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1.1     ! root        1: % run this through LaTeX with the appropriate wrapper
        !             2: 
        !             3: \dotopic{TRANSITION AND\\ COEXISTENCE\\ WITH TCP/IP}
        !             4: 
        !             5: 
        !             6: \begin{bwslide}
        !             7: \part* {OUTLINE}\bf
        !             8: 
        !             9: \begin{description}
        !            10: \item[PART I:]         MOTIVATION
        !            11: 
        !            12: \item[PART II:]                BACKGROUND
        !            13: 
        !            14: \item[PART III:]       PROTOCOL-BASED APPROACHES
        !            15: 
        !            16: \item[PART IV:]                SERVICE-BASED APPROACHES
        !            17: 
        !            18: \item[PART V:]         EXAMPLES
        !            19: \end{description}
        !            20: \end{bwslide}
        !            21: 
        !            22: 
        !            23: \begin{bwslide}
        !            24: \ctitle        {A BIG ACKNOWLEDGEMENT}
        !            25: 
        !            26: \begin{nrtc}
        !            27: \item  TRANSITION IS MOSTLY SMOKE AND MIRRORS
        !            28: 
        !            29: \item  THE PRACTICAL PERSPECTIVED PRESENTED HERE IS HEAVILY INFLUENCED BY
        !            30:        DISCUSSIONS WITH
        !            31:     \begin{nrtc}
        !            32:     \item      EINAR A.~STEFFERUD (NMA)
        !            33: 
        !            34:     \item      DAVID H.~CROCKER (DEC)
        !            35:     \end{nrtc}
        !            36: \end{nrtc}
        !            37: \end{bwslide}
        !            38: 
        !            39: 
        !            40: \begin{bwslide}
        !            41: \part  {MOTIVATION}\bf
        !            42: 
        !            43: \begin{nrtc}
        !            44: \item  THERE ARE MANY TCP/IP NETWORKS TODAY; THERE WILL BE MORE TOMORROW
        !            45: 
        !            46: \item  BY THE TIME OSI BECOMES A WORTHWHILE OPERATIONAL ALTERNATIVE,
        !            47:        THERE WILL BE MANY MORE TCP/IP NETWORKS THAN THERE ARE TODAY!
        !            48: 
        !            49: \item  PROBLEM: HOW TO PROTECT INSTALLED BASE?
        !            50: 
        !            51: \item  PROBLEM: HOW TO TRANSITION GRACEFULLY?
        !            52: \end{nrtc}
        !            53: \end{bwslide}
        !            54: 
        !            55: 
        !            56: \begin{bwslide}
        !            57: \ctitle        {GROWTH OF TCP/IP}
        !            58: 
        !            59: \begin{nrtc}
        !            60: \item  SALES OF TCP/IP-BASED TECHNOLOGY
        !            61:     \begin{nrtc}
        !            62:     \item      PARTICULARLY IN EUROPE
        !            63:     \end{nrtc}
        !            64:        CONTINUES TO GROW
        !            65: 
        !            66: \item  SEVERAL TECHNICAL AND MARKET ASPECTS CONTRIBUTE TO THIS PHENOMENA:
        !            67:     \begin{nrtc}
        !            68:     \item      SUPERIORITY OF TCP/IP IN LOWER-LAYER CONNECTIVITY
        !            69: 
        !            70:     \item      MATURITY OF TCP/IP PRODUCTS\\ (e.g., RANGE OF PLATFORMS)
        !            71:     \end{nrtc}
        !            72: 
        !            73: \item  ALTHOUGH OSI WILL DOMINATE, IT DOESN'T YET
        !            74: 
        !            75: \item  HENCE, TCP/IP IS BECOMING MORE FIRMLY ENTRENCHED
        !            76: \end{nrtc}
        !            77: \end{bwslide}
        !            78: 
        !            79: 
        !            80: \begin{bwslide}
        !            81: \ctitle        {FEAR AND LOATHING IN THE MARKET}
        !            82: 
        !            83: \begin{nrtc}
        !            84: \item  F.U.D. IN THE MARKETPLACE:
        !            85: \begin{quote}\em
        !            86: ``All marketing is fear, uncertainty, and doubt.''\\ \raggedleft
        !            87: -- Einar Stefferud, Network Management Associates
        !            88: \end{quote}
        !            89: 
        !            90: \item  WHAT THE VENDORS SAY:
        !            91: \begin{quote}\em
        !            92: ``$\ldots$ protect your investment while assuring a path to an OSI
        !            93: future.''\\ \raggedleft
        !            94: -- Vendor A
        !            95: \end{quote}
        !            96: AND
        !            97: \begin{quote}\em
        !            98: ``$\ldots$ plans for a smooth, painless guaranteed migration to OSI standards
        !            99: as they are approved.''\\ \raggedleft
        !           100: --Vendor B
        !           101: \end{quote}
        !           102: AND
        !           103: \begin{quote}\em
        !           104: ``Once you've scrapped your existing production networks,
        !           105: come to us for OSI.
        !           106: It will be wonderful!''\\ \raggedleft
        !           107: --Vendor C
        !           108: \end{quote}
        !           109: \end{nrtc}
        !           110: \end{bwslide}
        !           111: 
        !           112: 
        !           113: \begin{bwslide}
        !           114: \ctitle        {THE SAD TRUTH}
        !           115: 
        !           116: \begin{quote}\em
        !           117: ``You can't win, and you can't quit, but you \underline{can} reduce the
        !           118: pain.''\\ \raggedleft
        !           119: -- Marshall Rose, PSI, Inc.
