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1.1     ! root        1: % run this through LaTeX with the appropriate wrapper
        !             2: 
        !             3: \dotopic{2}
        !             4: \begin{bwslide}
        !             5: \part  {TRANSITION AND\\ COEXISTENCE\\ WITH TCP/IP}
        !             6: \end{bwslide}
        !             7: \doparts
        !             8: 
        !             9: 
        !            10: \begin{bwslide}
        !            11: \part* {OUTLINE}\bf
        !            12: 
        !            13: \begin{description}
        !            14: \item[PART I:]         MOTIVATION
        !            15: 
        !            16: \item[PART II:]                BACKGROUND
        !            17: 
        !            18: \item[PART III:]       PROTOCOL-BASED APPROACHES
        !            19: 
        !            20: \item[PART IV:]                SERVICE-BASED APPROACHES
        !            21: 
        !            22: \item[PART V:]         EXAMPLES
        !            23: \end{description}
        !            24: \end{bwslide}
        !            25: 
        !            26: 
        !            27: \begin{bwslide}
        !            28: \part  {MOTIVATION}\bf
        !            29: 
        !            30: \begin{nrtc}
        !            31: \item  THERE ARE MANY TCP/IP NETWORKS TODAY; THERE WILL BE MORE TOMORROW
        !            32: 
        !            33: \item  BY THE TIME OSI BECOMES A WORTHWHILE OPERATIONAL ALTERNATIVE,
        !            34:        THERE WILL BE MANY MORE TCP/IP NETWORKS THAN THERE ARE TODAY!
        !            35: 
        !            36: \item  PROBLEM: HOW TO PROTECT INSTALLED BASE?
        !            37: 
        !            38: \item  PROBLEM: HOW TO TRANSITION GRACEFULLY?
        !            39: \end{nrtc}
        !            40: \end{bwslide}
        !            41: 
        !            42: 
        !            43: \begin{bwslide}
        !            44: \ctitle        {GROWTH OF TCP/IP}
        !            45: 
        !            46: \begin{nrtc}
        !            47: \item  SALES OF TCP/IP-BASED TECHNOLOGY
        !            48:     \begin{nrtc}
        !            49:     \item      PARTICULARLY IN EUROPE
        !            50:     \end{nrtc}
        !            51:        CONTINUES TO GROW
        !            52: 
        !            53: \item  SEVERAL TECHNICAL AND MARKET ASPECTS CONTRIBUTE TO THIS PHENOMENA:
        !            54:     \begin{nrtc}
        !            55:     \item      SUPERIORITY OF TCP/IP IN LOWER-LAYER CONNECTIVITY
        !            56: 
        !            57:     \item      MATURITY OF TCP/IP PRODUCTS\\ (e.g., RANGE OF PLATFORMS)
        !            58:     \end{nrtc}
        !            59: 
        !            60: \item  ALTHOUGH OSI WILL DOMINATE, IT DOESN'T YET
        !            61: 
        !            62: \item  HENCE, TCP/IP IS BECOMING MORE FIRMLY ENTRENCHED
        !            63: \end{nrtc}
        !            64: \end{bwslide}
        !            65: 
        !            66: 
        !            67: \begin{bwslide}
        !            68: \ctitle        {FEAR AND LOATHING IN THE MARKET}
        !            69: 
        !            70: \begin{nrtc}
        !            71: \item  F.U.D. IN THE MARKETPLACE:
        !            72: \begin{quote}\em
        !            73: ``All marketing is fear, uncertainty, and doubt.''\\ \raggedleft
        !            74: -- Einar Stefferud, Network Management Associates
        !            75: \end{quote}
        !            76: 
        !            77: \item  WHAT THE VENDORS SAY:
        !            78: \begin{quote}\em
        !            79: ``$\ldots$ protect your investment while assuring a path to an OSI
        !            80: future.''\\ \raggedleft
        !            81: -- Vendor A
        !            82: \end{quote}
        !            83: AND
        !            84: \begin{quote}\em
        !            85: ``$\ldots$ plans for a smooth, painless guaranteed migration to OSI standards
        !            86: as they are approved.''\\ \raggedleft
        !            87: --Vendor B
        !            88: \end{quote}
        !            89: AND
        !            90: \begin{quote}\em
        !            91: ``Once you've scrapped your existing production networks,
        !            92: come to us for OSI.
        !            93: It will be wonderful!''\\ \raggedleft
        !            94: --Vendor C
        !            95: \end{quote}
        !            96: \end{nrtc}
        !            97: \end{bwslide}
        !            98: 
        !            99: 
        !           100: \begin{bwslide}
        !           101: \ctitle        {THE SAD TRUTH}
        !           102: 
        !           103: \begin{quote}\em
        !           104: ``You can't win, and you can't quit, but you \underline{can} reduce the
        !           105: pain.''\\ \raggedleft
        !           106: -- Marshall Rose, NYSERNet, Inc.
        !           107: \end{quote}
        !           108: \end{bwslide}
        !           109: 
        !           110: 
        !           111: \begin{bwslide}
        !           112: \part  {BACKGROUND}\bf
        !           113: 
        !           114: \begin{nrtc}
        !           115: \item  CONCEPTS
        !           116: 
        !           117: \item  TERMINOLOGY
        !           118: 
        !           119: \item  HISTORY
        !           120: 
        !           121: \item  METRICS FOR COMPARISON
        !           122: \end{nrtc}
        !           123: \end{bwslide}
        !           124: 
        !           125: 
        !           126: \begin{bwslide}
        !           127: \ctitle        {THE FUNDAMENTAL ASSUMPTION}
        !           128: 
        !           129: \begin{nrtc}
        !           130: \item  TCP/IP IS HERE TODAY, WIDELY INSTALLED, AND USEFUL
        !           131: 
        !           132: \item  OSI WILL EVENTUALLY REPLACE TCP/IP AS THE OFF-THE-SHELF TECHNOLOGY FOR
        !           133:        BUILDING INTEROPERABLE SYSTMS
        !           134: 
        !           135: \item  BOTH WILL BE SIMULTANEOUSLY WIDESPREAD FOR QUITE SOME TIME
        !           136:     \begin{nrtc}
        !           137:     \item      DURING WHICH OSI WILL GAIN DOMINANCE
        !           138:     \end{nrtc}
        !           139: \end{nrtc}
        !           140: \end{bwslide}
        !           141: 
        !           142: 
        !           143: \begin{bwslide}
        !           144: \part* {CONCEPTS}\bf
        !           145: 
        !           146: \begin{nrtc}
        !           147: \item  TRANSITION:
        !           148:     \begin{nrtc}
        !           149:     \item      TO MOVE FROM ONE PROTOCOL SUITE TO ANOTHER
        !           150:     \end{nrtc}
        !           151: 
        !           152: \item  COEXISTENCE:
        !           153:     \begin{nrtc}
        !           154:     \item      TO LIVE TOGETHER WITHOUT HOSTILITY OR CONFLICT DESPITE
        !           155:                DIFFERENCES
        !           156:     \end{nrtc}
        !           157: 
        !           158: \item  MIGRATION:
        !           159:     \begin{nrtc}
        !           160:     \item      TO MOVE BACK AND FORTH, AS THE SEASONS CHANGE
        !           161:     \end{nrtc}
        !           162: \end{nrtc}
        !           163: \end{bwslide}
        !           164: 
        !           165: 
        !           166: \begin{bwslide}
        !           167: \ctitle        {MAPPINGS}
        !           168: 
        !           169: \begin{nrtc}
        !           170: \item  TRANSITION AND COEXISTENCE CAN BE DESCRIBED BY THE MAPPINGS THEY
