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By Salvatore Salamone

November 15, 2002 | DataPower Technology Inc. and Sarvega  Inc. recently introduced network hardware devices designed to more efficiently handle XML data.

“XML is verbose, and handling XML data can strain application servers,” says Danny Briere, CEO of the IT and communications consultancy TeleChoice Inc. For that reason,  these devices can reduce the time it takes to convert XML data into the appropriate format for the application being used. As a network appliance, the hardware device physically resides between the server and the client, freeing the Web or application server from CPU-intensive chores such as handling XML data.  

Neither company could provide a life science customer to offer feedback, but both have customers in other industries that use the hardware devices to speed XML data handling. For example, Hemscott PLC, a London-based business information provider, uses DataPower’s XA35 XML Accelerator product to cut the time it takes customers to download financial information stored in XML format. The XML files containing the financial data were about 500K and the software-based transformation of this data into HTML format took application servers about 20 seconds. The XA35 product reduced the transformation time to 1 second, allowing faster delivery of the content to customers.

Such acceleration could be handy in the life sciences because many databases store genomic sequence and annotation information in the XML format. Using an XML accelerator device shortens the time required to access data by off-loading conversion duties.

Relief from computationally intensive tasks such as XML conversion is common on application servers. For example, companies today frequently use dedicated hardware devices to offload the encryption and decryption tasks associated with using SSL (secure sockets layer) or virtual private networks.

One reason special hardware is desirable for handling XML data is the size of the files involved. Hemscott’s relatively large file size of 500K is indicative of XML data. “With XML, no matter how small the message, you have fixed overhead,” says Charlie McCallan, vice president of product management at BoostWorks Inc., a company that specializes in the Web acceleration software. “A message with a 5 byte payload might have 300 bytes of [XML] description.”

This makes XML data quite different from traditional data stored in common relational database management systems. For example, 1GB of traditional database information might expand to as much as 20GB when XML descriptions and coding are applied, according to the XML and Web services research firm ZapThink LLC.

Beyond Conversion
Most companies that deploy XML hardware devices will likely use them initially to speed conversion for XML data, but the devices have other uses as well. The Sarvega XPE Switch, for instance, combines transformation with intelligent switching. “We make smart decisions based on deep data inspection,” says John Chirapurath, Sarvega’s vice president of marketing.

Content-based routing of information within a life science company is one potential use of intelligent switching. A scientist could submit the results of an experiment to a database where a Sarvega switch, programmed to search through XML descriptors for anything relating to a particular compound, would examine the data packets. If the particular compound of interest is identified in an XML description within the data, the XPE switch could be instructed to notify a manager in another research group that a new experiment has been completed.

Companies generally deploy XML technology in one of two ways.

One mode of operation would be to install an XML acceleration device in what is called a proxy mode. Proxying is commonly used with many Web applications. A Web proxy sits between users and all Web application servers. The proxy device examines all user requests for data or access to an application. The packets passing through the proxy are examined and an action is taken based on a set of rules put in place by the company.

If an XML accelerator is used as a proxy, the XML processing tasks are passed from the application to the accelerator. For example, the XML accelerator could take XML data retrieved by an application and convert them to HTML. 

A second option is to create a closer relationship between the application and the accelerator. DataPower calls this an application co-processor mode. The application that uses XML data is modified to handle conversion tasks, freeing up the application server to handle more simultaneous requests or users. “It’s like having a daughter card for the application server,” says Kieran Taylor, DataPower’s director of product marketing.

XML accelerator products like Sarvega’s and DataPower’s are just starting to come to market, and they don’t come cheap. Pricing depends on a range  of factors, but the  DataPower XA35 starts at $55,000 while Sarvega’s XPE Switch starts at $100,000. For now, life science managers should keep an eye out for other XML accelerators as more are likely to enter the market.


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