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└─⟦3d0c2be1b⟧ Bits:30001254 ISODE-5.0 Tape └─⟦eba4602b1⟧ »./isode-5.0.tar.Z« └─⟦d3ac74d73⟧ └─⟦this⟧ »isode-5.0/doc/monterey/monterey.tex« └─⟦2d1937cfd⟧ Bits:30007241 EUUGD22: P.P 5.0 └─⟦35176feda⟧ »EurOpenD22/isode/isode-6.tar.Z« └─⟦de7628f85⟧ └─⟦this⟧ »isode-6.0/doc/monterey/monterey.tex«
% run this through SLiTeX \documentstyle [blackandwhite,landscape,oval,pagenumbers,small,plain]{NRslides} \input trademark \def\tradeORGfont{\rm} \def\tradeNAMfont{\rm} \raggedright \begin{document} \title {PROTOCOL ADVANCES 3:\\ ISO DEVELOPMENT ENVIRONMENT} \author {Stephen E.~Kille\\ University College, London\\[0.15in] Ronald G.~Minnich\\ University of Delaware\\[0.15in] Marshall T.~Rose\\ Northrop Corporation} \date {March 17, 1987} \maketitlepage \f \begin{bwslide} \part* {AGENDA}\bf \begin{nrtc} \item ISODE: INTRODUCTION AND STATUS REPORT (ROSE) \item PUTTING ISODE TO WORK (KILLE) \item ISODE AT THE UNIVERSITY OF DELAWARE (MINNICH) \item A STRATEGY FOR CONVERGENCE WITH ISO\\ (ANOTHER SERMON FROM MT.~ROSE?) \end{nrtc} \end{bwslide} \f \begin{bwslide} \part {ISODE:\\ INTRODUCTION AND\\ STATUS REPORT} \end{bwslide} \f \begin{bwslide} \ctitle {ISODE} \begin{nrtc} \item AN OPENLY AVAILABLE ISO DEVELOPMENT ENVIRONMENT \item ISO APPLICATION, PRESENTATION, SESSION, AND LAYERED TRANSPORT \item CODED ENTIRELY IN C \item OPERATING SYSTEMS \begin{nrtc} \item 4.2\bsd/ \unix/ \item SVR2 AT\&T \unix/ WITH AN EXCELAN \exos/~8044 TCP/IP PACKAGE \item \vms/ AND \pcdos/ (STILL) UNDER DEVELOPMENT \end{nrtc} \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {MOTIVATION} \begin{nrtc} \item WANT TO BE CONSISTENT WITH ISO'S DIRECTION, BUT WANT TO GET WORK DONE NOW \begin{nrtc} \item MANY NEW, MAJOR INVESTMENTS BEING MADE IN CURRENT TECHNOLOGY (e.g., NSFnet, NASA's NEW INTERNET, etc.) \end{nrtc} \item CURRENTLY, TCP/IP HAS SEVERAL ADVANTAGES OVER TP4/IP: \begin{nrtc} \item WORKING IS-IS (GATEWAY-GATEWAY) PROTOCOL \item MATURITY \item VENDOR SUPPORT \item LARGE BODY OF EXPERTISE \end{nrtc} \item WOULD LIKE TO WORK IN AN ISO ENVIRONMENT, BUT WILL USE TCP/IP's STRENGTHS TO DO SO NOW \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {THE APPLICATION ENVIRONMENT} \vskip.15in \diagram[p]{figure1} \end{bwslide} \f \begin{note}\em other ASEs: RTSE, CCR, and so on presentation: manage presentation contexts~---~abstract syntax and transfer session: manage tokens, activities, checkpointing, and so on about 35K lines of code \end{note} \f \begin{bwslide} \ctitle {AN ALTERNATE ENVIRONMENT:\\ MHS ARCHITECTURE (c.