ASN.1 Structured Data Types

SET(17)

a fixed, unordered set of distinct types, some possibly optional

SET OF(17)

an unordered list of zero or more of the same type

SEQUENCE(16), SEQUENCE OF(16)

a fixed, ordered list of distinct or same types. In ASN.1 based applications such as SNMP, protocol data units (PDUs) (packets?) are commonly defined using this type.

CHOICE(11)

like SET, except more general.

ANY

like CHOICE, except containing a list of anything that can be defined in ASN.1

messageBodyPart ::= CHOICE {
    [0] IMPLICIT asciiText, -- note TAG*
    [1] IMPLICIT telex
    ...etc... }