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⟦d9d00f189⟧ TextFile

    Length: 19842 (0x4d82)
    Types: TextFile
    Names: »a-abstract.tex«

Derivation

└─⟦2d1937cfd⟧ Bits:30007241 EUUGD22: P.P 5.0
    └─⟦35176feda⟧ »EurOpenD22/isode/isode-6.tar.Z« 
        └─⟦de7628f85⟧ 
            └─⟦this⟧ »isode-6.0/doc/practical/a-abstract.tex«

TextFile

%\f

\begin{bwslide}
%\part	{ABSTRACT SYNTAX}\bf
%\end{bwslide}


\f

\begin{bwslide}
\part	{ABSTRACT SYNTAX}\bf

\vskip.5in
\diagram[p]{figureA-26}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {ABSTRACT SYNTAX}

\begin{nrtc}
\item	UTILIZED THROUGHOUT THE UPPER LAYERS
\item	NOT A LAYER ITSELF
\item	IMPORTANT TO UNDERSTANDING REMAINING UPPER LAYERS
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {ABSTRACT SYNTAX\\PURPOSE}

\begin{nrtc}
\item	DEFINES STRUCTURE FOR UNITS OF DATA BEING EXCHANGED
\item	INSURES EQUIVALENT UNDERSTANDING OF DATA ON BOTH ENDS OF A CONNECTION
\item	\underline{BOTTOM LINE}: SEPARATES PROTOCOL STRUCTURE FROM 
			INTERNAL STRUCTURE
\end{nrtc}
\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {ABSTRACT DATA TYPES}
%
%\begin{nrtc}
%\item   REMOTE OPERATIONS ARE A MECHANISM BY WHICH LOOSELY COUPLED SYSTEMS
%        INTERACT
%
%\item   BUT, REMOTE OPERATIONS ARE ONLY ONE PART OF A LARGER PICTURE HOWEVER
%
%\item   THE FUNDAMENTAL CONCEPT IS THAT OF THE \emph{ABSTRACT DATA TYPE}
%\end{nrtc}
%\end{bwslide}


\f

\begin{bwslide}
\ctitle {CHARACTERISTICS}

\begin{nrtc}
\item	GENERALLY HAVE FORMAL DESCRIPTIONS
\item	\underline{BIG ADVANTAGE}: CAN BE HANDLED WITH PROTOCOL ``TOOLS''
\item	THIS WILL BE AN IMPORTANT CONCEPT AS WE PROCEED
\end{nrtc}
\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {DATA REPRESENTATIONS}
%
%\begin{nrtc}
%\item	ABSTRACT
%	\begin{nrtc}
%	\item	TYPES OF DATA DESCRIBED INDEPENDENT OF INTERNAL REPRESENTATION
%	\end{nrtc}
%\item	CONCRETE
%	\begin{nrtc}
%	\item	AN ACTUAL \underline{INTERNAL} DATA INSTANCE 
%			{\em (FORM NOT DEFINED BY OSI)}
%	\end{nrtc}
%\end{nrtc}
%\end{bwslide}


\f

\begin{bwslide}
\ctitle {PROPERTIES OF ABSTRACT DATA TYPES:\\ REPRESENTATION}

\begin{nrtc}
\item   DATA STRUCTURES IN PROGRAMMING LANGUAGES HAVE A \emph{CONCRETE}
        REPRESENTATION
    \begin{nrtc}
    \item       WHICH IS DEFINED BY THE PROGRAMMING LANGUAGE AND THE
                UNDERLYING HARDWARE

    \item       e.g., BYTE-ORDERING, WORD SIZE, etc.
    \end{nrtc}

\item   THE CORRESPONDING ABSTRACT DATA TYPE IS DEFINED IN AN
        IMPLEMENTATION-INDEPENDENT FASHION
    \begin{nrtc}
    \item       TERMED THE \emph{ABSTRACT SYNTAX}
    \end{nrtc}