        !           120: \end{quote}
        !           121: \end{bwslide}
        !           122: 
        !           123: 
        !           124: \begin{bwslide}
        !           125: \part  {BACKGROUND}\bf
        !           126: 
        !           127: \begin{nrtc}
        !           128: \item  CONCEPTS
        !           129: 
        !           130: \item  TERMINOLOGY
        !           131: 
        !           132: \item  HISTORY
        !           133: 
        !           134: \item  METRICS FOR COMPARISON
        !           135: \end{nrtc}
        !           136: \end{bwslide}
        !           137: 
        !           138: 
        !           139: \begin{bwslide}
        !           140: \ctitle        {THE FUNDAMENTAL ASSUMPTION}
        !           141: 
        !           142: \begin{nrtc}
        !           143: \item  TCP/IP IS HERE TODAY, WIDELY INSTALLED, AND USEFUL
        !           144: 
        !           145: \item  OSI WILL EVENTUALLY REPLACE TCP/IP AS THE OFF-THE-SHELF TECHNOLOGY FOR
        !           146:        BUILDING INTEROPERABLE SYSTMS
        !           147: 
        !           148: \item  BOTH WILL BE SIMULTANEOUSLY WIDESPREAD FOR QUITE SOME TIME
        !           149:     \begin{nrtc}
        !           150:     \item      DURING WHICH OSI WILL GAIN DOMINANCE
        !           151:     \end{nrtc}
        !           152: \end{nrtc}
        !           153: \end{bwslide}
        !           154: 
        !           155: 
        !           156: \begin{bwslide}
        !           157: \part* {CONCEPTS}\bf
        !           158: 
        !           159: \begin{nrtc}
        !           160: \item  TRANSITION:
        !           161:     \begin{nrtc}
        !           162:     \item      TO MOVE FROM ONE PROTOCOL SUITE TO ANOTHER
        !           163:     \end{nrtc}
        !           164: 
        !           165: \item  COEXISTENCE:
        !           166:     \begin{nrtc}
        !           167:     \item      TO LIVE TOGETHER WITHOUT HOSTILITY OR CONFLICT DESPITE
        !           168:                DIFFERENCES
        !           169:     \end{nrtc}
        !           170: 
        !           171: \item  MIGRATION:
        !           172:     \begin{nrtc}
        !           173:     \item      TO MOVE BACK AND FORTH, AS THE SEASONS CHANGE
        !           174:     \end{nrtc}
        !           175: \end{nrtc}
        !           176: \end{bwslide}
        !           177: 
        !           178: 
        !           179: \begin{bwslide}
        !           180: \ctitle        {MAPPINGS}
        !           181: 
        !           182: \begin{nrtc}
        !           183: \item  TRANSITION AND COEXISTENCE CAN BE DESCRIBED BY THE MAPPINGS THEY
        !           184:        REQUIRE
        !           185: 
        !           186: \item  SOME MAPPINGS ARE SIMPLE
        !           187:     \begin{nrtc}
        !           188:     \item      i.e., SYNTACTIC CHANGES
        !           189:     \end{nrtc}
        !           190: 
        !           191: \item  SOME MAPPINGS ARE COMPLEX
        !           192:     \begin{nrtc}
        !           193:     \item      i.e., SEMANTIC CHANGES
        !           194:     \end{nrtc}
        !           195: 
        !           196: \item  THE MORE COMPLEX THE MAPPING, THE GREATER THE LOSS OF INFORMATION OR
        !           197:        INTENT
        !           198: \end{nrtc}
        !           199: \end{bwslide}
        !           200: 
        !           201: 
        !           202: \begin{bwslide}
        !           203: \part* {TERMINOLOGY}\bf
        !           204: 
        !           205: \begin{nrtc}
        !           206: \item  WE'LL FAVOR OSI TERMINOLOGY, BUT STILL NEED SOME INTERNET (TCP/IP)
        !           207:        TERMINOLOGY
        !           208: 
        !           209: \item  TWO BASIC TERMS
        !           210:     \begin{nrtc}
        !           211:     \item      GATEWAY: GENERIC TO ANY LEVEL, COMPLEX
        !           212: 
        !           213:     \item      BRIDGE: GENERIC TO ANY LEVEL, SIMPLE
        !           214:     \end{nrtc}
        !           215: \end{nrtc}
        !           216: \end{bwslide}
        !           217: 
        !           218: 
        !           219: \begin{bwslide}
        !           220: \ctitle        {SERVICE SEMANTICS}
        !           221: 
        !           222: \begin{nrtc}
        !           223: \item  STORE-AND-FORWARD
        !           224:     \begin{nrtc}
        !           225:     \item      SERVICE SEMANTICS CARRIED MULTI-HOP VIA FORWARDERS
        !           226:     \end{nrtc}
        !           227: 
        !           228: \item  END-TO-END
        !           229:     \begin{nrtc}
        !           230:     \item      SERVICE SEMANTICS CARRIED FROM ORIGINATOR TO RECIPIENT
        !           231: 
        !           232:     \item      MAY BE SUPPORTED BY AN UNDERYLING STORE-AND-FORWARD SERVICE
        !           233:     \end{nrtc}
        !           234: \end{nrtc}
        !           235: \end{bwslide}
        !           236: 
        !           237: 
        !           238: \begin{bwslide}
        !           239: \ctitle        {SERVICE SEMANTICS (cont.)}
        !           240: 
        !           241: \vskip.5in
        !           242: \diagram[p]{figureT-3}
        !           243: \end{bwslide}
        !           244: 
        !           245: 
        !           246: \begin{bwslide}
        !           247: \ctitle        {PROTOCOL SUITE}
        !           248: 
        !           249: \begin{nrtc}
        !           250: \item  A COLLECTION OF SERVICES AND PROTOCOLS RELATED:
        !           251:     \begin{nrtc}
        !           252:     \item      ADMINISTRATIVELY, BY AN ORGANIZATION\\ (e.g., ISO/IEC); and,
        !           253: 
        !           254:     \item      PHILOSOPHICALLY, BY A REFERENCE MODEL\\ (e.g., the OSIRM)
        !           255:     \end{nrtc}
        !           256: 
        !           257: \item  FOR OUR PURPOSES, THERE ARE ONLY TWO:
        !           258:     \begin{nrtc}
        !           259:     \item      THE OSI SUITE OF PROTOCOLS
        !           260: 
        !           261:     \item      THE INTERNET SUITE OF PROTOCOLS
        !           262:     \end{nrtc}
        !           263: \end{nrtc}
        !           264: \end{bwslide}
        !           265: 
        !           266: 
        !           267: \begin{bwslide}
        !           268: \ctitle        {APPLICATIONS}
        !           269: 
        !           270: \begin{nrtc}
        !           271: \item  APPLICATION CLASS
        !           272:     \begin{nrtc}
        !           273:     \item      A SET OF APPLICATIONS RELATED TO A PARTICULAR ACTIVITY,
        !           274:                e.g., FILE TRANSFER, IRREGARDLESS OF PROTOCOL SUITE
        !           275:     \end{nrtc}
        !           276: 
        !           277: \item  APPLICATION INSTANCE
        !           278:     \begin{nrtc}
        !           279:     \item      A MEMBER OF AN APPLICATION CLASS SPECIFIC TO A PARTICULAR
        !           280:                PROTOCOL SUITE, e.g., FTAM
        !           281:     \end{nrtc}
        !           282: \end{nrtc}
        !           283: \end{bwslide}
        !           284: 
        !           285: 
        !           286: \begin{bwslide}
        !           287: \part* {HISTORY}\bf
        !           288: 
        !           289: \begin{nrtc}
        !           290: \item  A VERY BRIEF INTRODUCTION TO THE TWO PROTOCOL SUITES
        !           291: 
        !           292: \item  WE'LL ATTEMPT TO TAKE A NON-PARTISAN VIEW (ha!)