        !           171:        REQUIRE
        !           172: 
        !           173: \item  SOME MAPPINGS ARE SIMPLE
        !           174:     \begin{nrtc}
        !           175:     \item      i.e., SYNTACTIC CHANGES
        !           176:     \end{nrtc}
        !           177: 
        !           178: \item  SOME MAPPINGS ARE COMPLEX
        !           179:     \begin{nrtc}
        !           180:     \item      i.e., SEMANTIC CHANGES
        !           181:     \end{nrtc}
        !           182: 
        !           183: \item  THE MORE COMPLEX THE MAPPING, THE GREATER THE LOSS OF INFORMATION OR
        !           184:        INTENT
        !           185: \end{nrtc}
        !           186: \end{bwslide}
        !           187: 
        !           188: 
        !           189: \begin{bwslide}
        !           190: \part* {TERMINOLOGY}\bf
        !           191: 
        !           192: \begin{nrtc}
        !           193: \item  WE'LL FAVOR OSI TERMINOLOGY, BUT STILL NEED SOME INTERNET (TCP/IP)
        !           194:        TERMINOLOGY
        !           195: 
        !           196: \item  TWO BASIC TERMS
        !           197:     \begin{nrtc}
        !           198:     \item      GATEWAY: GENERIC TO ANY LEVEL, COMPLEX
        !           199: 
        !           200:     \item      BRIDGE: GENERIC TO ANY LEVEL, SIMPLE
        !           201:     \end{nrtc}
        !           202: \end{nrtc}
        !           203: \end{bwslide}
        !           204: 
        !           205: 
        !           206: \begin{bwslide}
        !           207: \ctitle        {SERVICE SEMANTICS}
        !           208: 
        !           209: \begin{nrtc}
        !           210: \item  STORE-AND-FORWARD
        !           211:     \begin{nrtc}
        !           212:     \item      SERVICE SEMANTICS CARRIED MULTI-HOP VIA FORWARDERS
        !           213:     \end{nrtc}
        !           214: 
        !           215: \item  END-TO-END
        !           216:     \begin{nrtc}
        !           217:     \item      SERVICE SEMANTICS CARRIED FROM ORIGINATOR TO RECIPIENT
        !           218: 
        !           219:     \item      MAY BE SUPPORTED BY AN UNDERYLING STORE-AND-FORWARD SERVICE
        !           220:     \end{nrtc}
        !           221: \end{nrtc}
        !           222: \end{bwslide}
        !           223: 
        !           224: 
        !           225: \begin{bwslide}
        !           226: \ctitle        {SERVICE SEMANTICS (cont.)}
        !           227: 
        !           228: \vskip.5in
        !           229: \diagram[p]{figureT-3}
        !           230: \end{bwslide}
        !           231: 
        !           232: 
        !           233: \begin{bwslide}
        !           234: \ctitle        {PROTOCOL SUITE}
        !           235: 
        !           236: \begin{nrtc}
        !           237: \item  A COLLECTION OF SERVICES AND PROTOCOLS RELATED:
        !           238:     \begin{nrtc}
        !           239:     \item      ADMINISTRATIVELY, BY AN ORGANIZATION\\ (e.g., ISO/IEC); and,
        !           240: 
        !           241:     \item      PHILOSOPHICALLY, BY A REFERENCE MODEL\\ (e.g., the OSIRM)
        !           242:     \end{nrtc}
        !           243: 
        !           244: \item  FOR OUR PURPOSES, THERE ARE ONLY TWO:
        !           245:     \begin{nrtc}
        !           246:     \item      THE OSI SUITE OF PROTOCOLS
        !           247: 
        !           248:     \item      THE INTERNET SUITE OF PROTOCOLS
        !           249:     \end{nrtc}
        !           250: \end{nrtc}
        !           251: \end{bwslide}
        !           252: 
        !           253: 
        !           254: \begin{bwslide}
        !           255: \ctitle        {APPLICATIONS}
        !           256: 
        !           257: \begin{nrtc}
        !           258: \item  APPLICATION CLASS
        !           259:     \begin{nrtc}
        !           260:     \item      A SET OF APPLICATIONS RELATED TO A PARTICULAR ACTIVITY,
        !           261:                e.g., FILE TRANSFER, IRREGARDLESS OF PROTOCOL SUITE
        !           262:     \end{nrtc}
        !           263: 
        !           264: \item  APPLICATION INSTANCE
        !           265:     \begin{nrtc}
        !           266:     \item      A MEMBER OF AN APPLICATION CLASS SPECIFIC TO A PARTICULAR
        !           267:                PROTOCOL SUITE, e.g., FTAM
        !           268:     \end{nrtc}
        !           269: \end{nrtc}
        !           270: \end{bwslide}
        !           271: 
        !           272: 
        !           273: \begin{bwslide}
        !           274: \part* {HISTORY}\bf
        !           275: 
        !           276: \begin{nrtc}
        !           277: \item  A VERY BRIEF INTRODUCTION TO THE TWO PROTOCOL SUITES
        !           278: 
        !           279: \item  WE'LL ATTEMPT TO TAKE A NON-PARTISAN VIEW (ha!)
        !           280: \end{nrtc}
        !           281: \end{bwslide}
        !           282: 
        !           283: 
        !           284: \begin{bwslide}
        !           285: \ctitle        {INTERNET SUITE}
        !           286: 
        !           287: \begin{nrtc}
        !           288: \item  SPONSORED BY THE U.S.~DoD
        !           289:     \begin{nrtc}
        !           290:     \item      GREW OUT OF EARLY (D)ARPA RESEARCH INTO SURVIVABLE NETWORKS
        !           291:     \end{nrtc}
        !           292:     BASIS FROM THE DoD INTERNET ARCHITECTURE MODEL
        !           293: 
        !           294: \item  SPECIFIED IN ``REQUEST FOR COMMENTS'' SERIES (RFCs) AND
        !           295:        U.S.~MILITARY STANDARDS (MILSTDs)
        !           296: 
        !           297: \item  CURRENT GENERATION PRIMARILY BASED ON
        !           298:     \begin{nrtc}
        !           299:     \item      CONNECTION-ORIENTED TRANSPORT SERVICE,
        !           300:                PROVIDED BY THE TCP; AND,
        !           301: 
        !           302:     \item      CONNECTIONLESS-MODE NETWORK SERVICE,
        !           303:                PROVIDED BY THE IP
        !           304:     \end{nrtc}
        !           305: 
        !           306: \item  MAJOR EMPHASIS ON CONNECTIVITY OF DIVERSE SUB-NETWORKS
        !           307:     \begin{nrtc}
        !           308:     \item      EXCELLENT RESEARCH CONTINUES, TO THIS DAY, ON THESE ISSUES
        !           309:     \end{nrtc}
        !           310: \end{nrtc}
        !           311: \end{bwslide}
        !           312: 
        !           313: 
        !           314: \begin{bwslide}
        !           315: \ctitle        {INTERNET SUITE (cont.)}
        !           316: 
        !           317: \begin{nrtc}
        !           318: \item  SEVERAL PRODUCTION APPLICATIONS
        !           319:     \begin{nrtc}
        !           320:     \item      SIMPLE MAIL TRANSFER PROTOCOL (SMTP)
        !           321: 
        !           322:     \item      FILE TRANSFER PROTOCOL (FTP)
        !           323: 
        !           324:     \item      TELNET (VIRTUAL TERMINAL PROTOCOL)
        !           325: 
        !           326:     \item      DOMAIN NAME SYSTEM (DNS)
        !           327:     \end{nrtc}
        !           328:     ALL OF WHICH ARE RATHER SIMPLE
        !           329: 
        !           330: \item  APPLICATIONS CONTAIN THEIR OWN IMPLICIT SESSION AND PRESENTATION
        !           331:        MECHANISMS
        !           332: 
        !           333: \item  NOT SURPRISING, CONSIDERING THAT THESE APPLICATIONS ARE ALL BASED ON
        !           334:        15~YEAR OLD MODELS!
