XML appliance

An XML appliance is a separate computer system with deliberately narrow functionality that exchanges XML messages with other computer systems. XML appliances secure, accelerate and route XML so enterprises can cost-effectively realize its full potential for messaging and service-oriented architectures (SOAs). They are designed specifically to be easy to install, configure and manage. While some XML appliances must rely on specialized hardware and software to accelerate the processing of XML messages, others accomplish the same tasks using standards-based hardware and operating systems.

History of XML appliances

The first XML appliances were created by DataPower in 1999 and Forum Systems in 2001, but there were generally two groups of engineers - some who were focused on large volumes of XML transformations and some who were focused on high-speed XML processing and security. The transformation team created specialized software or Application-specific integrated circuits that performed transformations up to 100 times faster than basic software-only solutions. Although there were some early adopters of these systems, it was initially restricted to large e-commerce sites such as Yahoo! and Amazon. The XML processing team created highly optimized appliances that secured and integrated XML across many use cases. Early entrants in XML appliances include vendors such as DataPower (now owned by IBM), Reactivity, Inc. (acquired by CISCO), Forum Systems, Layer 7 Technologies, Vordel, and Sarvega (now owned by Intel).

These two approaches began to converge when a second generation of XML appliances started to appear around 2003, when these devices were used to exchange SOAP XML messages between computers on public networks. These messages required advanced security features such as encryption, digital signatures and denial of service attack prevention. Because the setup and configuration of software-only systems was time consuming, companies could save a great deal of money by using appliances that were pre-packaged with WS-Security standards built in.

Common features of XML appliances

* They can validate XML messages for well-formedness as they enter or exit the appliance
* They include hardware and/or software customized for efficient XML parsing and analysis.
* They have built-in support for many XML standards such as XSLT, XPath, SOAP and WS-Security

Classification of XML appliances

Although the term XML appliance is the most general term to describe these devices, most vendors use alternative terminology that describe more specific functionality of these devices. The following are alternative names used for XML Appliances:

* XML accelerators — are devices that typically use custom hardware or software built on standards-based hardware to accelerate XPath processing. This hardware typically provides a performance boost between 10 and 100 times in the number of messages per second that can be processed.
* Integration appliance — (also known as application routers) are devices that are designed to make the integration of computer systems easier.
* XML security gateways (also known as XML firewalls) are devices that support the WS-Security standards. These appliances typically offload encryption and decryption to specialized hardware devices.
* XML Enabled Networking — an abstraction layer that exists alongside the traditional IP network. This layer addresses the security, incompatibility and latency issues encumbering XML messages, web services and service-oriented architectures (SOAs).

XML appliance vendors

(in alphabetical order)

* Cast Iron Systems [http://www.castironsys.com]
* Cisco AON [http://www.cisco.com/en/US/products/ps6692/Products_Sub_Category_Home.html]
* Citrix Systems
* Dajeil [http://www.dajeil.com/Products.asp]
* DataPower (now owned by IBM), see IBM WebSphere DataPower SOA Appliances
* F5 Networks
* Forum Systems
* InfoTone Communications [http://www.infotone.com]
* Intel SOA Products (formerly Sarvega) [http://www.intel.com/software/soae]
* Layer 7 Technologies [http://www.layer7tech.com]
* Radware http://radware.com/Products/ApplicationDelivery/AppXML/default.aspx
* Reactivity Inc. [http://www.reactivity.com] (acquired by CISCO)
* Solace Systems [http://www.solacesystems.com]
* Sonoa Systems [http://www.sonoasystems.com]
* Stampede Technologies [http://www.stampede.com]
* Vordel
* Xtradyne
* QuickTree (now owned by Citrix Systems)

ee also

* XML
* XSLT
* SOAP
* XML Enabled Networking
* WS-Security
* Apache Axis
* Integration appliance