The slowly evolving WAN

Network World - We use the phrase cloud networking to refer to the functionality that has to be in the network and in the management of the network in order to support cloud computing. We are going to use this newsletter to discuss how the lack of innovation in the WAN leads to challenges relative to supporting cloud computing.

The modern WAN got its start in 1969 with the deployment of ARPANET which was the precursor to today's Internet. The technology used to build the Internet began to be commercialized in the late 1970s with the development of X.25-based packet switched networks.

In addition to the continued evolution of the Internet, the 20-year period that began in 1985 saw the deployment of four distinct generations of enterprise-focused WAN technologies. For example, in the mid to late 1980s, it became common for enterprise IT organizations to deploy integrated TDM-based WANs to carry both voice and data traffic. In the early 1990s, IT organizations began to deploy Frame Relay-based WANs. In the mid to late 1990s, some IT organizations replaced their Frame Relay-based WANs with WANs based on ATM (Asynchronous Transfer Mode) technology. In the 2000s, many IT organizations replaced their Frame Relay or ATM-based WANs with WANs based on MPLS. Cost savings was the primary factor that drove the adoption of each of the four generations of WAN technologies. The cost savings, however, were very modest when compared with the price performance improvements that local area networking experienced over the same time frame.

However, in contrast to the volatility of this 20-year period, today the WAN is relatively staid. In particular, today there is not a new generation of WAN technology in development. Relative to the deployment of new WAN services what sometimes happens in the current environment is that variations are made to existing WAN technologies and services. An example of that phenomenon is Virtual Private LAN Service (VPLS). Within VPLS an Ethernet frame is encapsulated inside of MPLS. While creating variations on existing services can result in significant benefits, it does not produce fundamentally new WAN services.

One of the conclusions that can be drawn from the last few newsletters is that after a long staid period, data center LANs are highly dynamic. As a result, IT organizations that are adopting private cloud computing and hence are implementing technologies such as server virtualization, have a wide range of new technologies to use to respond to the challenges. In contrast, IT organizations that are adopting cloud computing don't have any fundamentally new WAN technology that they can leverage to respond to the associated challenges. In order to successfully support cloud computing, IT organizations are going to have to get very creative in their use of WAN services. We will come back to this topic repeatedly over the next several months.

Jim recently completed an in-depth report on cloud networking. Given its length, we will be publishing it over the next several weeks in five installments. We will also publish a complete copy of the report. The first two documents have already been published.

Read more about lans & wans in Network World's LANs & WANs section.

Steve Taylor is president of Distributed Networking Associates and publisher/editor-in-chief of Webtorials. Jim Metzler is vice president of Ashton, Metzler & Associates.