        !           293: \end{nrtc}
        !           294: \end{bwslide}
        !           295: 
        !           296: 
        !           297: \begin{bwslide}
        !           298: \ctitle        {INTERNET SUITE}
        !           299: 
        !           300: \begin{nrtc}
        !           301: \item  SPONSORED BY THE U.S.~DoD
        !           302:     \begin{nrtc}
        !           303:     \item      GREW OUT OF EARLY (D)ARPA RESEARCH INTO SURVIVABLE NETWORKS
        !           304:     \end{nrtc}
        !           305:     BASIS FROM THE DoD INTERNET ARCHITECTURE MODEL
        !           306: 
        !           307: \item  SPECIFIED IN ``REQUEST FOR COMMENTS'' SERIES (RFCs) AND
        !           308:        U.S.~MILITARY STANDARDS (MILSTDs)
        !           309: 
        !           310: \item  CURRENT GENERATION PRIMARILY BASED ON
        !           311:     \begin{nrtc}
        !           312:     \item      CONNECTION-ORIENTED TRANSPORT SERVICE,
        !           313:                PROVIDED BY THE TCP; AND,
        !           314: 
        !           315:     \item      CONNECTIONLESS-MODE NETWORK SERVICE,
        !           316:                PROVIDED BY THE IP
        !           317:     \end{nrtc}
        !           318: 
        !           319: \item  MAJOR EMPHASIS ON CONNECTIVITY OF DIVERSE SUB-NETWORKS
        !           320:     \begin{nrtc}
        !           321:     \item      EXCELLENT RESEARCH CONTINUES, TO THIS DAY, ON THESE ISSUES
        !           322:     \end{nrtc}
        !           323: \end{nrtc}
        !           324: \end{bwslide}
        !           325: 
        !           326: 
        !           327: \begin{bwslide}
        !           328: \ctitle        {INTERNET SUITE (cont.)}
        !           329: 
        !           330: \begin{nrtc}
        !           331: \item  SEVERAL PRODUCTION APPLICATIONS
        !           332:     \begin{nrtc}
        !           333:     \item      SIMPLE MAIL TRANSFER PROTOCOL (SMTP)
        !           334: 
        !           335:     \item      FILE TRANSFER PROTOCOL (FTP)
        !           336: 
        !           337:     \item      TELNET (VIRTUAL TERMINAL PROTOCOL)
        !           338: 
        !           339:     \item      DOMAIN NAME SYSTEM (DNS)
        !           340:     \end{nrtc}
        !           341:     ALL OF WHICH ARE RATHER SIMPLE
        !           342: 
        !           343: \item  APPLICATIONS CONTAIN THEIR OWN IMPLICIT SESSION AND PRESENTATION
        !           344:        MECHANISMS
        !           345: 
        !           346: \item  NOT SURPRISING, CONSIDERING THAT THESE APPLICATIONS ARE ALL BASED ON
        !           347:        15~YEAR OLD MODELS!
        !           348: \end{nrtc}
        !           349: \end{bwslide}
        !           350: 
        !           351: 
        !           352: \begin{bwslide}
        !           353: \ctitle        {INTERNET PROTOCOLS}
        !           354: 
        !           355: \vskip.5in
        !           356: \diagram[p]{figureT-4}
        !           357: \end{bwslide}
        !           358: 
        !           359: 
        !           360: \begin{bwslide}
        !           361: \ctitle        {OSI SUITE}
        !           362: 
        !           363: \begin{nrtc}
        !           364: \item  SPONSORED BY THE INTERNATIONAL COMMUNITY
        !           365:     \begin{nrtc}
        !           366:     \item      IN PARTICULAR THE ISO
        !           367:     \end{nrtc}
        !           368:     BASIS FROM THE OSI REFERENCE MODEL (OSIRM)
        !           369: 
        !           370: \item  SPECIFIED IN ``STANDARDS'' (ISO/IEC)  AND RECOMMENDATIONS (CCITT)
        !           371: 
        !           372: \item  BASED ON
        !           373:     \begin{nrtc}
        !           374:     \item      CONNECTION-ORIENTED TRANSPORT SERVICE,
        !           375:                PROVIDED BY ONE OF FIVE DIFFERENT TPs; DEPENDING ON
        !           376: 
        !           377:     \item      THE NETWORK SERVICE AVAILABLE (CONS or CLNS)
        !           378:     \end{nrtc}
        !           379: 
        !           380: \item  DIFFICULT TO IDENTIFY THE ``MAJOR'' EMPHASIS
        !           381: \end{nrtc}
        !           382: \end{bwslide}
        !           383: 
        !           384: 
        !           385: \begin{bwslide}
        !           386: \ctitle        {OSI SUITE (cont.)}
        !           387: 
        !           388: \begin{nrtc}
        !           389: \item  SEVERAL INTERESTING APPLICATIONS
        !           390:     \begin{nrtc}
        !           391:     \item      MESSAGE HANDLING SYSTEMS (MHS)
        !           392: 
        !           393:     \item      FILE TRANSFER, ACCESS AND MANAGEMENT (FTAM)
        !           394: 
        !           395:     \item      VIRTUAL TERMINAL (VT)
        !           396: 
        !           397:     \item      DIRECTORY SERVICES (DS)
        !           398:     \end{nrtc}
        !           399: 
        !           400: \item  APPLICATIONS EVOLVING QUITE HEAVILY OVER THE LAST FEW YEARS
        !           401: 
        !           402: \item  MUCH MORE AMBITIOUS THAN THEIR INTERNET COUNTERPARTS
        !           403: \end{nrtc}
        !           404: \end{bwslide}
        !           405: 
        !           406: 
        !           407: \begin{bwslide}
        !           408: %%%\ctitle     {OSI PROTOCOLS}
        !           409: 
        !           410: %%%\vskip.25in
        !           411: \diagram[p]{figureT-5}
        !           412: \end{bwslide}
        !           413: 
        !           414: 
        !           415: \begin{bwslide}
        !           416: \ctitle        {A BRIEF COMPARISON}
        !           417: 
        !           418: \begin{nrtc}
        !           419: \item  NOTE THAT CONCERNS DIFFER
        !           420:     \begin{nrtc}
        !           421:     \item      NETWORK USERS: APPLICATION-LEVEL FUNCTIONALITY
        !           422: 
        !           423:     \item      NETWORK ADMINISTRATORS: NETWORK AND TRANSPORT ISSUES