        !           335: \end{nrtc}
        !           336: \end{bwslide}
        !           337: 
        !           338: 
        !           339: \begin{bwslide}
        !           340: \ctitle        {INTERNET PROTOCOLS}
        !           341: 
        !           342: \vskip.5in
        !           343: \diagram[p]{figureT-4}
        !           344: \end{bwslide}
        !           345: 
        !           346: 
        !           347: \begin{bwslide}
        !           348: \ctitle        {OSI SUITE}
        !           349: 
        !           350: \begin{nrtc}
        !           351: \item  SPONSORED BY THE INTERNATIONAL COMMUNITY
        !           352:     \begin{nrtc}
        !           353:     \item      IN PARTICULAR THE ISO
        !           354:     \end{nrtc}
        !           355:     BASIS FROM THE OSI REFERENCE MODEL (OSIRM)
        !           356: 
        !           357: \item  SPECIFIED IN ``STANDARDS'' (ISO/IEC)  AND RECOMMENDATIONS (CCITT)
        !           358: 
        !           359: \item  BASED ON
        !           360:     \begin{nrtc}
        !           361:     \item      CONNECTION-ORIENTED TRANSPORT SERVICE,
        !           362:                PROVIDED BY ONE OF FIVE DIFFERENT TPs; DEPENDING ON
        !           363: 
        !           364:     \item      THE NETWORK SERVICE AVAILABLE (CONS or CLNS)
        !           365:     \end{nrtc}
        !           366: 
        !           367: \item  DIFFICULT TO IDENTIFY THE ``MAJOR'' EMPHASIS
        !           368: \end{nrtc}
        !           369: \end{bwslide}
        !           370: 
        !           371: 
        !           372: \begin{bwslide}
        !           373: \ctitle        {OSI SUITE (cont.)}
        !           374: 
        !           375: \begin{nrtc}
        !           376: \item  SEVERAL INTERESTING APPLICATIONS
        !           377:     \begin{nrtc}
        !           378:     \item      MESSAGE HANDLING SYSTEMS (MHS)
        !           379: 
        !           380:     \item      FILE TRANSFER, ACCESS AND MANAGEMENT (FTAM)
        !           381: 
        !           382:     \item      VIRTUAL TERMINAL (VT)
        !           383: 
        !           384:     \item      DIRECTORY SERVICES (DS)
        !           385:     \end{nrtc}
        !           386: 
        !           387: \item  APPLICATIONS EVOLVING QUITE HEAVILY OVER THE LAST FEW YEARS
        !           388: 
        !           389: \item  MUCH MORE AMBITIOUS THAN THEIR INTERNET COUNTERPARTS
        !           390: \end{nrtc}
        !           391: \end{bwslide}
        !           392: 
        !           393: 
        !           394: \begin{bwslide}
        !           395: %%%\ctitle     {OSI PROTOCOLS}
        !           396: 
        !           397: %%%\vskip.25in
        !           398: \diagram[p]{figureT-5}
        !           399: \end{bwslide}
        !           400: 
        !           401: 
        !           402: \begin{bwslide}
        !           403: \ctitle        {A BRIEF COMPARISON}
        !           404: 
        !           405: \begin{nrtc}
        !           406: \item  NOTE THAT CONCERNS DIFFER
        !           407:     \begin{nrtc}
        !           408:     \item      NETWORK USERS: APPLICATION-LEVEL FUNCTIONALITY
        !           409: 
        !           410:     \item      NETWORK ADMINISTRATORS: NETWORK AND TRANSPORT ISSUES
        !           411:     \end{nrtc}
        !           412: 
        !           413: \item  FOR APPLICATIONS, ONCE IMPLEMENTED, THE OSI SUITE IS SUPERIOR
        !           414: 
        !           415: \item  FOR NETWORK/TRANSPORT ISSUES, AT PRESENT,
        !           416:        THE INTERNET SUITE IS SUPERIOR
        !           417: \end{nrtc}
        !           418: \end{bwslide}
        !           419: 
        !           420: 
        !           421: \begin{bwslide}
        !           422: \part* {METRICS FOR COMPARISON}\bf
        !           423: 
        !           424: \begin{nrtc}
        !           425: \item  CAN JUDGE A TRANSITION/COEXISTENCE SCHEME USING DIFFERENT
        !           426:        CRITERIA
        !           427: 
        !           428: \item  THE FOUR WE'LL FOCUS ON ARE ALL SUBJECTIVE;
        !           429:     \begin{nrtc}
        !           430:     \item      TECHNICAL SOLUTIONS DO NOT EXIST IN A VACUUM
        !           431: 
        !           432:     \item      THEY MUST BE EVALUATED IN THE CONTEXT OF A TARGET ENVIRONMENT
        !           433:     \end{nrtc}
        !           434: \end{nrtc}
        !           435: \end{bwslide}
        !           436: 
        !           437: 
        !           438: \begin{bwslide}
        !           439: \ctitle        {METRICS FOR COMPARISON (cont.)}
        !           440: 
        !           441: \begin{nrtc}
        !           442: \item  PERFORMANCE:
        !           443:     \begin{nrtc}
        !           444:     \item      THROUGHPUT, LATENCY
        !           445: 
        !           446:     \item      EFFECT ON OTHER APPLICATIONS
        !           447:     \end{nrtc}
        !           448: 
        !           449: \item  FLEXIBILITY:
        !           450:     \begin{nrtc}
        !           451:     \item      RANGE OF APPLICABILITY
        !           452:     \end{nrtc}
        !           453: \end{nrtc}
        !           454: \end{bwslide}
        !           455: 
        !           456: 
        !           457: \begin{bwslide}
        !           458: \ctitle        {METRICS FOR COMPARISON (cont.)}
        !           459: 
        !           460: \begin{nrtc}
        !           461: \item  TRANSPARENCY:
        !           462:     \begin{nrtc}
        !           463:     \item      USAGE CONTINUITY
        !           464: 
        !           465:     \item      SEAMLESS USER INTERFACE
        !           466:     \end{nrtc}
        !           467: 
        !           468: \item  AMENABILITY:
        !           469:     \begin{nrtc}
        !           470:     \item      MANAGEABILITY
        !           471:     \end{nrtc}
        !           472: \end{nrtc}
        !           473: \end{bwslide}
        !           474: 
        !           475: 
        !           476: \begin{bwslide}
        !           477: \ctitle        {SEVERAL CANDIDATES}
        !           478: 
        !           479: \begin{nrtc}
        !           480: \item  PROTOCOL-BASED APPROACHES
        !           481:     \begin{nrtc}
        !           482:     \item      DUAL STACK
        !           483: 
        !           484:     \item      APPLICATION GATEWAYS
        !           485: 
        !           486:     \item      TRANSPORT GATEWAYS
        !           487:     \end{nrtc}
        !           488: 
        !           489: \item  SERVICE-BASED APPROACHES
        !           490:     \begin{nrtc}
        !           491:     \item      TRANSPORT-SERVICE BRIDGES
        !           492: 
