Fast Infoset (or FI) specifies a binary encoding format for the XML Information Set (XML Infoset) as an alternative to the XML document format. It aims to provide more efficient serialization than the text-based XML format.
One can think of FI as gzip for XML, though FI aims to optimize both document size and processing performance, whereas gzip optimizes only the size. While the original formatting is lost, no information is lost in the conversion from XML to FI and back to XML.
The Fast Infoset specification is defined by both the ITU-T and the ISO standards bodies. FI is officially named ITU-T Rec. X.891 and ISO/IEC 24824-1 (Fast Infoset), respectively. However, it is commonly referred to by the name Fast Infoset. The standard was approved by ITU-T on May 14, 2005. It was published by ISO on May 4, 2007.
The Fast Infoset standard can be downloaded for free from the ITU website at . There are no intellectual property restrictions on its implementation and use.
A common misconception is that FI requires ASN.1 tool support. Although the formal specification uses ASN.1 formalisms, ASN.1 tools are not required by implementations.
A Java implementation of the FI specification is available as part of the GlassFish project. The library is open source and is distributed under the terms of the Apache License 2.0. Several projects use this implementation, including the reference implementation for JAX-RPC and JAX-WS used in JWSDP.
In addition to a significant reduction in document size of Fast Infoset with respect to standard XML 1.0, SAX-type parsing performance of Fast Infoset is much greater than parsing performance of XML 1.0. Typical increases in parsing speed observed for the reference Java implementation are a factor of 10 compared to Java Xerces, and a factor of 4 compared to the Piccolo driver (one of the fastest Java-based XML parsers). However, the parsing performance building DOM (needed for doing transformation and repetitive random access) remains a challenge.
Portable Devices - With mobile devices typically having access to low bandwidth data connections, and have slower CPUs. This can make Fast Infoset a better choice, lowering both data transmission and data processing times.
Persisting Large Volumes of Data - When persisting XML either to file or a database, the volume of data your system produces can often get out of hand. This has a number of detrimental effects, the access times go up as you're reading more data, CPU load goes up as XML data takes more effort to process, and your storage costs go up. By persisting your XML data in Fast Infoset format, you can reduce your data volume by up to 80 percent.
Passing XML via the internet - As soon as an application starts passing information over the internet, one of the main bottlenecks is bandwidth. If you send reasonable chunks of data, this bottleneck can seriously degrade the performance of your client applications and limit your server's ability to process requests. By reducing the amount of data moving across the internet, you can reduce the time it takes a message to be sent or received, while increasing the number of transactions your server can process per hour.
- Free public download of the Fast Infoset standard
- Fast Infoset page at the ASN.1 site
- Examples of encoding XML infosets as Fast Infoset documents
- FI project home page
- FastInfoset.NET home page
- OSS Fast Infoset Tools page
- C# and C++ Fast Infoset implementationfr:Fast Infoset
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