\item   AN APPLICATION CAN EXPECT THIS TO BEHAVE CONSISTENLY REGARDLESS OF THE
        HARDWARE ON WHICH IT IS RUNNING
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {TRANSFER SYNTAX}

\begin{nrtc}
\item	RULES USED TO MAP BETWEEN
	\begin{nrtc}
	\item	ABSTRACT SYNTAX, and
	\item	``BITS ON THE WIRE''
	\end{nrtc}
\item	USED TO PRODUCE UNAMBIGUOUS REPRESENTATION OF DATA ON A CONNECTION
\item	OVERCOMES DIFFERENCES IN MACHINE ARCHITECTURES FOR COMMUNICATIONS
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {SCENARIO}

\begin{nrtc}
\item	CONCRETE DATA VALUES ARE MAPPED TO ABSTRACT SYNTAX FOR DATA TYPES
\item	TRANSFER SYNTAX IS APPLIED TO THE COMBINED ABSTRACT SYNTAX AND
	THE DATA VALUES
\item	RESULTS IN UNAMBIGUOUS DATA STREAM TO BE TRANSMITTED
	\begin{nrtc}
	\item	CALLED: {\em SERIALIZING}
	\end{nrtc}
\item	{\em REVERSE PROCESS FOR RECEIVED DATA}
\end{nrtc}
\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {PROPERTIES OF ABSTRACT DATA TYPES:\\ OBJECT MODEL}
%
%\begin{nrtc}
%\item   SINCE OPERATIONS INTRODUCE A LEVEL OF INDIRECTION,
%        USING ABSTRACT DATA TYPES RATHER THAN CONCRETE DATA STUCTURES
%        PERMITS ACCESS TO DATA STRUCTURES WITHOUT REGARD TO THEIR ACTUAL
%        IMPLEMENTATION
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {PROPERTIES OF ABSTRACT DATA TYPES:\\ OPERATIONS}
%
%\begin{nrtc}
%\item   ACCESS TO AN ABSTRACT DATA TYPE IS DEFINED BY A SET OF PRIMITIVE
%        ACTIONS
%
%\item   EACH PRIMITIVE ACTION IS TERMED AN \emph{OPERATION}
%
%\item   THIS SET OF OPERATIONS DEFINES THE COMPLETE BEHAVIOR OF AN ABSTRACT
%        DATA TYPE
%\end{nrtc}
%\end{bwslide}


\f

\begin{bwslide}
\ctitle {SYNTAXES}

\begin{nrtc}
\item	{\em ASN.1} IS THE ONLY ABSTRACT SYNTAX DEFINED TODAY
	\begin{nrtc}
	\item	{\em ABSTRACT SYNTAX NOTATION 1}
	\end{nrtc}
\item	{\em BER} IS THE ONLY TRANSFER SYNTAX DEFINED TODAY
	\begin{nrtc}
	\item	{\em BASIC ENCODING RULES}
	\end{nrtc}
%\item	THAT IS, {\em DEFINED IN OSI}
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {ABSTRACT SYNTAX NOTATION ONE (ASN.1)}

\begin{nrtc}
\item	DESCRIPTIVE LANGUAGE USED TO DEFINE DATA TYPES
\item	DEFINES
	\begin{nrtc}
	\item	SET OF PRIMITIVE DATA TYPES
	\item	FACILITY TO CONSTRUCT NEW ELEMENTS
	\end{nrtc}
\item	A FORMAL DESCRIPTION LANGUAGE
	\begin{nrtc}
	\item	HAS A FORMAL GRAMMER
	\end{nrtc}
\item	GRAMMAR IS DYNAMICALLY EXTENTABLE
\item	USED TO SPECIFY NEW PROTOCOLS
	\begin{nrtc}
	\item	INTENDED TO BE ``CLEAR--TO--READ''
	\item	NOT SPECIFIC TO MACHINE--ORIENTED STRUCTURES AND RESTRICTIONS
	\end{nrtc}
\end{nrtc}
\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {ASN.1 IS IMPORTANT}
%
%\begin{nrtc}
%\item	UNDERSTANDING ASN.1 IS A PREREQUISITE TO UNDERSTANDING THE 
%	OSI UPPER LAYERS AND TO BUILDING OSI APPLICATIONS
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {ASPHALT SYNTAX NOTATION ONE}
%
%\em{BECAUSE IT IS NOT CONCRETE}
%
%\end{bwslide}