        !           493:     \item      NETWORK TUNNELS
        !           494:     \end{nrtc}
        !           495: 
        !           496: \item  NONE OF THESE TECHNIQUES ARE SPECIFIC TO THE PROBLEM OF
        !           497:     \begin{nrtc}
        !           498:     \item      INTERNET $\mapsto$ OSI
        !           499:     \end{nrtc}
        !           500: \end{nrtc}
        !           501: \end{bwslide}
        !           502: 
        !           503: 
        !           504: \begin{bwslide}
        !           505: \part  {PROTOCOL-BASED APPROACHES}\bf
        !           506: 
        !           507: \begin{nrtc}
        !           508: \item  THE ``STANDARD'' METHODS USED TO INTERCONNECT DIFFERENT
        !           509:        PROTOCOL STACKS
        !           510: 
        !           511: \item  THESE EMPHASIZE THE PROTOCOLS IN EACH STACK
        !           512: 
        !           513: \item  HENCE THEY REINFORCE THE BOUNDARIES BETWEEN TCP/IP AND OSI
        !           514: \end{nrtc}
        !           515: \end{bwslide}
        !           516: 
        !           517: 
        !           518: \begin{bwslide}
        !           519: \part* {DUAL STACK}\bf
        !           520: 
        !           521: \begin{nrtc}
        !           522: \item  PUT BOTH PROTOCOL SUITES IN ALL HOSTS
        !           523: 
        !           524: \item  WORKS WELL, IF YOU CAN CHANGE EVERYTHING ON THE NETWORK
        !           525: \begin{quote}\em
        !           526: ``Nice work, if you can get it.''\\ \raggedleft
        !           527: -- Groucho Marx, Monkey Business, Paramount Pictures (1931)
        !           528: \end{quote}
        !           529: \end{nrtc}
        !           530: \end{bwslide}
        !           531: 
        !           532: 
        !           533: \begin{bwslide}
        !           534: \ctitle        {DUAL STACK (cont.)}
        !           535: 
        !           536: \vskip.5in
        !           537: \diagram[p]{figureT-1}
        !           538: \end{bwslide}
        !           539: 
        !           540: 
        !           541: \begin{bwslide}
        !           542: \ctitle        {TALKING TO UNI-STACK HOSTS}
        !           543: 
        !           544: \begin{nrtc}
        !           545: \item  QUESTION: HOW TO DECIDE WHICH APPLICATION INSTANCE,
        !           546:     \begin{nrtc}
        !           547:     \item      APPL-$\alpha$ OR APPL-$\gamma$,
        !           548:     \end{nrtc}
        !           549:        TO USE?
        !           550: 
        !           551: \item  TWO ANSWERS:
        !           552:     \begin{nrtc}
        !           553:     \item      DEPEND ON THE USER TO KNOW AND INVOKE THE RIGHT PROGRAM
        !           554: 
        !           555:     \item      DEVELOP A GENERIC APPLICATION WHICH SUPPORTS BOTH CLASSES
        !           556:     \end{nrtc}
        !           557: 
        !           558: \item  IN THE LATTER CASE, NEED AN UP-TO-DATE DIRECTORY TO DO THIS RELIABLY
        !           559: \end{nrtc}
        !           560: \end{bwslide}
        !           561: 
        !           562: 
        !           563: \begin{bwslide}
        !           564: \ctitle        {GENERIC APPLICATION INSTANCE}
        !           565: 
        !           566: \vskip.5in
        !           567: \diagram[p]{figureT-6}
        !           568: \end{bwslide}
        !           569: 
        !           570: 
        !           571: \begin{bwslide}
        !           572: \ctitle        {AN IMPLEMENTATION OF DUAL-STACK}
        !           573: 
        !           574: \begin{nrtc}
        !           575: \item  ENVIRONMENT: \unix/~SVR3 (STREAMS)
        !           576: 
        !           577: \item  ACCESS TO LOWER-LAYER PROTOCOLS VIA TRANSPORT LAYER INTERFACE (TLI)
        !           578: 
        !           579: \item  NOTE THAT ALTHOUGH TLI PROVIDES A UNIFORM INTERFACE,
        !           580:        IT DOES NOT PROVIDE A UNIFORM SERVICE:
        !           581:     \begin{nrtc}
        !           582:     \item      PACKET- vs. STREAM-ORIENTATION
        !           583: 
        !           584:     \item      GRACEFUL RELEASE
        !           585: 
        !           586:     \item      EXPEDITED vs. URGENT DATA
        !           587: 
        !           588:     \item      ADDRESSING
        !           589:     \end{nrtc}
        !           590: \end{nrtc}
        !           591: \end{bwslide}
        !           592: 
        !           593: 
        !           594: \begin{bwslide}
        !           595: \ctitle        {GENERIC APPLICATION INSTANCE}
        !           596: 
        !           597: \vskip.5in
        !           598: \diagram[p]{figureT-11}
        !           599: \end{bwslide}
        !           600: 
        !           601: 
        !           602: \begin{bwslide}
        !           603: \ctitle        {SCORECARD}
        !           604: 
        !           605: \begin{nrtc}
        !           606: \item  PERFORMANCE: NO DEGRADATION
        !           607: 
        !           608: \item  FLEXIBILITY: GOOD
        !           609: 
        !           610: \item  TRANSPARENCY:
        !           611:     \begin{nrtc}
        !           612:     \item      ASSUMING REMOTE SYSTEM SUPPORTS AT LEAST ONE OF THE PROTOCOL
        !           613:                STACKS, THEN HIGH TRANSPARENCY BY USING COMMON SERVICE
        !           614:                INTERFACE
        !           615:     \end{nrtc}
        !           616: 
        !           617: \item  AMENABILITY:
        !           618:     \begin{nrtc}
        !           619:     \item      BOTH END- AND INTERMEDIATE-SYSTEMS MUST RUN BOTH PROTOCOLS
        !           620: 
        !           621:     \item      INTRODUCES ADMINISTRATIVE PROBLEMS AS THERE ARE NOW TWO
        !           622:                LOGICAL NETWORKS
        !           623:        \begin{nrtc}
        !           624:        \item   MANAGEMENT OF BOTH \underline{PLUS} CONTENTION BETWEEN THEM
        !           625:        \end{nrtc}
        !           626:     \end{nrtc}
        !           627: \end{nrtc}
        !           628: \end{bwslide}
        !           629: 
        !           630: 
        !           631: \begin{bwslide}
        !           632: \part* {APPLICATION GATEWAYS}\bf
        !           633: 
        !           634: \begin{nrtc}
        !           635: \item  A WELL-KNOWN, BUT LITTLE-UNDERSTOOD TECHNOLOGY
        !           636:     \begin{nrtc}
        !           637:     \item      USED IN MESSAGE HANDLING QUITE A BIT
        !           638:     \end{nrtc}
        !           639: 
        !           640: \item  MOST ARE QUITE TERRIBLE
        !           641: \begin{quote}\em
        !           642: ``Sometimes when you try to turn an apple into an orange you get back a
        !           643: lemon.''\\ \raggedleft
        !           644: -- Michael Padlipsky, The Elements of Networking Style (1985)
