Many of today's packet-based networks rely on Quality of Service (QoS) to insure timely delivery of delay-sensitive traffic. QoS only works if the network can easily identify high-priority packets. What we're seeing with SOA's ascendancy is the eventual obsolescence of QoS as a viable networking technique. (There is only one way that QoS could work with a proliferation of SOA-based applications: deep packet inspection, which has significant performance, cost, security, and application transparency issues.)

Mission-Critical WANs
SOA enhances business agility by allowing quicker deployment of new and improved business processes, and applications development is more economical with SOA. Thus, businesses will be deploying more applications. Since SOA-enabled applications will tend to be for business agility, those new applications will usually be mission critical. And as we've discovered, SOA-enabled applications are very dependent upon the wide area network (WAN). Hence, the WAN is becoming more mission critical.

With this increasing adoption of SOA, it's no surprise that we're seeing more businesses and government agencies interested in carrier-grade network equipment. Some network characteristics that are in increasing demand by enterprises are:

• More sensitivity to network downtime. As businesses deploy mission-critical, SOA-based applications, their cost of network downtime can exceed $1 million/hour. They need high-availability network solutions that have proven themselves in production environments with five and six 9s availability. (Bear in mind that five 9s equate to five minutes of downtime every year, and six 9s equate to 31 seconds per year.)
• Applications transparency. Business agility is enhanced when you don't have to tune and debug your applications for the network. Some organizations spend upwards of 40 percent of their IT budget on tuning and debugging applications - well in excess of what they spend on networks. Moreover, tuning and debugging can be a constant chore if the network is not applications transparent. Most organizations experience a constant stream of version updates, bug fixes, service packs from their operating system, and middleware and application software vendors. Having to retune and debug for an applications-aware network with all of those software changes can easily become overwhelming.
• Low latency. Just as carriers have learned to transport traffic at the lowest possible layer, businesses and government agencies are learning that layer 1 and 2 solutions work best. They introduce the least amount of network delay and are best for time-sensitive applications.
• Flexibility, adaptability, and scalability. For increased business agility, organizations must embrace constantly changing business processes. Yet they need their capital equipment (which networking products are) to be useful throughout their expected life - at least until they're fully depreciated. This is a daunting task, with ever-changing network requirements. The only viable solution is to employ software-configurable networking products.

Summary
A critical mass has been created that is finally realizing the promised wave of distributed computing applications. This wave of distributed computing will be based on SOA, and will have profound impacts on the wide-area networks of businesses and government agencies. Exponential traffic growth can be expected, coupled with significant networking challenges: more delay sensitivity, less predictable traffic patterns, and increased difficulty in identifying higher-priority traffic.

For businesses and government agencies, it is becoming increasingly important for them to solve these WAN challenges. SOA-based applications are increasing their reliance upon the network. They would do best to find WAN solutions that are highly available, applications transparent, flexible, adaptable, scalable, and with low latency. Fortunately, these carrier-grade network solutions are now available to enterprises.