/EoC, but not the 1G Ethernet over SMF that so many of us expected would take off in 2002- 2003.
3. Re-engineering carrier owned IP-MPLS networks for shared VPN access to Cloud Computing services, e.g. Savvis talked about this at our Oct 2011 meeting
4. 40G/100GE in data centers, aggregated backbone networks, Internet exhanges

But the business customer really has not gotten any new WAN services since Frame Relay in the early 1990s (as a "virtual network" replacement for multipoint private lines). Carriers tried SMDS and ATM WANs but both failed to gain market traction and are now dead.

Check the comments below and let us know what you think?

Again,, here is a guide for WAN service and carrier selection:


And this one written by 2010-2011 NA ComSoc Co-ordinator Gabe Jakobson:


All best

Alan J Weissberger, ScD
Manager of IEEE ComSoc Community web site

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