ASN.1
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Embedded PDV

In 1994, Embedded PDV was created to carry any values, whether or not it is defined in ASN.1. This type has the ability to identify the type and the transfer syntax for the value being carried. ASN.1 has an associated type which must be referenced to create an Embedded PDV type.

X.680 contains the following definiton for the EMBEDDED PDV type:

EmbeddedPDV ::= [UNIVERSAL 11] IMPLICIT SEQUENCE {
identification CHOICE {
  syntaxes SEQUENCE {
    abstract OBJECT IDENTIFIER,
	 transfer OBJECT IDENTIFIER }
	 -- Abstract and transfer syntax object identifiers --,
	 syntax OBJECT IDENTIFIER
	 -- A single object identifier for identification of the abstract
	 -- and transfer syntaxes --,
	 presentation-context-id INTEGER
	 -- (Applicable only to OSI environments)
	 -- The negotiated OSI presentation context identifies the
	 -- abstract and transfer syntaxes --,
	 context-negotiation SEQUENCE {
		presentation-context-id INTEGER,
		transfer-syntax OBJECT IDENTIFIER }
	 --(Applicable only to OSI environments)
	 -- Context-negotiation in progress, presentation-context-id
	 -- identifies only the abstract syntax
	 -- so the transfer syntax shall be specified --,
	 transfer-syntax OBJECT IDENTIFIER
	 -- The type of the value (for example, specification that it is
	 -- the value of an ASN.1 type)
	 -- is fixed by the application designer (and hence known to both
	 -- sender and receiver). This
	 -- case is provided primarily to support
	 -- selective-field-encryption (or other encoding
	 -- transformations) of an ASN.1	type --,
	 fixed NULL
	 -- The data value is the value of a fixed ASN.1 type (and hence
	 -- known to both sender
	 -- and receiver) --
  },
  data-value-descriptor ObjectDescriptor OPTIONAL
  -- This provides human-readable identification of the class of the
  -- value --,
  data-value OCTET STRING }
( WITH COMPONENTS {
       ... ,
		data-value-descriptor ABSENT } )
		

This site was developed from: Computer Networks and Open Systems An Application Development Perspective by Lillian N. Cassel Richard H. Austing Jones & Bartlett Publisher ISBN 0-7637-1122-5

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