\f

\begin{bwslide}
\ctitle {BASIC ENCODING RULES (BER)}

\begin{nrtc}
\item	RULES FOR ENCODING ASN.1 VALUES AS STREAMS OF BITS
\item	DEFINES
	\begin{nrtc}
	\item	SMALL SET OF GENERAL ENCODING RULES
	\item	RULES CAN BE APPLIED RECURSIVELY TO ENCODE COMPLEX TYPES
	\end{nrtc}
\item	TAG, LENGTH, VALUE (TLV) ENCODING SCHEME
\item	VERY GENERAL
\item	NOT AS PERFORMANT AS OTHER TECHNOLOGIES
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {BER IS NOT AS IMPORTANT}

\begin{nrtc}
\item	SPECIFICS ARE NOT AS IMPORTANT AS ASN.1
\item	UNDERSTANDING THE CONCEPTS IS IMPORTANT
\item	FEW NEED TO UNDERSTAND THE DETAILS
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {FUTURE SYNTAXES}

\begin{nrtc}
\item	MORE SYNTAXES MAY BE DEFINED IN THE FUTURE
\item	MORE ABSTRACT SYNTAXES:
	\begin{nrtc}
	\item	{\em ASN.2, ASN.3, \ldots ?}
	\end{nrtc}
\item	OTHER TRANSFER SYNTAXES:
	\begin{nrtc}
	\item	COMPRESSION
	\item	ENCRYPTION
	\end{nrtc}
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {ASN.1 NOTATION}

\begin{nrtc}
\item	MODULES GROUP AND NAME RELATED DEFINITIONS:
\begin{quote}\small\begin{verbatim}
<<module>> DEFINITIONS ::=
BEGIN

<<linkage>>

<<declarations>>

END
\end{verbatim}\end{quote}
\item	LINKAGE REFERENCES DECLARATIONS IN OTHER MODULES
\item	DECLARATIONS ARE THE DEFINITIONS FOR THIS MODULE:
	\begin{nrtc}
	\item	TYPES --- DATA STRUCTURES
	\item	VALUES --- INSTANCES OF TYPES
	\item	MACROS --- LANGUAGE EXTENSIONS
	\end{nrtc}
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {EXAMPLE --- MODULE NAME}

\begin{quote}\small\begin{verbatim}
DirectorySystemProtocol {joint-iso-ccitt ds(5) modules(1) dsp(12)}
DEFINITIONS ::=

...
\end{verbatim}\end{quote}
\end{bwslide}

\f

\begin{bwslide}
\ctitle{EXAMPLE --- LINKAGE}

\begin{quote}\small\begin{verbatim}
...

EXPORTS
    directorySystemAC, chainedReadASE, ... ;

IMPORTS
    distributedOperations, directoryAbstractService
        FROM UsefulDefinitions {joint-iso-ccitt ds(5) modules(1) 
                                              usefulDefinitions(0)} ;

...
\end{verbatim}\end{quote}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {DECLARATION CONVENTIONS}

\begin{nrtc}
\item	TYPES
	\begin{nrtc}
	\item	NAMES START WITH UPPERCASE LETTERS
	\begin{quote}\small\begin{verbatim}
	TimeLimit
	\end{verbatim}\end{quote}
	\end{nrtc}
\item	VALUES
	\begin{nrtc}
	\item	NAMES START WITH LOWERCASE LETTERS
	\begin{quote}\small\begin{verbatim}
	actualTimeLimit
	\end{verbatim}\end{quote}
	\end{nrtc}
\item	MACROS
	\begin{nrtc}
	\item	NAMES ARE ALL UPPER CASE
	\begin{quote}\small\begin{verbatim}
	SIGNED
	\end{verbatim}\end{quote}
	\item	APPEAR LIKE OTHER ASN.1 KEYWORDS
	\end{nrtc}
\end{nrtc}
\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {NOTE}
%
%\begin{nrtc}
%\item	TYPES
%	\begin{nrtc}
%	\item	SIMPLE
%	\item	OBJECT IDENTIFIERS
%	\item	CONSTRUCTOR TYPES
%	\item	TAGGED TYPES
%	\item	META TYPES
%	\item	ENCRYPTED
%	\item	EXTERNAL
%	\item	SUBTYPES
%	\end{nrtc}
%\item	VALUES
%	\begin{nrtc}
%	\item	?
%	\end{nrtc}
%\end{nrtc}
%\end{bwslide}