        !           424:     \end{nrtc}
        !           425: 
        !           426: \item  FOR APPLICATIONS, ONCE IMPLEMENTED, THE OSI SUITE IS SUPERIOR
        !           427: 
        !           428: \item  FOR NETWORK/TRANSPORT ISSUES, AT PRESENT,
        !           429:        THE INTERNET SUITE IS SUPERIOR
        !           430: \end{nrtc}
        !           431: \end{bwslide}
        !           432: 
        !           433: 
        !           434: \begin{bwslide}
        !           435: \part* {METRICS FOR COMPARISON}\bf
        !           436: 
        !           437: \begin{nrtc}
        !           438: \item  CAN JUDGE A TRANSITION/COEXISTENCE SCHEME USING DIFFERENT
        !           439:        CRITERIA
        !           440: 
        !           441: \item  THE FOUR WE'LL FOCUS ON ARE ALL SUBJECTIVE;
        !           442:     \begin{nrtc}
        !           443:     \item      TECHNICAL SOLUTIONS DO NOT EXIST IN A VACUUM
        !           444: 
        !           445:     \item      THEY MUST BE EVALUATED IN THE CONTEXT OF A TARGET ENVIRONMENT
        !           446:     \end{nrtc}
        !           447: \end{nrtc}
        !           448: \end{bwslide}
        !           449: 
        !           450: 
        !           451: \begin{bwslide}
        !           452: \ctitle        {METRICS FOR COMPARISON (cont.)}
        !           453: 
        !           454: \begin{nrtc}
        !           455: \item  PERFORMANCE:
        !           456:     \begin{nrtc}
        !           457:     \item      THROUGHPUT, LATENCY
        !           458: 
        !           459:     \item      EFFECT ON OTHER APPLICATIONS
        !           460:     \end{nrtc}
        !           461: 
        !           462: \item  FLEXIBILITY:
        !           463:     \begin{nrtc}
        !           464:     \item      RANGE OF APPLICABILITY
        !           465:     \end{nrtc}
        !           466: \end{nrtc}
        !           467: \end{bwslide}
        !           468: 
        !           469: 
        !           470: \begin{bwslide}
        !           471: \ctitle        {METRICS FOR COMPARISON (cont.)}
        !           472: 
        !           473: \begin{nrtc}
        !           474: \item  TRANSPARENCY:
        !           475:     \begin{nrtc}
        !           476:     \item      USAGE CONTINUITY
        !           477: 
        !           478:     \item      SEAMLESS USER INTERFACE
        !           479:     \end{nrtc}
        !           480: 
        !           481: \item  AMENABILITY:
        !           482:     \begin{nrtc}
        !           483:     \item      MANAGEABILITY
        !           484:     \end{nrtc}
        !           485: \end{nrtc}
        !           486: \end{bwslide}
        !           487: 
        !           488: 
        !           489: \begin{bwslide}
        !           490: \ctitle        {SEVERAL CANDIDATES}
        !           491: 
        !           492: \begin{nrtc}
        !           493: \item  PROTOCOL-BASED APPROACHES
        !           494:     \begin{nrtc}
        !           495:     \item      DUAL STACK
        !           496: 
        !           497:     \item      APPLICATION GATEWAYS
        !           498: 
        !           499:     \item      TRANSPORT GATEWAYS
        !           500:     \end{nrtc}
        !           501: 
        !           502: \item  SERVICE-BASED APPROACHES
        !           503:     \begin{nrtc}
        !           504:     \item      TRANSPORT-SERVICE BRIDGES
        !           505: 
        !           506:     \item      NETWORK TUNNELS
        !           507:     \end{nrtc}
        !           508: 
        !           509: \item  NONE OF THESE TECHNIQUES ARE SPECIFIC TO THE PROBLEM OF
        !           510:     \begin{nrtc}
        !           511:     \item      INTERNET $\mapsto$ OSI
        !           512:     \end{nrtc}
        !           513: \end{nrtc}
        !           514: \end{bwslide}
        !           515: 
        !           516: 
        !           517: \begin{bwslide}
        !           518: \part  {PROTOCOL-BASED APPROACHES}\bf
        !           519: 
        !           520: \begin{nrtc}
        !           521: \item  THE ``STANDARD'' METHODS USED TO INTERCONNECT DIFFERENT
        !           522:        PROTOCOL STACKS
        !           523: 
        !           524: \item  THESE EMPHASIZE THE PROTOCOLS IN EACH STACK
        !           525: 
        !           526: \item  HENCE THEY REINFORCE THE BOUNDARIES BETWEEN TCP/IP AND OSI
        !           527: \end{nrtc}
        !           528: \end{bwslide}
        !           529: 
        !           530: 
        !           531: \begin{bwslide}
        !           532: \part* {DUAL STACK}\bf
        !           533: 
        !           534: \begin{nrtc}
        !           535: \item  PUT BOTH PROTOCOL SUITES IN ALL HOSTS
        !           536: 
        !           537: \item  WORKS WELL, IF YOU CAN CHANGE \underline{EVERYTHING} ON THE NETWORK
        !           538: \begin{quote}\em
        !           539: ``Nice work, if you can get it.''\\ \raggedleft
        !           540: -- Groucho Marx, Monkey Business, Paramount Pictures (1931)
        !           541: \end{quote}
        !           542: \end{nrtc}
        !           543: \end{bwslide}
        !           544: 
        !           545: 
        !           546: \begin{bwslide}
        !           547: \ctitle        {DUAL STACK (cont.)}
        !           548: 
        !           549: \vskip.5in
        !           550: \diagram[p]{figureT-1}
        !           551: \end{bwslide}
        !           552: 
        !           553: 
        !           554: \begin{bwslide}
        !           555: \ctitle        {TALKING TO UNI-STACK HOSTS}
        !           556: 
        !           557: \begin{nrtc}
        !           558: \item  QUESTION: HOW TO DECIDE WHICH APPLICATION INSTANCE,
        !           559:     \begin{nrtc}
        !           560:     \item      APPL-$\alpha$ OR APPL-$\gamma$,
        !           561:     \end{nrtc}
        !           562:        TO USE?