        !           645: \end{quote}
        !           646: \end{nrtc}
        !           647: \end{bwslide}
        !           648: 
        !           649: 
        !           650: \begin{bwslide}
        !           651: \ctitle        {APPLICATION GATEWAYS (cont.)}
        !           652: 
        !           653: \vskip.5in
        !           654: \diagram[p]{figureT-2}
        !           655: \end{bwslide}
        !           656: 
        !           657: 
        !           658: \begin{bwslide}
        !           659: \ctitle        {IMPERFECT MAPPINGS}
        !           660: 
        !           661: \begin{nrtc}
        !           662: \item  BECAUSE THEY ARE AT THE HIGHEST LAYER IN THE STACK,
        !           663:        APPLICATION GATEWAYS TEND TO PERFORM SEMANTIC MAPPINGS
        !           664: 
        !           665: \item  THESE ARE ACCOMPANIED BY A LOSS OF INFORMATION
        !           666: 
        !           667: \item  SOMETIMES THE LOSS IS ONLY ANNOYING
        !           668:     \begin{nrtc}
        !           669:     \item      e.g., ``FUNNY LOOKING'' MAIL ADDRESSES
        !           670:     \end{nrtc}
        !           671: 
        !           672: \item  SOMETIMES THE LOSS IS CATASTROPHIC
        !           673:     \begin{nrtc}
        !           674:     \item      e.g., ROUTING LOOPS
        !           675:     \end{nrtc}
        !           676: \end{nrtc}
        !           677: \end{bwslide}
        !           678: 
        !           679: 
        !           680: \begin{bwslide}
        !           681: \ctitle        {AN IMPLEMENATION OF APPLICATION-GATEWAY}
        !           682: 
        !           683: \begin{nrtc}
        !           684: \item  TWO KINDS OF IMPLEMENATIONS
        !           685: 
        !           686: \item  STAGING (TRUE STORE-AND-FORWARD):
        !           687:     \begin{nrtc}
        !           688:     \item      TOP-LEVEL PROTOCOL TRANSACTIONS ARE GROUPED AT THE GATEWAY
        !           689: 
        !           690:     \item      REQUIRES LOCAL STORAGE, BUT MAY PERMIT BETTER MAPPINGS
        !           691:     \end{nrtc}
        !           692: 
        !           693: \item  IN-SITU (VIRTUAL END-TO-END):
        !           694:     \begin{nrtc}
        !           695:     \item      NO PROTOCOL TRANSACTIONS ARE GROUPED
        !           696: 
        !           697:     \item      MAPPINGS ARE ``ON THE FLY''\\ (AND PERHAPS LESS PRECISE)
        !           698: 
        !           699:     \item      END-TO-END RESPONSE IS FASTER
        !           700:     \end{nrtc}
        !           701: \end{nrtc}
        !           702: \end{bwslide}
        !           703: 
        !           704: 
        !           705: \begin{bwslide}
        !           706: \ctitle        {INVOKING THE GATEWAY}
        !           707: 
        !           708: \vskip1.5in
        !           709: \begin{verbatim}
        !           710: % ftp file-gateway
        !           711: Name (file-gateway:asterix): obelix@osi-host
        !           712: Password:
        !           713: \end{verbatim}
        !           714: \end{bwslide}
        !           715: 
        !           716: 
        !           717: \begin{bwslide}
        !           718: \ctitle        {A STAGING IMPLEMENTATION}
        !           719: 
        !           720: \vskip.5in
        !           721: \diagram[p]{figureT-12}
        !           722: \end{bwslide}
        !           723: 
        !           724: 
        !           725: \begin{bwslide}
        !           726: \ctitle        {AN IN-SITU IMPLEMENTATION}
        !           727: 
        !           728: \vskip.5in
        !           729: \diagram[p]{figureT-13}
        !           730: \end{bwslide}
        !           731: 
        !           732: 
        !           733: \begin{bwslide}
        !           734: \ctitle        {SCORECARD}
        !           735: 
        !           736: \begin{nrtc}
        !           737: \item  PERFORMANCE: USUALLY POOR, BUT ACCEPTABLE FOR STORE-AND-FORWARD
        !           738:        APPLICATIONS
        !           739:     \begin{nrtc}
        !           740:     \item      TYPICALLY ALSO INTRODUCES ADDITIONAL NETWORK TRAFFIC
        !           741:     \end{nrtc}
        !           742: 
        !           743: \item  FLEXIBILITY: NONE; EACH A-GWY IS A SPECIAL-PURPOSE SOFTWARE BOX
        !           744: 
        !           745: \item  TRANSPARENCY: 
        !           746:     \begin{nrtc}
        !           747:     \item      TO SERVICE: OFTEN LOSES SIGNIFICANT FUNCTIONALITY
        !           748: 
        !           749:     \item      TO USERS: POSSIBLE, BUT NOT LIKELY (e.g., IN AN FTAM/FTP A-GWY,
        !           750:                USERS EMBED HOSTNAMES IN FILENAMES)
        !           751:     \end{nrtc}
        !           752: 
        !           753: \item  AMENABILITY:
        !           754:     \begin{nrtc}
        !           755:     \item      REQUIRES NO END-SYSTEM MODIFICATION
        !           756: 
        !           757:     \item      MAY INTRODUCE ADMINISTRATIVE PROBLEMS
        !           758:     \end{nrtc}
        !           759: \end{nrtc}
        !           760: \end{bwslide}
        !           761: 
        !           762: 
        !           763: \begin{bwslide}
        !           764: \part* {TRANSPORT GATEWAYS}\bf
        !           765: 
        !           766: \begin{nrtc}
        !           767: \item  IDEA: GATEWAY AT THE TRANSPORT LAYER SO AS TO AVOID NEEDING
        !           768:        MULTIPLE APPLICATION GATEWAYS
        !           769: \begin{quote}\em
        !           770: ``We could do it, but it would be wrong.''\\ \raggedleft
        !           771: -- Richard Nixon, The Watergate Tapes (1974)
        !           772: \end{quote}
        !           773: 
        !           774: \item  ALTHOUGH THE OSI (TP4) AND INTERNET (TCP) TRANSPORT PROTOCOLS DIFFER,
        !           775:        THE SERVICE IS QUITE SIMILAR
        !           776: 
        !           777: \item  HENCE, IT IS TECHNICALLY FEASIBLE TO PERFORM THE MAPPINGS
        !           778:     \begin{nrtc}
        !           779:     \item      (ALTHOUGH IT'S A LOT OF HARD WORK)
        !           780:     \end{nrtc}
        !           781: \end{nrtc}
        !           782: \end{bwslide}
        !           783: 
        !           784: 
        !           785: \begin{bwslide}
        !           786: \ctitle        {TRANSPORT GATEWAYS (cont.)}
        !           787: 
        !           788: \vskip.5in
        !           789: \diagram[p]{figureT-14}
        !           790: \end{bwslide}
        !           791: 
        !           792: 
        !           793: \begin{bwslide}
        !           794: \ctitle        {THE OBVIOUS QUESTION}
        !           795: 
        !           796: \begin{nrtc}
        !           797: \item  WHAT APPLICATION DO YOU RUN WHEN USING THIS?