\f

\begin{bwslide}
\ctitle{EXAMPLE --- TYPES \& VALUES}

\begin{quote}\small\begin{verbatim}
Multiple-defined-contexts ::= BOOLEAN

simple Multiple-defined-contexts ::= FALSE -- or TRUE

ContentLength ::= INTEGER

RegistrationMailType ::= 
    INTEGER {
        non-registered-mail (0),
        registered-mail (1),
        registered-mail-to-address-in-person (2)
    }

mymail RegistrationMailType ::=
        registered-mail  -- or 1
\end{verbatim}\end{quote}
\end{bwslide}


\f

\begin{bwslide}
\ctitle{EXAMPLES --- TYPES \& VALUES (cont.)}
\begin{quote}\small\begin{verbatim}
Attribute-Groups ::=
        BITSTRING {
            storage (0), security (1), private (2)
        }

groups Attribute-Groups ::=
        { storage, private }	-- or '101'B
\end{verbatim}\end{quote}
\end{bwslide}


%\f

\begin{bwslide}
%\ctitle{EXAMPLES --- TYPES \& VALUES (cont.)}
%\begin{quote}\small\begin{verbatim}
%Content ::= 
%        OCTET STRING
%
%BilateralInfo ::=
%        ANY
%\end{verbatim}\end{quote}
%\end{bwslide}


\f

\begin{bwslide}
\ctitle{EXAMPLES --- TYPES \& VALUES (cont.)}
\begin{quote}\small\begin{verbatim}
SecurityContext ::=
        SET OF SecurityLabel

MessageDeliveryEnvelope ::=
        SEQUENCE {
            message-delivery-identifier
                MessageDeliveryIdentifier,

            message-delivery-time
                MessageDeliveryTime,

            other-fields
                OtherMessageDeliveryFields
}
\end{verbatim}\end{quote}
\end{bwslide}


%\f

\begin{bwslide}
%\ctitle{EXAMPLES --- TYPES \& VALUES (cont.)}
%\begin{quote}\small\begin{verbatim}
%MessagesWaiting ::=
%        SET {
%                urgent [0]
%                    DeliveryQueue,
%                normal [1]
%                    DeliveryQueue,
%                nonUrgent [2]
%                    DeliveryQueue
%        }
%
%queue MessagesWaiting ::= 
%        {
%            urgent { ... }, normal { ... }, nonUrgent { ... }
%        }
%\end{verbatim}\end{quote}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle{EXAMPLES --- TYPES \& VALUES (cont.)}
%\begin{quote}\small\begin{verbatim}
%PerMessageSubmissionFields ::=
%    SET {
%...
%        content-type
%            ContentType,
%
%        content-identifier
%            ContentIdentifier OPTIONAL,
%
%        priority
%            Priority DEFAULT normal,
%
%        per-message-indicators
%            PerMessageIndicators DEFAULT {},
%...
%    }
%\end{verbatim}\end{quote}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle{EXAMPLES --- TYPES \& VALUES (cont.)}
%\begin{quote}\small\begin{verbatim}
%PDU ::= 
%    CHOICE {
%        FTAM-Regime-PDU,
%        File-PDU,
%        Bulk-Data-PDU
%    }
%
%SecurityPolicyIdentifier ::=
%        OBJECT IDENTIFIER
%
%\end{verbatim}\end{quote}
%\end{bwslide}


\f

\begin{bwslide}
\ctitle {CONCRETE REPRESENTATION}

\vskip.15in
\begin{verbatim}
struct mail_address {
    char   *local;
    char   *domain;

    unsigned char options;
#define default_local 0x01
#define default_host  0x02
};
\end{verbatim}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {ABSTRACT REPRESENTATION}