~1984)} \vskip.15in \diagram[p]{figure2} \end{bwslide} \f \begin{bwslide} \ctitle {APPLICATIONS IN PROGRESS} \begin{nrtc} \item FTAM - FILE TRANSFER, ACCESS AND MANAGEMENT (NRTC) \item MHS - MESSAGE HANDLING SYSTEM (UCL) \item DS - DIRECTORY SERVICES (UCL) \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {PERFORMANCE OBSERVATIONS} \begin{nrtc} \item THE 5-P PRINCIPLE:\\ PROPER PLANNING PREVENTS POOR PERFORMANCE \item INITIAL BENCHMARKING SUGGESTS THROUGHPUT RATES VERY CLOSE TO RAW TCP FOR BOTH TRANSPORT AND SESSION ECHO AND SINK ENTITIES \item AT THE APPLICATION INTERFACE (ABOVE ACSE/ROSE), THROUGHPUT IS ONLY 10\%-12\% WORSE THAN RAW TCP FOR DATA TRANSFER \item RESULTS PRIMARILY DUE TO MINIMIZED BYTE-COPYING BETWEEN LAYERS \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {WHERE NEXT?} \begin{nrtc} \item VALIDATE/TEST AGAINST PURE ISO\\ (SOMEBODY ELSE'S IMPLEMENTATION) \item SYNCHRONIZE WITH GOSIP SPECIFICATION \item EXPAND SOME MODULES AS NEW APPLICATIONS REQUIRE \item CONVERGENCE WORK (DESCRIBED LATER) \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {AVAILABILITY INFORMATION} \begin{nrtc} \item VERSION 2 AVAILABLE MARCH 15, 1987 \item USPS: SEND TAPE AND PREPAID MAILER TO: \begin{small} \[\begin{tabular}{l} NORTHROP RESEARCH AND TECHNOLOGY CENTER\\ ATTN: AUTOMATION SCIENCES LABORATORY (0330/T30)\\ ONE RESEARCH PARK\\ PALOS VERDES PENINSULA, CA 90274\\ USA\\ \end{tabular}\] \end{small} \begin{nrtc} \item ADD 3 POUNDS AND 1--1/2 INCHES FOR DOCUMENTATION SET \item SEND ONLY POSTAGE, NO MONEY \item TELCO: 213--544--5393 \end{nrtc} \item ANONYMOUS FTP: HOST louie.udel.edu, FILE portal/isode-2.tar \end{nrtc} \end{bwslide} \f \begin{bwslide} \part {PUTTING ISODE TO WORK}\large\bf \vskip-0.5in \[\begin{tabular}[t]{c}\large\bf Stephen E.~Kille\\ Department of Computer Science\\ University College, London \end{tabular}\] \end{bwslide} \f \begin{note}\em with credits to: \begin{nrtc} \item at UCL:\\ George G.~Michaelson, Stephen E.~Easterbrook, Thomas Woo \item at the Department of Computer Science, Nottingham University:\\ Julian P.~Onions \end{nrtc} \end{note} \f \begin{bwslide} \ctitle {OVERVIEW} \begin{nrtc} \item DISCUSSION OF WORK AT UCL USING ISODE \item WORK ON DISTRIBUTED APPLICATIONS \item EMPHASIS ON MESSAGE HANDLING AND DIRECTORY SERVICES \item FOCUS ON WORK ALIGNED WITH INTERNATIONAL STANDARDS \item AIM TO DESCRIBE HOW ISODE FACILITATES THIS WORK \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {OSI INFRASTRUCTURE} \begin{nrtc} \item UCL RUNS A WIDE VARIETY OF UNIX SYSTEMS \item NEEDS OSI ENVIRONMENT WHICH CAN OPERATE ON ALL OF THESE, FOR WORKING IN BOTH LANs AND WANs \item CURRENTLY USE TCP/IP OVER THE LAN, AS THIS IS THE ONLY PROTOCOL COMMON TO ALL OF THE MACHINES IN QUESTION \item TP0/X.25 WILL BE USED FOR WAN ACCESS \item TP4 MAY ALSO BE USED (IF WE HAVE TO) \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {ADVANTAGES OF TP0/X.25} \begin{nrtc} \item THE PREFERRED EUROPEAN APPROACH \item EFFICIENT UTILIZATION OF PTT X.25 SERVICES \item UTILIZATION OF X.25 HARDWARE TO REDUCE CPU LOAD \item WILL ALLOW FOR EXTENSIVE TESTING OF ISODE AGAINST OTHER OSI IMPLEMENTATIONS AT UCL AND ELSEWHERE \item MIGRATION TO USE OF X.25 OVER IEEE~802 LLC \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {ABSTRACT SYNTAX NOTATION 1 (ASN.1)} \begin{nrtc} \item REPRESENTATION CURRENTLY USED BY ALL OSI