        !           563: 
        !           564: \item  TWO ANSWERS:
        !           565:     \begin{nrtc}
        !           566:     \item      DEPEND ON THE USER TO KNOW AND INVOKE THE RIGHT PROGRAM
        !           567: 
        !           568:     \item      DEVELOP A GENERIC APPLICATION WHICH SUPPORTS BOTH CLASSES
        !           569:     \end{nrtc}
        !           570: 
        !           571: \item  IN THE LATTER CASE, NEED AN UP-TO-DATE DIRECTORY TO DO THIS RELIABLY
        !           572: \end{nrtc}
        !           573: \end{bwslide}
        !           574: 
        !           575: 
        !           576: \begin{bwslide}
        !           577: \ctitle        {GENERIC APPLICATION INSTANCE}
        !           578: 
        !           579: \vskip.5in
        !           580: \diagram[p]{figureT-6}
        !           581: \end{bwslide}
        !           582: 
        !           583: 
        !           584: \begin{bwslide}
        !           585: \ctitle        {AN IMPLEMENTATION OF DUAL-STACK}
        !           586: 
        !           587: \begin{nrtc}
        !           588: \item  ENVIRONMENT: \unix/~SVR3 (STREAMS)
        !           589: 
        !           590: \item  ACCESS TO LOWER-LAYER PROTOCOLS VIA TRANSPORT LAYER INTERFACE (TLI)
        !           591: 
        !           592: \item  NOTE THAT ALTHOUGH TLI PROVIDES A UNIFORM INTERFACE,
        !           593:        IT DOES NOT PROVIDE A UNIFORM SERVICE:
        !           594:     \begin{nrtc}
        !           595:     \item      PACKET- vs. STREAM-ORIENTATION
        !           596: 
        !           597:     \item      GRACEFUL RELEASE
        !           598: 
        !           599:     \item      EXPEDITED vs. URGENT DATA
        !           600: 
        !           601:     \item      ADDRESSING
        !           602:     \end{nrtc}
        !           603: \end{nrtc}
        !           604: \end{bwslide}
        !           605: 
        !           606: 
        !           607: \begin{bwslide}
        !           608: \ctitle        {GENERIC APPLICATION INSTANCE}
        !           609: 
        !           610: \vskip.5in
        !           611: \diagram[p]{figureT-11}
        !           612: \end{bwslide}
        !           613: 
        !           614: 
        !           615: \begin{bwslide}
        !           616: \ctitle        {SCORECARD}
        !           617: 
        !           618: \begin{nrtc}
        !           619: \item  PERFORMANCE: NO DEGRADATION
        !           620: 
        !           621: \item  FLEXIBILITY: GOOD
        !           622: 
        !           623: \item  TRANSPARENCY:
        !           624:     \begin{nrtc}
        !           625:     \item      ASSUMING REMOTE SYSTEM SUPPORTS AT LEAST ONE OF THE PROTOCOL
        !           626:                STACKS, THEN HIGH TRANSPARENCY BY USING COMMON SERVICE
        !           627:                INTERFACE
        !           628:     \end{nrtc}
        !           629: 
        !           630: \item  AMENABILITY:
        !           631:     \begin{nrtc}
        !           632:     \item      BOTH END- AND INTERMEDIATE-SYSTEMS MUST RUN BOTH PROTOCOLS
        !           633: 
        !           634:     \item      INTRODUCES ADMINISTRATIVE PROBLEMS AS THERE ARE NOW TWO
        !           635:                LOGICAL NETWORKS
        !           636:        \begin{nrtc}
        !           637:        \item   MANAGEMENT OF BOTH \underline{PLUS} CONTENTION BETWEEN THEM
        !           638:        \end{nrtc}
        !           639:     \end{nrtc}
        !           640: \end{nrtc}
        !           641: \end{bwslide}
        !           642: 
        !           643: 
        !           644: \begin{bwslide}
        !           645: \part* {APPLICATION GATEWAYS}\bf
        !           646: 
        !           647: \begin{nrtc}
        !           648: \item  A WELL-KNOWN, BUT LITTLE-UNDERSTOOD TECHNOLOGY
        !           649:     \begin{nrtc}
        !           650:     \item      USED IN MESSAGE HANDLING QUITE A BIT
        !           651:     \end{nrtc}
        !           652: 
        !           653: \item  MOST ARE QUITE TERRIBLE
        !           654: \begin{quote}\em
        !           655: ``Sometimes when you try to turn an apple into an orange you get back a
        !           656: lemon.''\\ \raggedleft
        !           657: -- Michael Padlipsky, The Elements of Networking Style (1985)
        !           658: \end{quote}
        !           659: \end{nrtc}
        !           660: \end{bwslide}
        !           661: 
        !           662: 
        !           663: \begin{bwslide}
        !           664: \ctitle        {APPLICATION GATEWAYS (cont.)}
        !           665: 
        !           666: \vskip.5in
        !           667: \diagram[p]{figureT-2}
        !           668: \end{bwslide}
        !           669: 
        !           670: 
        !           671: \begin{bwslide}
        !           672: \ctitle        {IMPERFECT MAPPINGS}
        !           673: 
        !           674: \begin{nrtc}
        !           675: \item  BECAUSE THEY ARE AT THE HIGHEST LAYER IN THE STACK,
        !           676:        APPLICATION GATEWAYS TEND TO PERFORM SEMANTIC MAPPINGS
        !           677: 
        !           678: \item  THESE ARE ACCOMPANIED BY A LOSS OF INFORMATION
        !           679: 
        !           680: \item  SOMETIMES THE LOSS IS ONLY ANNOYING
        !           681:     \begin{nrtc}
        !           682:     \item      e.g., ``FUNNY LOOKING'' MAIL ADDRESSES
        !           683:     \end{nrtc}
        !           684: 
        !           685: \item  SOMETIMES THE LOSS IS CATASTROPHIC
