Abstract Syntax Notation One - ASN.1 in Transfer

ASN.1 in Transfer

Data generated at various sources of observation need to be transmitted to one or more locations that process it to generate useful results. For example, voluminous signal data collected by a radio telescope from outer space. The system recording the data and the system processing it later may be diverse in nature and may also be from different vendors. As such, a consistent mechanism is needed to record, transmit and be able to read data across such diverse systems.

ASN.1 defines the abstract syntax of information but does not restrict the way the information is encoded. Various ASN.1 encoding rules provide the transfer syntax (a concrete representation) of the data values whose abstract syntax is described in ASN.1.

The standard ASN.1 encoding rules include:

• Basic Encoding Rules (BER)
• Canonical Encoding Rules (CER)
• Distinguished Encoding Rules (DER)
• XML Encoding Rules (XER)
• Packed Encoding Rules (PER)
• Generic String Encoding Rules (GSER)

ASN.1 together with specific ASN.1 encoding rules facilitates the exchange of structured data especially between application programs over networks by describing data structures in a way that is independent of machine architecture and implementation language.

Application layer protocols such as X.400 electronic mail, X.500 and Lightweight Directory Access Protocol (LDAP) directory services, H.323 (VoIP), Kerberos, BACnet and Simple network management protocol (SNMP) use ASN.1 to describe the protocol data units (PDU) they exchange. It is also extensively used in the access and non-access strata of UMTS. There are many other application domains of ASN.1.

A particularly useful new application of ASN.1 is Fast Infoset. Fast Infoset is an international standard that 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.