APPLICATIONS \item RICH, EXTENSIBLE SYNTAX \item USEFUL FOR SPECIFICATION OF NEW PROTOCOLS \begin{nrtc} \item CLEAR TO READ SPECIFICATIONS \item NOT TIED TO MACHINE-ORIENTED STRUCTURES AND RESTRICTIONS \end{nrtc} \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {REMOTE OPERATIONS SERVICE (ROS)} \begin{nrtc} \item STANDARDIZED MECHANISM FOR SPECIFYING TRANSACTIONS \item MAKES FULL POWER OF ASN.1 AVAILABLE \item USED IN MANY INTERESTING OSI APPLICATIONS \begin{nrtc} \item MESSAGING \item DIRECTORY SERVICES \item NETWORK MANAGEMENT \item REMOTE DATABASE ACCESS \end{nrtc} \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle{WHY ISODE} \begin{nrtc} \item FULL AND UP-TO-DATE IMPLEMENTATION OF OSI LAYERS \item REMOTE OPERATIONS SERVICE \item ASN.1 ELEMENT HANDLING \item COMPILER FOR DECODING ASN.1 (PEPY) \item FLEXIBILITY TO USE DIFFERENT TRANSPORT SERVICES \item GOOD PERFORMANCE \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle{RARE DIRECTORY SERVICES} \begin{nrtc} \item R\'{E}SEAUX ASSOCI\'{E}S POUR LA RECHERCHE EUROP\'{E}ENNE (RARE) \item TRANSLATION: EUROPEAN ACADEMIC RESEARCH NETWORK \item AN ASSOCIATION OF THE VARIOUS NATIONAL RESEARCH NETS \item WISH TO PROVIDE EARLY DIRECTORY SERVICES, UTILIZING A CENTRAL DATABASE (LIKE THE ARPA ``WHOIS'') \item CONTAINS FACILITY, PROJECT, AND PERSON DATA \item THE DATA IS MORE VALUABLE THAN THE INITIAL SERVICE \item DATA STANDARD FORMAT IS DESIRED \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle{RARE ASN.1 STRUCTURE} \begin{nrtc} \item UCL HAS SPECIFIED A FIRST VERSIONS OF THE DATA STRUCTURE \item ASN.1 USED \item CAN REPRESENT DETAILED STRUCTURE, WHICH WILL BE USEFUL IN LATER DISTRIBUTED DIRECTORY SERVICES \item PEPY (ISODE) MADE ASN.1 VERIFICATION STRAIGHTFORWARD IN THE DESIGN PHASE \item ALLOWED EASY IMPLEMENTATION OF ``PRETTY PRINTER'' AND ENCODING OF TEST DATA \item IS LIKELY TO BE USED TO SUPPORT THE WIDER INTRODUCTION OF THIS FORMAT FOR ENCODING AND DECODING \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle{NRS LOOKUP PROTOCOL} \begin{nrtc} \item NAME REGISTRATION SCHEME (NRS) IS A DATABASE OF THE HOSTS (DOMAINS) IN THE UK ACADEMIC COMMUNITY. \item CURRENTLY CONTAINS ABOUT 1000 HOSTS, AND IS GROWING RAPIDLY \item THE CENTRALIZED DATABASE HAS DISTRIBUTED MANAGEMENT AND IS WIDELY REPLICATED \item NRS LOOKUP PROTOCOL SPECIFIES A LIGHTWEIGHT TRANSACTION OVER X.25, TO ENABLE LOOKUP OF INFORMATION IN THE NRS \item THE PACKET FORMATS ARE SPECIFIED IN ASN.1 \item HANDLES BOTH CURRENT ``COLOURED BOOK'' APPLICATIONS AND PLANNED OSI APPLICATIONS \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle{NRS LOOKUP PROTOCOL IMPLEMENTATION} \begin{nrtc} \item IMPLEMENTATION DONE IN PARALLEL WITH FINAL WORK ON SPECIFICATION \item 3RD YEAR STUDENT PROJECT (3 MONTHS) \item PEPY FOUND A NUMBER OF ERRORS IN THE PROTOCOL SPECIFICATION \item PEPY ALLOWED A FULL PROTOCOL DECODER TO BE BUILT WITH MINIMUM EFFORT \item EARLY RESULTS SUGGEST GOOD PERFORMANCE \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle{MESSAGE HANDLING} \begin{nrtc} \item UCL AND NOTTINGHAM UNIVERSITY ARE DEVELOPING AN X.400 SYSTEM (PP) \item OWES MANY OF ITS DESIGN IDEAS TO MMDF (THE CSNET MESSAGE SYSTEM) \item FLEXIBLE HANDLING OF MULTI-MEDIA \item PROTOCOL AND FORMAT CONVERSION \item UTILIZATION WITH DIRECTORY SERVICES \item MAY BE DISTRIBUTED WITH LATER VERSIONS OF ISODE \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle{CURRENT USE OF ISODE IN PP} \begin{nrtc} \item MOST OF THE EARLY WORK HAS NOT NEEDED ISODE \item PEPY CAN HANDLE P1 AND P2 \item INTEGRATION OF P1 AND ISODE'S RELIABLE TRANSFER SERVICE (RTS) HAS STARTED AND HAS BEEN SATISFYINGLY STRAIGHTFORWARD \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle{PLANNED USE OF ISODE IN PP} \begin{nrtc} \item RFC987 WILL BE IMPLEMENTED, TO PROVIDE FULL MAPPINGS BETWEEN X.400 AND RFC822 MAIL \item QUEUE MANAGEMENT WILL UTILIZE A ROS PROTOCOL \begin{nrtc} \item THIS WILL PROVIDE HIGH FUNCTIONALITY, AND ALLOW FOR REMOTE MANAGEMENT \end{nrtc} \item A SYSTEM FOR MANAGING LOCAL LISTS WILL BE SPECIFIED IN ROS \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle{UCL DIRECTORIES} \begin{nrtc} \item HAVE ESTABLISHED DATABASE OF UCL USERS IN CENTRAL DATABASE \begin{nrtc} \item DATA SEEMS TO BE A PRE-REQUISITE OF A DIRECTORY SERVICE! \end{nrtc} \item ACCESS USING ROS TO ALLOW INFORMATION TO BE UPDATED AND QUERIED \item GENERATION OF LOCAL MAIL TABLES IS AUTOMATED FROM THIS DATABASE \item ALL UCL PASSWORD FILES ARE MANAGED FROM THIS DATABASE \begin{nrtc}\small \item MUCH HARDER THAN WE THOUGHT \item ALL PASSWORD FILE RELATED TOOLS (passwd(1), chsh(1), etc.) EMULATED OVER ROS \item SOME EXTENSIONS (E.G., ABILITY TO CHANGE PASSWORDS ON ALL MACHINES) \item PASSWORD FILES PULLED BY MACHINES USING ROS \item UCL SPECIFIC (SIMPLE) APPROACH TO AUTHENTICATION \end{nrtc} \item CURRENT SYSTEM IS SEEN AS A STEPPING STONE TO FULL OSI DIRECTORY SERVICES \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle{WORK AT UCL TO EXTEND ISODE} \begin{nrtc} \item TOOLS TO FACILITATE DEVELOPMENT OF APPLICATIONS ARE SEEN AS CRITICAL \item CURRENTLY EXTENDING PEPY TO PERFORM ENCODING AS WELL AS DECODING \item WILL EXTEND PEPY TO SUPPORT ROS IN AN AUTOMATIC MANNER, MIXING ENCODING AND DECODING FUNCTIONS \item ENABLE ROS TO BE USED IN A MANNER VERY LIKE SOME REMOTE PROCEDURE CALL APPROACHES \end{nrtc} \end{bwslide} \f \begin{bwslide} \part {ISODE AT\\ THE UNIVERSITY OF DELAWARE}\bf \vskip-0.5in \[\begin{tabular}[t]{c}\large\bf Ronald G.~Minnich\\ Dept. of Electrical Engineering\\ University of Delaware \end{tabular}\hskip1em plus.17fil \begin{tabular}[t]{c}\large\bf David J.