        !           686:     \begin{nrtc}
        !           687:     \item      e.g., ROUTING LOOPS
        !           688:     \end{nrtc}
        !           689: \end{nrtc}
        !           690: \end{bwslide}
        !           691: 
        !           692: 
        !           693: \begin{bwslide}
        !           694: \ctitle        {AN IMPLEMENATION OF APPLICATION-GATEWAY}
        !           695: 
        !           696: \begin{nrtc}
        !           697: \item  TWO KINDS OF IMPLEMENATIONS
        !           698: 
        !           699: \item  STAGING (TRUE STORE-AND-FORWARD):
        !           700:     \begin{nrtc}
        !           701:     \item      TOP-LEVEL PROTOCOL TRANSACTIONS ARE GROUPED AT THE GATEWAY
        !           702: 
        !           703:     \item      REQUIRES LOCAL STORAGE, BUT MAY PERMIT BETTER MAPPINGS
        !           704:     \end{nrtc}
        !           705: 
        !           706: \item  IN-SITU (VIRTUAL END-TO-END):
        !           707:     \begin{nrtc}
        !           708:     \item      NO PROTOCOL TRANSACTIONS ARE GROUPED
        !           709: 
        !           710:     \item      MAPPINGS ARE ``ON THE FLY''\\ (AND PERHAPS LESS PRECISE)
        !           711: 
        !           712:     \item      END-TO-END RESPONSE IS FASTER
        !           713:     \end{nrtc}
        !           714: \end{nrtc}
        !           715: \end{bwslide}
        !           716: 
        !           717: 
        !           718: \begin{bwslide}
        !           719: \ctitle        {INVOKING THE GATEWAY}
        !           720: 
        !           721: \vskip1.5in
        !           722: \begin{verbatim}
        !           723: % ftp file-gateway
        !           724: Name (file-gateway:asterix): obelix@osi-host
        !           725: Password:
        !           726: \end{verbatim}
        !           727: \end{bwslide}
        !           728: 
        !           729: 
        !           730: \begin{bwslide}
        !           731: \ctitle        {A STAGING IMPLEMENTATION}
        !           732: 
        !           733: \vskip.5in
        !           734: \diagram[p]{figureT-12}
        !           735: \end{bwslide}
        !           736: 
        !           737: 
        !           738: \begin{bwslide}
        !           739: \ctitle        {AN IN-SITU IMPLEMENTATION}
        !           740: 
        !           741: \vskip.5in
        !           742: \diagram[p]{figureT-13}
        !           743: \end{bwslide}
        !           744: 
        !           745: 
        !           746: \begin{bwslide}
        !           747: \ctitle        {SCORECARD}
        !           748: 
        !           749: \begin{nrtc}
        !           750: \item  PERFORMANCE: USUALLY POOR, BUT ACCEPTABLE FOR STORE-AND-FORWARD
        !           751:        APPLICATIONS
        !           752:     \begin{nrtc}
        !           753:     \item      TYPICALLY ALSO INTRODUCES ADDITIONAL NETWORK TRAFFIC
        !           754:     \end{nrtc}
        !           755: 
        !           756: \item  FLEXIBILITY: NONE; EACH A-GWY IS A SPECIAL-PURPOSE SOFTWARE BOX
        !           757: 
        !           758: \item  TRANSPARENCY: 
        !           759:     \begin{nrtc}
        !           760:     \item      TO SERVICE: OFTEN LOSES SIGNIFICANT FUNCTIONALITY
        !           761: 
        !           762:     \item      TO USERS: POSSIBLE, BUT NOT LIKELY (e.g., IN AN FTAM/FTP A-GWY,
        !           763:                USERS EMBED HOSTNAMES IN FILENAMES)
        !           764:     \end{nrtc}
        !           765: 
        !           766: \item  AMENABILITY:
        !           767:     \begin{nrtc}
        !           768:     \item      REQUIRES NO END-SYSTEM MODIFICATION
        !           769: 
        !           770:     \item      MAY INTRODUCE ADMINISTRATIVE PROBLEMS
        !           771:     \end{nrtc}
        !           772: \end{nrtc}
        !           773: \end{bwslide}
        !           774: 
        !           775: 
        !           776: \begin{bwslide}
        !           777: \part* {TRANSPORT GATEWAYS}\bf
        !           778: 
        !           779: \begin{nrtc}
        !           780: \item  IDEA: GATEWAY AT THE TRANSPORT LAYER SO AS TO AVOID NEEDING
        !           781:        MULTIPLE APPLICATION GATEWAYS
        !           782: \begin{quote}\em
        !           783: ``We could do it, but it would be wrong.''\\ \raggedleft
        !           784: -- Richard Nixon, The Watergate Tapes (1974)
        !           785: \end{quote}
        !           786: 
        !           787: \item  ALTHOUGH THE OSI (TP4) AND INTERNET (TCP) TRANSPORT PROTOCOLS DIFFER,
        !           788:        THE SERVICE IS QUITE SIMILAR
        !           789: 
        !           790: \item  HENCE, IT IS TECHNICALLY FEASIBLE TO PERFORM THE MAPPINGS
        !           791:     \begin{nrtc}
        !           792:     \item      (ALTHOUGH IT'S A LOT OF HARD WORK)
        !           793:     \end{nrtc}
        !           794: \end{nrtc}
        !           795: \end{bwslide}
        !           796: 
        !           797: 
        !           798: \begin{bwslide}
        !           799: \ctitle        {TRANSPORT GATEWAYS (cont.)}
        !           800: 
        !           801: \vskip.5in
        !           802: \diagram[p]{figureT-14}
        !           803: \end{bwslide}
        !           804: 
        !           805: 
        !           806: \begin{bwslide}
        !           807: \ctitle        {THE OBVIOUS QUESTION}
        !           808: 
        !           809: \begin{nrtc}
        !           810: \item  WHAT APPLICATION DO YOU RUN WHEN USING THIS?
