Abstract Syntax Notation One (ASN.1) is a standard for describing structured data. Combined with a standard for encoding this data, such as BasicEncodingRules (BER), DistinguishedEncodingRules (DER), CanonicalEncodingRules (CER), or PackingEncodingRules (PER), it can serve as one of the AlternativesToXml.
Overview of ASN.1: http://www.oss.com/asn1/overview.html
Summary with examples of ASN.1 and BER: http://support.microsoft.com/kb/252648/en-us
ASN.1 with BER is used as the basis for SimpleNetworkManagementProtocol (SNMP) and MessageHandlingServices (MHS), for example.
A variety of data encoding standards for transmission of data defined by an ASN.1 structure:
- BER
- (BasicEncodingRules) "was created in the early 1980s and is used in a wide range of applications, such as Simple Network Management Protocol (SNMP) for management of the Internet; Message Handling Services (MHS) for exchange of electronic mail and TSAPI for control of telephone/computer interactions."
- DER
- (DistinguishedEncodingRules) specialized high-security form of BER
- CER
- (CanonicalEncodingRules) large encrypted messages (and incremental parsing -- like SAX, for XML)
- PER
- (PackingEncodingRules) "faster and more compact encodings than BER. PER is used in applications that are bandwidth or CPU starved, such as air traffic control and audiovisual telecommunications."
- XER
- (XML Encoding Rules) ASN.1 in XML.
- E-XER
- "(Extended XML Encoding Rules) [...] ASN.1 an XML schema notation as powerful as XSD, with the simplicity of ASN.1."