Lisa Pierce: The use of Web services raises WAN issues

Widespread adoption of Web services will likely increase use of the WAN by corporate network customers.

The increase will be due to the very nature of Web services, whereby applications are viewed as a conglomeration of “business services” that communicate with other applications over Internet-based protocols on either an intra-company or inter-company basis. Web services assume seamless integration between software applications and/or business processes, and require connectivity between a wide range of systems, individuals and organizations, often in diverse locations.

Clearly, the appearance of seamlessness requires WAN connectivity that has low network latency and congestion, and high availability. Unfortunately, this does not describe the performance of today’s Internet. Private intranets, or extranets on private IP networks, are feasible alternatives, but prices are high and availability is low compared to the public Internet.

Giga Information Group Inc. expects public and private IP-based network performance to improve. However, we still anticipate that the performance of private IP-based networks will continue to surpass that of the Internet.

The connected nature of Web services in turn implies the following:

– Customer spending on WAN resources will escalate.

– Customers will continue to require the relative price/performance of IP-based WAN services to improve along parameters such as availability, latency and loss. This is particularly critical for business-to-consumer e-marketing, e-commerce and mobile commerce applications that use the Internet.

– Sites that provide Web services applications may require extensive use of alternate WAN providers to achieve near 100 per cent availability. Redundant access will often be required, increasing the cost of Web services.

Recommendations for customers considering Web services include:

– IT should work closely with business units to understand the security and architectural impact of Web services applications on use of the LAN and/or WAN.

– The nature of some applications will require use of the public Internet and will be inadvisable for others.

– Customers should consider using multiple WAN providers to ensure high network availability and performance.

– Because Web services communicate via XML, customers should factor in the potential impact of large XML messages on the WAN. When accounting for XML messages, parsing/deparsing overhead must be added to the transmission time.

– To compensate for WAN latency, many users favour compressing XML, particularly when the CPU overhead required for compression is less than the latency. However, XML compression can slow fast WANs and LANs, which could put pressure on IT managers to increase WAN bandwidth.

– Finally, applications design should be considered, as short XML messages may create more of a WAN headache than fewer larger messages.

Pierce is a research fellow at Giga Information Group Inc. She can be reached at