\vskip.15in
\begin{verbatim}
Mail-Address ::=
        [APPLICATION 2]
            IMPLICIT SEQUENCE {
                local[0]
                    IMPLICIT GraphicString,

                domain[1]
                    IMPLICIT GraphicString,

                options[2]
                    IMPLICIT BITSTRING {
                        default-local(0), default-host(1)
                    }
                    DEFAULT { default-local, default-host }
            }
\end{verbatim}
\end{bwslide}


\f

\begin{bwslide}
\ctitle{MACROS}

\begin{nrtc}
\item	ALLOW ASN.1 LANGUAGE TO BE DYNAMICALLY EXTENDED
\item	INTENDED TO CAPTURE {\em SOME} ADDITIONAL SEMANTICS
\item	ACTUALLY EXTEND THE ASN.1 GRAMMAR
\item	VERY POWERFUL
\item	\underline{VERY PROBLEMATIC}
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {MACROS --- EXAMPLE}
\begin{quote}\small\begin{verbatim}
<<macro> MACRO ::=

BEGIN

TYPE NOTATION  ::= <<type syntax>>

VALUE NOTATION ::= <<value syntax>>

<<supporting syntax>>

END
\end{verbatim}\end{quote}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {MACROS --- PROBLEMS}

\begin{nrtc}
\item	ACTUALLY CHANGE GRAMMAR RULES OF ASN.1
	\begin{nrtc}
	\item	``NORMAL'' LANGUAGE MACROS ARE JUST TEXT SUBSTITUTIONS
	\end{nrtc}
\item	REQUIRE ASN.1 PARSER TO ACCOMMODATE DYNAMIC GRAMMAR CHANGES
\item	INTEGRAL PART OF ASN.1
\item	DIFFICULT TO ``MANUALLY'' EXPAND
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {MACROS --- PROBLEMS (cont.)}

\begin{nrtc}
\item	MACROS THEMSELVES ARE NOT ENOUGH
	\begin{nrtc}
	\item	ENTIRE SEMANTICS NOT CONVEYED IN NOTATION
	\item	REQUIRES FRONT END TO AUGMENT INPUT BACK END
	\end{nrtc}
\item	REQUIRES SELF--MODIFYING FRONT END COMPILER
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle{EXAMPLES --- MACROS}
\begin{quote}\small\begin{verbatim}
OPERATION MACRO ::=
    BEGIN
    TYPE NOTATION  ::= "ARGUMENT" NamedType Result Errors | empty
    VALUE NOTATION ::= value (VALUE INTEGER)
    Result         ::= "RESULT" NamedType | empty
    Errors         ::= "ERRORS" { ErrorNames } | empty
    
    NamedType      ::= identifier type | type
    ErrorNames     ::= IdentifierList | empty
    IdentifierList ::= identifier | IdentifierList "," identifier
    END

users OPERATION
    RESULT	IA5List
    ERRORS	{ congested, unableToOpenFile }
    ::= 2
\end{verbatim}\end{quote}
\end{bwslide}


%\f

\begin{bwslide}
%\ctitle{EXAMPLES --- MACROS (cont.)}
%\begin{quote}\small\begin{verbatim}
%ERROR MACRO ::=
%    BEGIN
%    TYPE NOTATION  ::= "PARAMETER" NamedType | empty
%    VALUE NOTATION ::= value (VALUE INTEGER)
%    
%    NamedType      ::= identifier type | type
%    END
%
%unableToOpenFile
%    ERROR
%    PARAMETER	IA5List
%    ::= 2
%\end{verbatim}\end{quote}
%\end{bwslide}


\f

\begin{bwslide}
\ctitle{TRANSFER SYNTAX \\ BASIC ENCODING RULES (BER)}

\begin{nrtc}
\item	INDEPENDENT OF MACHINE-DEPENDENT STRUCTURES \& RESTRICTIONS
\item	TAGGED DATA, {\em TAG--LENGTH--VALUE (TLV) APPROACH}
\item	VARIABLE LENGTH ENCODINGS IN MINIMAL OCTETS
\item	SOLID TECHNOLOGY
	\begin{nrtc}
	\item	NOT A CONCERN FOR MOST IMPLEMENTORS
	\end{nrtc}
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {TLV ENCODINGS}

\begin{nrtc}
\item	USE OF TLV IS CONTROVERSIAL
\item	LESS EXTENSIBLE SCHEMES ARE MORE PERFORMANT
\item	EACH FIELD IS VARIABLE LENGTH
\item	FIELDS MAY BE OF ARBITRARY COMPLEXITY
\end{nrtc}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {TLV}