        !           811:     \begin{nrtc}
        !           812:     \item      CAN'T RUN INTERNET APPLICATIONS IN THE OSI NETWORK,
        !           813:                SINCE THE TRANSPORT GATEWAY YIELDS OSI TRANSPORT SEMANTICS
        !           814: 
        !           815:     \item      CAN'T RUN OSI APPLICATIONS IN THE INTERNET NETWORK,
        !           816:                SINCE THE TRANSPORT GATEWAY YIELDS INTERNET TRANSPORT SEMANTICS
        !           817:     \end{nrtc}
        !           818: 
        !           819: \item  THIS APPROACH FAILS BECAUSE IT PRESENTS DIFFERENT SERVICE SEMANTICS
        !           820:        IN EACH NETWORK
        !           821: \end{nrtc}
        !           822: \end{bwslide}
        !           823: 
        !           824: 
        !           825: \begin{bwslide}
        !           826: \part  {SERVICE-BASED APPROACHES}\bf
        !           827: 
        !           828: \begin{nrtc}
        !           829: \item  BY THE TIME OSI-BASED NETWORKS ARE TRULY WIDESPREAD,
        !           830:        TCP/IP-BASED NETWORKS WILL ALREADY OFFER A MIX OF SERVICES:
        !           831:     \begin{nrtc}
        !           832:     \item      SUCH AS FTAM AND MHS, IN ADDITION TO FTP AND SMTP
        !           833:     \end{nrtc}
        !           834: 
        !           835: \item  IN OTHER WORDS, PERHAPS THE TRANSITION TO OSI BEGINS WITH NEW
        !           836:        APPLICATIONS ON HOSTS AND NO CHANGES TO THE NETWORK
        !           837: \end{nrtc}
        !           838: \end{bwslide}
        !           839: 
        !           840: 
        !           841: \begin{bwslide}
        !           842: \ctitle        {WOULD THIS REALLY HAPPEN?}
        !           843: 
        !           844: \begin{nrtc}
        !           845: \item  RECALL THAT USERS ARE INTERESTED IN \underline{SERVICES} NOT
        !           846:        \underline{PROTOCOLS}
        !           847: 
        !           848: \item  THE OSI APPLICATIONS ARE MUCH RICHER THAN THEIR INTERNET COUNTERPARTS
        !           849: 
        !           850: \item  IN CONTRAST, AT THE LOWER-LAYERS THE INTERNET SUITE ``WORKS BETTER''
        !           851:     \begin{nrtc}
        !           852:     \item      AS SUCH, IT IS UNLIKELY TO BE REPLACED BY THE OSI LOWER-LAYERS
        !           853:                FOR QUITE SOME TIME
        !           854:     \end{nrtc}
        !           855: \end{nrtc}
        !           856: \end{bwslide}
        !           857: 
        !           858: 
        !           859: \begin{bwslide}
        !           860: \ctitle        {OBSERVATION}
        !           861: 
        !           862: \begin{nrtc}
        !           863: \item  GIVEN THE ABOVE ASSUMPTION, IT SHOULD BE NOTED THAT:
        !           864:     \begin{nrtc}
        !           865:     \item      WE HAVE TWO COMMUNITIES USING THE SAME APPLICATIONS
        !           866:                (OSI), AND
        !           867: 
        !           868:     \item      ONLY THE UNDERLYING ``TS-STACK'' WILL DIFFER BETWEEN THE TWO:
        !           869:        \begin{nrtc}
        !           870:        \item   IN THE OSI COMMUNITY: TP4/CLNP/$\ldots$
        !           871: 
        !           872:        \item   IN THE TCP COMMUNITY: RFC1006/TCP/IP/$\ldots$
        !           873:        \end{nrtc}
        !           874:     \end{nrtc}
        !           875: 
        !           876: \item  THIS LEADS US TO POSTULATE AN INTERESTING COEXISTENCE
        !           877:        STRATEGY:
        !           878:     \begin{nrtc}
        !           879:     \item      LET'S RUN OSI APPLICATIONS, END-TO-END, BETWEEN THE TWO
        !           880:     \end{nrtc}
        !           881: 
        !           882: \item  IN A SENSE, THIS IS A HYBRID OF THE TWO PREVIOUS APPROACHES,
        !           883:        INTENDED TO MINIMIZE THE DISADVANTAGES OF EACH
        !           884:     \begin{nrtc}
        !           885:        \item   SAME APPLICATION PROTOCOL,\\
        !           886:                BUT DIFFERENT UNDERYLING LAYERS
        !           887:     \end{nrtc}
        !           888: \end{nrtc}
        !           889: \end{bwslide}
        !           890: 
        !           891: 
        !           892: \begin{bwslide}
        !           893: \part* {TRANSPORT-SERVICE BRIDGES}\bf
        !           894: 
        !           895: \begin{nrtc}
        !           896: \item  INTRODUCE A TRANSPORT ENTITY CALLED THE ``TS-BRIDGE''
        !           897: \begin{quote}\em
        !           898: ``Users are interested in services, not protocols.''\\ \raggedleft
        !           899: -- Marshall Rose, The Open Book (1990)
        !           900: \end{quote}
        !           901: 
        !           902: \item  THE TS-BRIDGE ``COPIES'' SERVICE PRIMITIVES FROM ONE TS-STACK TO THE
        !           903:        OTHER, e.g.:
        !           904:     \begin{nrtc}
        !           905:     \item      UPON RECEIVING A T-CONNECT.INDICATION PRIMITIVE FROM ONE
        !           906:                TS-STACK,
        !           907: 
        !           908:     \item      IT ISSUES A T-CONNECT.REQUEST PRIMITIVE TO THE OTHER TS-STACK
        !           909:     \end{nrtc}
        !           910: 
        !           911: \item  AS DISCUSSED EARLIER, THIS TECHNOLOGY IS USED FOR CONNECTIVITY BETWEEN
        !           912:        DIFFERENT OSI COMMUNITIES
        !           913: \end{nrtc}
        !           914: \end{bwslide}
        !           915: 
        !           916: 
        !           917: \begin{bwslide}
        !           918: \ctitle        {TRANSPORT-SERVICE BRIDGES (cont.)}
        !           919: 
        !           920: \vskip.5in
