Source : Free On-Line Dictionary of Computing

Abstract Syntax Notation 1
     
         (ASN.1, X.208, X.680) An
        {ISO}/{ITU-T} {standard} for transmitting structured {data} on
        {networks}, originally defined in 1984 as part of {CCITT
        X.409} '84.  ASN.1 moved to its own standard, X.208, in 1998
        due to wide applicability.  The substantially revised 1995
        version is covered by the X.680 series.
     
        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 {BER} (Basic Encoding Rules - X.209), {CER}
        (Canonical Encoding Rules), {DER} (Distinguished Encoding
        Rules), and {PER} (Packed Encoding Rules).
     
        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.
     
        {OSI} {Application layer} {protocols} such as {X.400} {MHS}
        {electronic mail}, {X.500} directory services and {SNMP} use
        ASN.1 to describe the {PDU}s they exchange.
     
        Documents describing the ASN.1 notations: {ITU-T} Rec. X.680,
        {ISO} 8824-1; {ITU-T} Rec. X.681, {ISO} 8824-2; {ITU-T}
        Rec. X.682, {ISO} 8824-3; {ITU-T} Rec. X.683, {ISO} 8824-4
     
        Documents describing the ASN.1 encoding rules: {ITU-T}
        Rec. X.690, {ISO} 8825-1; {ITU-T} Rec. X.691, {ISO} 8825-2.
     
        [M. Sample et al, "Implementing Efficient Encoders and
        Decoders for Network Data Representations", IEEE Infocom 93
        Proc, v.3, pp. 1143-1153, Mar 1993.  Available from Logica,
        UK].
     
        See also {snacc}.
     
        (2000-10-20)