\vskip.5in
\diagram[p]{figureA-27}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {COMPLEX ENCODINGS}

\begin{nrtc}
\item	COMPLEX ASN.1 TYPES COMPOSED OF SEVERAL LESS COMPLEX TYPES
\item	EVENTUALLY BREAK DOWN TO SIMPLE ASN.1 TYPES
\item	BER APPLIED TO SIMPLE TYPES RECURSIVELY TO AN ARBITRARY 
		LEVEL OF COMPLEXITY
\end{nrtc}
\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {ENCODING DETAILS}
%
%\begin{nrtc}
%\item	BIT ORDERING
%	\begin{nrtc}
%	\item	``BIT 8'' IS HIGH ORDER
%	\item	``BIT 1'' IS LOW ORDER
%	\end{nrtc}
%\item	INTEGERS
%	\begin{nrtc}
%	\item	OF ANY VALUE, {\em TWOS--COMPLEMENT}
%	\item	POSITIVE ONLY, {\em UNSIGNED}
%	\end{nrtc}
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {TAG FIELD}
%
%\begin{nrtc}
%\item	PAIR
%	\begin{nrtc}
%	\item	CLASS OF ASN.1 TYPE
%		\begin{nrtc}
%		\item	UNIVERSAL
%		\item	APPLICATION
%		\item	CONTEXT-SPECIFIC
%		\item	PRIVATE
%		\end{nrtc}
%	\item	IDENTIFIER OF ASN.1 TYPE
%		\begin{nrtc}
%		\item	ARBITRARY LENGTH
%		\end{nrtc}
%	\end{nrtc}
%\item	INDICATION IF VALUE IS PRIMITIVE OR CONSTRUCTED
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {TAG FIELD}
%
%\vskip.5in
%\diagram[p]{figureA-29}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle{PRIMATIVE TYPES}
%
%\begin{tabular}{ll}
%INTEGER		& [UNIVERSAL 2] \\
%BOOLEAN		& [UNIVERSAL 1] \\
%NULL		& [UNIVERSAL 5] \\
%OCTET STRING	& [UNIVERSAL 4] \\
%BIT STRING	& [UNIVERSAL 3] \\
%%\\
%%OBJECT IDENTIFIER \\
%%EXTERNAL \\
%%ANY \\
%\end{tabular}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle{CONSTRUCTOR TYPES}
%
%\begin{tabular}{lll}
%SET & [UNIVERSAL 17] & Fixed size set of items of distinct types \\
%SET OF & [UNIVERSAL 17] & Variable size set of items of the same type \\
%SEQUENCE & [UNIVERSAL 16] & Record \\
%SEQUENCE OF & [UNIVERSAL 16] & Array or list \\
%%CHOICE & & One out of a set of possible types \\
%%TAGGED & & For creating a type with a new tag \\
%\end{tabular}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {LENGTH FIELD}
%
%\begin{nrtc}
%\item	INDICATES LENGTH OF VALUE FIELD
%	\begin{nrtc}
%	\item	ACTUAL LENGTH (${2}^{1008}-1$ MAXIMUM)
%	\item	INDEFINITE LENGTH
%		\begin{nrtc}
%		\item	END OF STREAM HAS A SPECIAL MARKER
%		\end{nrtc}
%	\end{nrtc}
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {VALUE FIELD}
%
%\begin{nrtc}
%\item	SIMPLE TYPES
%	\begin{nrtc}
%	\item	{\em SIMPLE} VALUE
%	\end{nrtc}
%\item	CONSTRUCTOR TYPES
%	\begin{nrtc}
%	\item	MULTIPLE SIMPLE ENCODINGS AS VALUE
%	\item	DETERMINING LENGTH IN ADVANCE IS TOUGH PART
%	\item	INDEFINITE LENGTH USED FOR THIS
%		\begin{nrtc}
%		\item	MAKES SENDING EASY
%		\item	RECEIVING MORE DIFFICULT
%		\end{nrtc}
%	\end{nrtc}
%\end{nrtc}
%\end{bwslide}