        !           798:     \begin{nrtc}
        !           799:     \item      CAN'T RUN INTERNET APPLICATIONS IN THE OSI NETWORK,
        !           800:                SINCE THE TRANSPORT GATEWAY YIELDS OSI TRANSPORT SEMANTICS
        !           801: 
        !           802:     \item      CAN'T RUN OSI APPLICATIONS IN THE INTERNET NETWORK,
        !           803:                SINCE THE TRANSPORT GATEWAY YIELDS INTERNET TRANSPORT SEMANTICS
        !           804:     \end{nrtc}
        !           805: 
        !           806: \item  THIS APPROACH FAILS BECAUSE IT PRESENTS DIFFERENT SERVICE SEMANTICS
        !           807:        IN EACH NETWORK
        !           808: \end{nrtc}
        !           809: \end{bwslide}
        !           810: 
        !           811: 
        !           812: \begin{bwslide}
        !           813: \part  {SERVICE-BASED APPROACHES}\bf
        !           814: 
        !           815: \begin{nrtc}
        !           816: \item  BY THE TIME OSI-BASED NETWORKS ARE TRULY WIDESPREAD,
        !           817:        TCP/IP-BASED NETWORKS WILL ALREADY OFFER A MIX OF SERVICES:
        !           818:     \begin{nrtc}
        !           819:     \item      SUCH AS FTAM AND MHS, IN ADDITION TO FTP AND SMTP
        !           820:     \end{nrtc}
        !           821: 
        !           822: \item  IN OTHER WORDS, PERHAPS THE TRANSITION TO OSI BEGINS WITH NEW
        !           823:        APPLICATIONS ON HOSTS AND NO CHANGES TO THE NETWORK
        !           824: \end{nrtc}
        !           825: \end{bwslide}
        !           826: 
        !           827: 
        !           828: \begin{bwslide}
        !           829: \ctitle        {WOULD THIS REALLY HAPPEN?}
        !           830: 
        !           831: \begin{nrtc}
        !           832: \item  RECALL THAT USERS ARE INTERESTED IN \underline{SERVICES} NOT
        !           833:        \underline{PROTOCOLS}
        !           834: 
        !           835: \item  THE OSI APPLICATIONS ARE MUCH RICHER THAN THEIR INTERNET COUNTERPARTS
        !           836: 
        !           837: \item  IN CONTRAST, AT THE LOWER-LAYERS THE INTERNET SUITE ``WORKS BETTER''
        !           838:     \begin{nrtc}
        !           839:     \item      AS SUCH, IT IS UNLIKELY TO BE REPLACED BY THE OSI LOWER-LAYERS
        !           840:                FOR QUITE SOME TIME
        !           841:     \end{nrtc}
        !           842: \end{nrtc}
        !           843: \end{bwslide}
        !           844: 
        !           845: 
        !           846: \begin{bwslide}
        !           847: \ctitle        {OBSERVATION}
        !           848: 
        !           849: \begin{nrtc}
        !           850: \item  GIVEN THE ABOVE ASSUMPTION, IT SHOULD BE NOTED THAT:
        !           851:     \begin{nrtc}
        !           852:     \item      WE HAVE TWO COMMUNITIES USING THE SAME APPLICATIONS
        !           853:                (OSI), AND
        !           854: 
        !           855:     \item      ONLY THE UNDERLYING ``TS-STACK'' WILL DIFFER BETWEEN THE TWO:
        !           856:        \begin{nrtc}
        !           857:        \item   IN THE OSI COMMUNITY: TP4/CLNP/$\ldots$
        !           858: 
        !           859:        \item   IN THE TCP COMMUNITY: RFC1006/TCP/IP/$\ldots$
        !           860:        \end{nrtc}
        !           861:     \end{nrtc}
        !           862: 
        !           863: \item  THIS LEADS US TO POSTULATE AN INTERESTING COEXISTENCE
        !           864:        STRATEGY:
        !           865:     \begin{nrtc}
        !           866:     \item      LET'S RUN OSI APPLICATIONS, END-TO-END, BETWEEN THE TWO
        !           867:     \end{nrtc}
        !           868: 
        !           869: \item  IN A SENSE, THIS IS A HYBRID OF THE TWO PREVIOUS APPROACHES,
        !           870:        INTENDED TO MINIMIZE THE DISADVANTAGES OF EACH
        !           871:     \begin{nrtc}
        !           872:        \item   SAME APPLICATION PROTOCOL,\\
        !           873:                BUT DIFFERENT UNDERYLING LAYERS
        !           874:     \end{nrtc}
        !           875: \end{nrtc}
        !           876: \end{bwslide}
        !           877: 
        !           878: 
        !           879: \begin{bwslide}
        !           880: \part* {TRANSPORT-SERVICE BRIDGES}\bf
        !           881: 
        !           882: \begin{nrtc}
        !           883: \item  INTRODUCE A TRANSPORT ENTITY CALLED THE ``TS-BRIDGE''
        !           884: \begin{quote}\em
        !           885: ``Users are interested in services, not protocols.''\\ \raggedleft
        !           886: -- Marshall Rose, NYSERNet, Inc.
