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Computerworld - Companies have always backed up their systems and data -- the difference is where they are doing it. Some companies are implementing business continuity and disaster recovery plans by extending their remote storage locations hundreds to thousands of miles away from their primary locations.
Using applications such as database mirroring, remote tape backup, LAN extension and mainframe extension, they use these remotely located systems to continue business operations in the event of primary data center failure.
The transfer of vast amounts of time-sensitive information across large geographic distances for backup or ongoing operations places new requirements on WANs: high throughput, low latency and zero-to-minimal data loss. If your organization is at a loss over latency, this article will explain why and show what your options are.
Web services' impact on the WAN
The bulk of data traveling over the WAN today is storage-related. Within the next few years, however, WANs will also have to support the traffic of a new generation of distributed computing applications, primarily Web services used in service-oriented architectures. Recent surveys indicate that within a year, as much as 90% of all enterprises will deploy applications based on Web services in a significant way. As Web services proliferate within organizations, they will have four major networking effects:

• Intersite traffic volume will grow exponentially. Today, applications are normally executed within a single location. When Web services are used, code is executed at the location of the particular Web service. Since new applications will be created from some original code and a collection of Web services, code execution will be distributed -- typically among multiple sites.


• Low latency will be an increasingly critical network characteristic. When applications execute on a single server, interprocess communications are handled by the server's system bus. When processing is distributed with Web services, such communications are carried over the network. The performance of the network can significantly affect the end user's applications experience.


• Traffic patterns will be less predictable. Web services can be combined in often unpredictable and complex ways. The possible combinations are endless. Network flexibility will be an increasingly important characteristic.


• High-priority packet identification will become increasingly difficult. It will be difficult to ascertain when a particular Web service is being used as part of a mission-critical business process.

Connectivity options
With these WAN challenges, organizations need to revisit their storage and network architectures to meet growing workload requirements.
In the past, organizations reacted to increased traffic volume by prioritizing traffic and adding bandwidth incrementally. While this approach worked when bandwidth needs were growing linearly, this