~Farber\\ Dept. of Electrical Engineering\\ Dept. of Computer and Information Sciences\\ University of Delaware \end{tabular}\] \end{bwslide} \f \begin{bwslide} \ctitle {STANDARD DISCLAIMER} \begin{nrtc} \item ISODE HAS JUST COME INTO USE AT UDEL AS OF 1987 \item WE KNOW ABOUT ISO BUT HAVE NEVER USED ISO OR ISODE~--- \begin{nrtc} \item WE ARE NOT ALONE IN THAT; THAT IS WHY ISODE EXISTS \end{nrtc} \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {ISODE AFFECTS THREE AREAS} \begin{nrtc} \item EXPERIMENTAL COMPUTER NETWORK RESEARCH \item SYSTEMS PROGRAMMING \item APPLICATIONS PROGRAMMING \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {IMPLICATIONS OF ISO FOR OUR NETWORK RESEARCH} \begin{nrtc} \item IF THE ISO MODEL IS THE FUTURE, THEN xxxNET HAD BETTER SUPPORT IT EFFECTIVELY \item WE HAVE SEEN A SIMILAR PHENOMENON WITH UNIX AND COMPUTER ARCHITECTURE \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {EXPERIMENTAL COMPUTER NETWORK RESEARCH} \begin{nrtc} \item MEMNET[DELP86]~---~LARGE PHYSICALLY DISTRIBUTED MEMORY CONNECTED BY A TOKEN RING \begin{nrtc} \item IT IS UNDER CONSTRUCTION NOW AND SIMULATIONS PREDICT VERY HIGH THROUGHPUT \item WE ARE CONSIDERING PUTTING ISODE ON TOP OF MEMNET; MEMNET BECOMES THE TRANSPORT \item WE CONSIDER THIS A GOOD TEST OF MEMNET'S CAPABILITIES AS WELL AS BEING POTENTIALLY WORTHWHILE IN AND OF ITSELF \end{nrtc} \item NOAHNET[PARULKAR86]~---~FLOOD NETWORK \begin{nrtc} \item WHAT IMPLICATIONS DOES THE ISO MODEL HAVE FOR NOAHNET? \end{nrtc} \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {ISO FOR SYSTEMS PROGRAMMING} \begin{nrtc} \item WE NEED TO LEARN HOW TO USE IT FOR `HOUSEKEEPING'\\ (e.g. KERNAL DATA STRUCTURE MONITORS, FONT LOADERS,\\ MAN PAGE PROGRAMS, etc.) \item WHERE WE HAVE BEEN USING THE UNSTRUCTURED ``PIPE''-LIKE CHANNEL PROVIDED BY TCP/IP, WE NOW USE THE HIGHER-LEVEL ISO CONSTRUCTS \item A LOGICAL CONSEQUENCE OF THE ABOVE IS THAT WE WILL NOT NEED AS MANY CUSTOM PROTOCOLS (e.g., rdump, rman, etc.) AND WILL THUS (WE HOPE) HAVE LESS CONFUSION WHEN AN 'r'-PROGRAM BREAKS (AND THEY HAVE~---~EXAMPLE ON REQUEST) \item ISODE AND PEPY MAKE THE PROCESS MUCH EASIER \end{nrtc} \end{bwslide} \f \begin{note}\em example slides here... \end{note} \f \begin{bwslide} \ctitle {WHERE DO I SIGN?} \begin{nrtc} \item BUT: WE HAVE TO CLIMB A STEEP LEARNING CURVE \item MUCH BIGGER BUT: WE HAVE TO CONVINCE OTHERS TO CLIMB IT TOO \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {ISO FOR THE APPLICATIONS PROGRAMMER} \begin{nrtc} \item MAIL SYSTEMS \item MULTI-MEDIA SYSTEMS (E.G. NETWORKED APA DISPLAYS) \item NETWORK MONITORING PROGRAMS[AMER87] \item IMAGE PROCESSING \item SPEECH PROCESSING \item NETWORKED PCs~---~USING PCs TO HELP MANAGE VAX RESOURCES \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {TWO PROBLEMS} \begin{nrtc} \item CONVINCING VERY BUSY PEOPLE TO TAKE THE TIME TO LEARN IT \item ONCE THEY LEARN IT, DO THEY FIND IT BOTH USABLE AND USEFUL? \end{nrtc} SO FAR, AT UDEL, THERE IS NOT ENOUGH TIME TO TELL \end{bwslide} \f \begin{bwslide} \ctitle {CONCLUSIONS} \begin{nrtc} \item EXPERIMENTAL NETWORKS AT UDEL WILL SUPPORT ISODE \begin{nrtc} \item BOTH AS A TEST OF ISODE\\ AND AS A TEST OF THE NETWORK \end{nrtc} \item WE ARE PLANNING TO USE ISODE FOR SYSTEM PROGRAMS THAT PREVIOUSLY WOULD HAVE BEEN IMPLEMENTED IN THE 'r'-PROGRAM STYLE OR THAT COULD NOT HAVE BEEN EASILY WRITTEN AT ALL \item WE ARE ENCOURAGING OTHER RESEARCHERS AT UDEL TO USE ISODE FOR THEIR APPLICATIONS \end{nrtc} \end{bwslide} \f \begin{bwslide} \part {A STRATEGY FOR CONVERGENCE WITH ISO}\bf \vskip-0.5in \[\begin{tabular}[t]{c}\large\bf Marshall T.