        !           887: \end{quote}
        !           888: 
        !           889: \item  THE TS-BRIDGE ``COPIES'' SERVICE PRIMITIVES FROM ONE TS-STACK TO THE
        !           890:        OTHER, e.g.:
        !           891:     \begin{nrtc}
        !           892:     \item      UPON RECEIVING A T-CONNECT.INDICATION PRIMITIVE FROM ONE
        !           893:                TS-STACK,
        !           894: 
        !           895:     \item      IT ISSUES A T-CONNECT.REQUEST PRIMITIVE TO THE OTHER TS-STACK
        !           896:     \end{nrtc}
        !           897: 
        !           898: \item  AS DISCUSSED EARLIER, THIS TECHNOLOGY IS USED FOR CONNECTIVITY BETWEEN
        !           899:        DIFFERENT OSI COMMUNITIES
        !           900: \end{nrtc}
        !           901: \end{bwslide}
        !           902: 
        !           903: 
        !           904: \begin{bwslide}
        !           905: \ctitle        {TRANSPORT-SERVICE BRIDGES (cont.)}
        !           906: 
        !           907: \vskip.5in
        !           908: \diagram[p]{figureT-9}
        !           909: \end{bwslide}
        !           910: 
        !           911: 
        !           912: \begin{bwslide}
        !           913: \ctitle        {CONS vs. CLNS CONNECTIVITY}
        !           914: 
        !           915: \vskip.5in
        !           916: \diagram[p]{figureT-19}
        !           917: \end{bwslide}
        !           918: 
        !           919: 
        !           920: \begin{bwslide}
        !           921: \ctitle        {THE TS-BRIDGE AND THE OSI MODEL\\ (REVIEW)}
        !           922: 
        !           923: \begin{nrtc}
        !           924: \item  THE TS-BRIDGE IS A LEVEL-FOUR ROUTER
        !           925: 
        !           926: \item  POTENTIAL PROBLEMS:
        !           927:     \begin{nrtc}
        !           928:     \item      THE TS-BRIDGE MAINTAINS STATE AS TO THE EXISTING CONNECTIONS
        !           929: 
        !           930:     \item      TWO CHECKSUMS, AND NEITHER REALLY END-TO-END
        !           931: 
        !           932:     \item      \underline{MAY} THWART SOPHISTICATED BACK-PRESSURE TECHNIQUES
        !           933:     \end{nrtc}
        !           934: \end{nrtc}
        !           935: \end{bwslide}
        !           936: 
        !           937: 
        !           938: \begin{bwslide}
        !           939: \ctitle        {AN IMPLEMENTATION OF THE TS-BRIDGE}
        !           940: 
        !           941: \begin{nrtc}
        !           942: \item  FIRST DEMONSTRATION IN FEBRUARY, 1988
        !           943:     \begin{nrtc}
        !           944:     \item      TP4/CLNP to RFC1006/TCP
        !           945:     \end{nrtc}
        !           946: 
        !           947: \item  ANOTHER IMPLEMENTATION IN EUROPE IS HANDLING
        !           948:     \begin{nrtc}
        !           949:     \item      TP0/X.25 to RFC1006/TCP
        !           950:     \end{nrtc}
        !           951: \end{nrtc}
        !           952: \end{bwslide}
        !           953: 
        !           954: 
        !           955: \begin{bwslide}
        !           956: \ctitle        {SCORECARD}
        !           957: 
        !           958: \begin{nrtc}
        !           959: \item  PERFORMANCE: FAIR; WHEN TS-BRIDGE IS MADE INTO A KERNEL-RESIDENT
        !           960:        STREAMS MODULE IT SHOULD IMPROVE DRAMATICALLY
        !           961: 
        !           962: \item  FLEXIBILITY: HIGH; INDEPENDENT OF ANY APPLICATION
        !           963: 
        !           964: \item  TRANSPARENCY: TOTAL
        !           965: 
        !           966: \item  AMENABILITY:
        !           967:     \begin{nrtc}
        !           968:     \item      TCP END-SYSTEMS MUST RUN ``NEW'' PROTOCOLS
        !           969:        \begin{nrtc}
        !           970:        \item   BUT, NO MODIFICATIONS REQUIRED TO END-SYSTEM KERNELS
        !           971:        \end{nrtc}
        !           972: 
        !           973:     \item      MAY INTRODUCE ADMINISTRATIVE PROBLEMS
        !           974:     \end{nrtc}
        !           975: \end{nrtc}
        !           976: \end{bwslide}
        !           977: 
        !           978: 
        !           979: \begin{bwslide}
        !           980: \part* {NETWORK TUNNELS}\bf
        !           981: 
        !           982: \begin{nrtc}
        !           983: \item  IDEA: ENCAPSULATE CLNP INSIDE OF IP, TREATING IP AS SIMPLY A DATA LINK
        !           984:        PROTOCOL
        !           985: \begin{quote}\em
        !           986: ``Encapsulation complies with the layering concept, but violates the notion
        !           987: of absolute levels.''\\ \raggedleft
        !           988: -- Danny Cohen and Jon Postel, ``The ISO Reference Model and Other Protocol
        !           989: Architectures'' (1983)
        !           990: \end{quote}
        !           991: 
        !           992: \item  NS-TUNNEL PERFORMS AS A ROUTER, REMOVING ONE DATA LINK HEADER AND
        !           993:        ADDING ANOTHER
        !           994: 
        !           995: \item  METHOD SPECIFIED IN [RFC1070]
        !           996: 
        !           997: \item  ADDRESS MAPPINGS SPECIFIED IN [RFC1069] 
        !           998: \end{nrtc}
        !           999: \end{bwslide}
        !          1000: 
        !          1001: 
        !          1002: \begin{bwslide}
        !          1003: \ctitle        {TUNNELING}
        !          1004: 
        !          1005: \vskip.5in
        !          1006: \diagram[p]{figureT-18}
        !          1007: \end{bwslide}
        !          1008: 
        !          1009: 
        !          1010: \begin{bwslide}
        !          1011: \ctitle        {NETWORK TUNNELS}
        !          1012: 
        !          1013: \vskip.5in
        !          1014: \diagram[p]{figureT-10}
        !          1015: \end{bwslide}
        !          1016: 
        !          1017: 
        !          1018: \begin{bwslide}
        !          1019: \ctitle        {INTERESTING FEATURES}
        !          1020: 
        !          1021: \begin{nrtc}
        !          1022: \item  NO STATE MAINTAINED BY NS-TUNNEL
        !          1023: 
        !          1024: \item  A TRUE END-TO-END CHECKSUM
        !          1025: \end{nrtc}
        !          1026: \end{bwslide}
        !          1027: 
        !          1028: 
        !          1029: \begin{bwslide}
        !          1030: \ctitle        {POTENTIAL PROBLEMS}
        !          1031: 
        !          1032: \begin{nrtc}
        !          1033: \item  REQUIRES COMMON HIGHER-LEVEL PROTOCOLS (TRANSPORT AND ABOVE) ON BOTH
        !          1034:        END-SYSTEMS, BUT DOES NOT REQUIRE ALL INTERVENING ROUTERS TO USE THE
        !          1035:        SAME NETWORK PROTOCOL
        !          1036: 
        !          1037: \item  THE TCP END-SYSTEM IMPLEMENTATION CHOICES ARE SIMILAR TO NETBIOS OVER
        !          1038:        TCP [RFC1001/1002]
        !          1039: \end{nrtc}
        !          1040: \end{bwslide}
        !          1041: 
        !          1042: 
        !          1043: \begin{bwslide}
        !          1044: \ctitle        {AN IMPLEMENATION OF AN NS-TUNNEL}
        !          1045: 
        !          1046: \begin{nrtc}
        !          1047: \item  HAVEN'T SEE ANY YET
        !          1048:     \begin{nrtc}
        !          1049:     \item      BUT WILL BE IN 4.4BSD UNIX
        !          1050:     \end{nrtc}
        !          1051: 
        !          1052: \item  NEED A LOT OF CLNP-BASED NETWORKS BEFORE THIS IS OF USE
        !          1053: 
        !          1054: \item  SO THIS WILL HAPPEN AT THE END OF THE TRANSITION PERIOD
        !          1055: \end{nrtc}
        !          1056: \end{bwslide}
        !          1057: 
        !          1058: 
        !          1059: \begin{bwslide}
        !          1060: \ctitle        {SCORECARD}
        !          1061: 
        !          1062: \begin{nrtc}
        !          1063: \item  PERFORMANCE: NO WORSE THAN TYPICAL CLNP-ROUTER (AND PROBABLY A LOT
        !          1064:        BETTER TOO!)