\f

\begin{bwslide}
\ctitle {VALUE FIELD\\SIMPLE EXAMPLE --- INTEGER 26}

\vskip.5in
\diagram[p]{figureA-28}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {VALUE FIELD\\CONSTRUCTOR EXAMPLE}

\begin{quote}\small\begin{verbatim}
Constructor ::=
    SEQUENCE {
        name
            Name,

        value
            Value
    }
\end{verbatim}\end{quote}
\end{bwslide}


\f

\begin{bwslide}
\ctitle {CONSTRUCTOR EXAMPLE (cont.)}

\vskip.5in
\diagram[p]{figureA-30}
\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {VALUE ``ANY'' FIELDS}
%
%\begin{nrtc}
%\item	OPAQUE FIELD
%\item	SENDING APPLICATION
%	\begin{nrtc}
%	\item	MUST ``KNOW'' WHAT TO SUPPLY
%	\item	SUPPLIED DATA MUST ALREADY HAVE BER APPLIED
%	\end{nrtc}
%\item	RECEIVING APPLICATION
%	\begin{nrtc}
%	\item	CAN EASILY DECODE BER
%	\item	MUST ``KNOW'' WHAT IT IS TO MAKE USE OF DATA
%	\end{nrtc}
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle	{ENCRYPTED}
%
%\begin{nrtc}
%\item	MENTIONED FOR CURIOSITY SAKE
%\item	REQUIRES BILATERAL AGREEMENT ON USE
%\item	DOESN'T PREVENT APPLICATION FROM PERFORMING ENCRYPTION ITSELF
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {IMPORTANT POINT}
%
%\begin{nrtc}
%\item	BER TRANSFER SYNTAX CAN BE PARSED WITHOUT REFERENCE TO THE ABSTRACT
%	SYNTAX, ASN.1
%\end{nrtc}
%\end{bwslide}

	
%\f

\begin{bwslide}
%\ctitle {MAKING ASN.1 WORK}
%
%\begin{nrtc}
%\item	NEED TOOLS TO FACILITATE DEVELOPMENT OF APPLICATIONS
%\item	GENERATION OF ENCODERS, DECODERS \& PRINTERS FOR ABSTRACT SYNTAX
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {TOOLS}
%
%\begin{nrtc}
%\item	FOR ENCODING \& DECODING
%	\begin{nrtc}
%	\item	SEMANTICS OF DATA SUPPLIED BY ASN.1 DESCRIPTION
%	\item	LOCAL STORAGE STRATEGY
%		\begin{nrtc}
%		\item	FIXED
%		\item	DECLARATIONS
%		\item	ACTION ROUTINES
%		\end{nrtc}
%	\end{nrtc}
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {AN APPROACH\\STRUCTURE GENERATOR}
%
%\begin{nrtc}
%\item	FROM ASN.1 DEFINITION, PRODUCE DATA STRUCTURES FOR
%	{\em CONCRETE} STORAGE OF VALUES
%\item	STRUCTURES WILL BE USED BY ENCODERS \& DECODERS
%\item	APPLICATION WILL MANIPULATE STRUCTURES AS WELL
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {AN APPROACH:\\ENCODER/DECODER GENERATOR}
%
%\begin{nrtc}
%\item	GENERATE MODULES TO ENCODE \& DECODE ABSTRACT SYNTAX TO \& FROM
%	CONCRETE DATA STRUCTURES GENERATED IN PREVIOUS STEP
%\item	ALSO GENERATE ``PRETTY PRINTERS'' FOR DISPLAYING PROTOCOL
%\end{nrtc}
%\end{bwslide}


%\f

\begin{bwslide}
%\ctitle {REFERENCES}
%
%\begin{description}
%\item[ISO/IEC 8324:]	Specification of Abstract Syntax Notation One (ASN.1)
%\item[ISO/IEC 8323:]	Specification of Basic Encoding Rules for Abstract 
%			Syntax Notation One (ASN.1)
%\end{description}
%\end{bwslide}