~Rose\\ Computer Science Laboratory\\ Northrop Research and Technology Center \end{tabular}\] \end{bwslide} \f \begin{bwslide} \ctitle {THE PROBLEM} \begin{nrtc} \item TCP/IP IS HERE NOW AND IT WORKS \item ISO IS INEVITABLE! \item HOW DO WE GET TO THERE FROM HERE? \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {PREMISES} \begin{nrtc} \item START WITH AN EXISTING TCP/IP INTERNET \item ADD SOME ISO-ONLY HOSTS/NETWORKS \item MAKE NO MODIFICATIONS TO ISO-ONLY HOSTS (AND MINIMIZE CHANGES TO TCP/IP HOSTS) \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {DESIRED INTEROPERABILITY} \begin{nrtc} \item WANT SERVICES BETWEEN END-SYSTEMS AT HIGHER-LEVELS \item AVOID APPLICATION-LEVEL GATEWAYS \item IMPLIES INTEROPERABILITY AT TRANSPORT LAYER AND ABOVE \item CONVERGE ON HIGHER-LEVELS IN THE ISO SUITE \item NEEDED: VIRTUAL TRANSPORT SERVICE \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {TCP TRANSPORT SERVICE} \vspace{0.25in} \diagram[p]{figure3a} \end{bwslide} \f \begin{bwslide} \ctitle {ISO TRANSPORT SERVICE} \vspace{0.25in} \diagram[p]{figure3b} \end{bwslide} \f \begin{bwslide} \ctitle {A CONVERGENCE STRATEGY} \begin{nrtc} \item NEED TWO THINGS: \begin{nrtc} \item HIGHER-LEVEL ISO SERVICES FOR TCP/IP HOSTS \item ISO-IP ENCAPSULATION ON DDN-IP \end{nrtc} \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {VIRTUAL ISO TRANSPORT SERVICE} \vspace{0.25in} \diagram[p]{figure3c} \end{bwslide} \f \begin{bwslide} \ctitle {ISO DEVELOPMENT ENVIRONMENT} \begin{nrtc} \item PROVIDES HIGHER-LEVEL ISO SERVICES FOR TCP/IP HOSTS \item A MAGIC-BOX OFFERS TP4 SERVICE OVER TCP (RFC983) \item GAIN EXPERIENCE WITH THE ISO SUITE \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {ISO TRANSPORT SERVICES ON TOP OF THE TCP} \diagram[p]{figure4} \end{bwslide} \f \begin{bwslide} \ctitle {MIXED ISO TRANSPORT SERVICE} \vspace{0.25in} \diagram[p]{figure3d} \end{bwslide} \f \begin{bwslide} \ctitle {DUAL-IP ``GATEWAYS''} \begin{nrtc} \item NEED TWO MORE THINGS: \begin{nrtc} \item PUT A REAL TP4 AND ISO-IP IN THE HYBRID HOST \item WITH ISO-IP ENCAPSULATED IN DDN-IP \end{nrtc} \end{nrtc} \end{bwslide} \f \begin{bwslide} \ctitle {HYBRID HOST} \diagram[p]{figure5} \end{bwslide} \f \begin{bwslide} \ctitle {THE BIG PICTURE} \vspace{0.25in} \diagram[p]{figure6} \end{bwslide} \f \begin{bwslide} \ctitle {VIRTUAL TRANSPORT SERVICES (REVIEW)} \vspace{0.25in} \diagram[p]{figure7} \end{bwslide} \f \begin{note}\em to migrate: just stop buying tcp/ip when both of these are done you need an application gateway to go from tcp/ip-only to iso-only (essential for mail, probably not needed otherwise) \end{note} \end{document}