        !          1065: 
        !          1066: \item  FLEXIBILITY: HIGH (INDEPENDENT OF ANY APPLICATION)
        !          1067: 
        !          1068: \item  TRANSPARENCY: TOTAL
        !          1069: 
        !          1070: \item  AMENABILITY: TCP END-SYSTEMS MUST RUN BOTH TRANSPORT PROTOCOLS
        !          1071: \end{nrtc}
        !          1072: \end{bwslide}
        !          1073: 
        !          1074: 
        !          1075: \begin{bwslide}
        !          1076: \part  {EXAMPLES}\bf
        !          1077: 
        !          1078: \begin{nrtc}
        !          1079: \item  DoD OSI IMPLEMENTATION PLAN
        !          1080: 
        !          1081: \item  GENERIC EXAMPLE
        !          1082: 
        !          1083: \item  CONCLUSIONS
        !          1084: \end{nrtc}
        !          1085: \end{bwslide}
        !          1086: 
        !          1087: 
        !          1088: \begin{bwslide}
        !          1089: \part* {DoD OSI\\ IMPLEMENTATION PLAN}\bf
        !          1090: 
        !          1091: \begin{nrtc}
        !          1092: \item  IMPLEMENT CAPABILITY TO USE OSI IN DoD INTERNETWORK ENVIRONMENT
        !          1093:     \begin{nrtc}
        !          1094:     \item      OSI-POSIX PROJECT
        !          1095:     \end{nrtc}
        !          1096: 
        !          1097: \item  PROVIDE THE CAPABILITY FOR DoD AND OSI PROTOCOLS TO INTEROPERATE
        !          1098:     \begin{nrtc}
        !          1099:     \item      FTAM-FTP GATEWAY
        !          1100: 
        !          1101:     \item      MHS-SMTP GATEWAY
        !          1102:     \end{nrtc}
        !          1103: \end{nrtc}
        !          1104: \end{bwslide}
        !          1105: 
        !          1106: 
        !          1107: \begin{bwslide}
        !          1108: \ctitle        {OSI-POSIX PROJECT}
        !          1109: 
        !          1110: \begin{nrtc}
        !          1111: \item  GOAL: ACCELLERATE THE UBIQUITY OF OSI
        !          1112: 
        !          1113: \item  APPROACH: OPENLY AVAILABLE, COMPLETE OSI IMPLEMENTATION FOR NEXT MAJOR
        !          1114:        RELEASE OF BERKELEY \unix/
        !          1115: 
        !          1116: \item  FOR MORE DETAILS:
        !          1117: \begin{quote}
        !          1118: OSI PROTOCOLS WITHIN AN OPENLY AVAILABLE, POSIX-CONFORMANT, BERKELEY UNIX
        !          1119: ENVIRONMENT
        !          1120: \end{quote}
        !          1121: APPEARING IN ConneXions, OCTOBER, 1988
        !          1122: \end{nrtc}
        !          1123: \end{bwslide}
        !          1124: 
        !          1125: 
        !          1126: \begin{bwslide}
        !          1127: \diagram[p]{figureT-15}
        !          1128: \end{bwslide}
        !          1129: 
        !          1130: 
        !          1131: \begin{bwslide}
        !          1132: \diagram[p]{figureT-16}
        !          1133: \end{bwslide}
        !          1134: 
        !          1135: 
        !          1136: \begin{bwslide}
        !          1137: \part* {GENERIC EXAMPLE}\bf
        !          1138: 
        !          1139: \begin{nrtc}
        !          1140: \item  TWO PRONGS:
        !          1141:     \begin{nrtc}
        !          1142:     \item      FAVOR USE OF OSI APPLICATIONS OVER TCP ON LAN MESH
        !          1143: 
        !          1144:     \item      LOCATE APPLICATION GATEWAYS AND A TS-BRIDGE ON ALL NODES
        !          1145:                WITH WAN ATTACHMENETS
        !          1146:     \end{nrtc}
        !          1147: 
        !          1148: \item  AWAIT OSI LOWER-LAYERS TO BECOME COMPETITIVE
        !          1149: \end{nrtc}
        !          1150: \end{bwslide}
        !          1151: 
        !          1152: 
        !          1153: \begin{bwslide}
        !          1154: \ctitle        {GENERIC EXAMPLE (cont.)}
        !          1155: 
        !          1156: \begin{nrtc}
        !          1157: \item  EACH ATTACHMENT LOCUS SHOULD SUPPORT COEXISTENCE SERVICES
        !          1158: 
        !          1159: \item  IF RESOURCES PERMIT, SELECT ONE OTHER SYSTEM TO SUPPORT THESE
        !          1160:        SERVICES FOR USE BY LOCAL UNI-STACK HOSTS
        !          1161: 
        !          1162: \item  THIS ``COVERS ALL BASES'' BY HANDLING ALL POSSIBLE OSI COMBINATIONS
        !          1163:        WITH A BIT OF EXTRA REDUNDANCY
        !          1164: 
        !          1165: \item  MIGHT REQUIRE A BIT OF SOPHISTICATED USE FROM THE DIRECTORY
        !          1166: \end{nrtc}
        !          1167: \end{bwslide}
        !          1168: 
        !          1169: 
        !          1170: \begin{bwslide}
        !          1171: \ctitle        {A LAN OF MANY COLORS}
        !          1172: 
        !          1173: \vskip.5in
        !          1174: \diagram[p]{figureT-17}
        !          1175: \end{bwslide}
        !          1176: 
        !          1177: 
        !          1178: \begin{bwslide}
        !          1179: \part* {CONCLUSIONS}\bf
        !          1180: 
        !          1181: \begin{quote}\em
        !          1182: ``Optimality differs according to context.''\\ \raggedleft
        !          1183: -- Michael Padlipsky, The Elements of Networking Style (1985)
        !          1184: \end{quote}
        !          1185: \end{bwslide}
        !          1186: 
        !          1187: 
        !          1188: \begin{bwslide}
        !          1189: \ctitle        {CONCLUSIONS (cont.)}
        !          1190: 
        !          1191: \begin{nrtc}
        !          1192: \item  TCP/IP-BASED NETWORKS WILL OFFER OSI APPLICATIONS
        !          1193: 
        !          1194: \item  COEXISTENCE IN THE SHORT TERM:
        !          1195:     \begin{nrtc}
        !          1196:     \item      TS-BRIDGE MINIMIZES SOFTWARE INVESTMENT
        !          1197:     \end{nrtc}
        !          1198: 
        !          1199: \item  COEXISTENCE IN THE LONG TERM:
        !          1200:     \begin{nrtc}
        !          1201:     \item      NS-TUNNEL MAXIMIZES PERFORMANCE AND ROBUSTNESS
        !          1202:     \end{nrtc}
        !          1203: 
        !          1204: \item  IF/WHEN THERE ARE NO MORE TCP/IP-BASED NETWORKS, THEN THE
        !          1205:        COEXISTENCE PERIOD IS OVER, AND TRANSITION IS A NON-ISSUE!
        !          1206: \end{nrtc}
        !          1207: \end{bwslide}

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