        !           921: \diagram[p]{figureT-9}
        !           922: \end{bwslide}
        !           923: 
        !           924: 
        !           925: \begin{bwslide}
        !           926: \ctitle        {CONS vs. CLNS CONNECTIVITY}
        !           927: 
        !           928: \vskip.5in
        !           929: \diagram[p]{figureT-19}
        !           930: \end{bwslide}
        !           931: 
        !           932: 
        !           933: \begin{bwslide}
        !           934: \ctitle        {THE TS-BRIDGE AND THE OSI MODEL\\ (REVIEW)}
        !           935: 
        !           936: \begin{nrtc}
        !           937: \item  THE TS-BRIDGE IS A LEVEL-FOUR ROUTER
        !           938: 
        !           939: \item  POTENTIAL PROBLEMS:
        !           940:     \begin{nrtc}
        !           941:     \item      THE TS-BRIDGE MAINTAINS STATE AS TO THE EXISTING CONNECTIONS
        !           942: 
        !           943:     \item      TWO CHECKSUMS, AND NEITHER REALLY END-TO-END
        !           944: 
        !           945:     \item      \underline{MAY} THWART SOPHISTICATED BACK-PRESSURE TECHNIQUES
        !           946:     \end{nrtc}
        !           947: \end{nrtc}
        !           948: \end{bwslide}
        !           949: 
        !           950: 
        !           951: \begin{bwslide}
        !           952: \ctitle        {AN IMPLEMENTATION OF THE TS-BRIDGE}
        !           953: 
        !           954: \begin{nrtc}
        !           955: \item  FIRST DEMONSTRATION IN FEBRUARY, 1988
        !           956:     \begin{nrtc}
        !           957:     \item      TP4/CLNP to RFC1006/TCP
        !           958:     \end{nrtc}
        !           959: 
        !           960: \item  ANOTHER IMPLEMENTATION IN EUROPE IS HANDLING
        !           961:     \begin{nrtc}
        !           962:     \item      TP0/X.25 to RFC1006/TCP
        !           963:     \end{nrtc}
        !           964: \end{nrtc}
        !           965: \end{bwslide}
        !           966: 
        !           967: 
        !           968: \begin{bwslide}
        !           969: \ctitle        {SCORECARD}
        !           970: 
        !           971: \begin{nrtc}
        !           972: \item  PERFORMANCE: FAIR
        !           973: 
        !           974: \item  FLEXIBILITY: HIGH; INDEPENDENT OF ANY APPLICATION
        !           975: 
        !           976: \item  TRANSPARENCY: TOTAL
        !           977: 
        !           978: \item  AMENABILITY:
        !           979:     \begin{nrtc}
        !           980:     \item      TCP END-SYSTEMS MUST RUN ``NEW'' PROTOCOLS
        !           981:        \begin{nrtc}
        !           982:        \item   BUT, NO MODIFICATIONS REQUIRED TO END-SYSTEM KERNELS
        !           983:        \end{nrtc}
        !           984: 
        !           985:     \item      MAY INTRODUCE ADMINISTRATIVE PROBLEMS
        !           986:     \end{nrtc}
        !           987: \end{nrtc}
        !           988: \end{bwslide}
        !           989: 
        !           990: 
        !           991: \begin{bwslide}
        !           992: \part* {NETWORK TUNNELS}\bf
        !           993: 
        !           994: \begin{nrtc}
        !           995: \item  IDEA: ENCAPSULATE CLNP INSIDE OF IP, TREATING IP AS SIMPLY A DATA LINK
        !           996:        PROTOCOL
        !           997: \begin{quote}\em
        !           998: ``Encapsulation complies with the layering concept, but violates the notion
        !           999: of absolute levels.''\\ \raggedleft
        !          1000: -- Danny Cohen and Jon Postel, ``The ISO Reference Model and Other Protocol
        !          1001: Architectures'' (1983)
        !          1002: \end{quote}
        !          1003: 
        !          1004: \item  NS-TUNNEL PERFORMS AS A ROUTER, REMOVING ONE DATA LINK HEADER AND
        !          1005:        ADDING ANOTHER
        !          1006: 
        !          1007: \item  METHOD SPECIFIED IN [RFC1070]
        !          1008: 
        !          1009: \item  ADDRESS MAPPINGS SPECIFIED IN [RFC1069] 
        !          1010: \end{nrtc}
        !          1011: \end{bwslide}
        !          1012: 
        !          1013: 
        !          1014: \begin{bwslide}
        !          1015: \ctitle        {TUNNELING}
        !          1016: 
        !          1017: \vskip.5in
        !          1018: \diagram[p]{figureT-18}
        !          1019: \end{bwslide}
        !          1020: 
        !          1021: 
        !          1022: \begin{bwslide}
        !          1023: \ctitle        {NETWORK TUNNELS}
        !          1024: 
        !          1025: \vskip.5in
        !          1026: \diagram[p]{figureT-10}
        !          1027: \end{bwslide}
        !          1028: 
        !          1029: 
        !          1030: \begin{bwslide}
        !          1031: \ctitle        {INTERESTING FEATURES}
        !          1032: 
        !          1033: \begin{nrtc}
        !          1034: \item  NO STATE MAINTAINED BY NS-TUNNEL
        !          1035: 
        !          1036: \item  A TRUE END-TO-END CHECKSUM
        !          1037: \end{nrtc}
        !          1038: \end{bwslide}
        !          1039: 
        !          1040: 
        !          1041: \begin{bwslide}
        !          1042: \ctitle        {POTENTIAL PROBLEMS}
        !          1043: 
        !          1044: \begin{nrtc}
        !          1045: \item  REQUIRES COMMON HIGHER-LEVEL PROTOCOLS (TRANSPORT AND ABOVE) ON BOTH
        !          1046:        END-SYSTEMS, BUT DOES NOT REQUIRE ALL INTERVENING ROUTERS TO USE THE
        !          1047:        SAME NETWORK PROTOCOL
        !          1048: 
        !          1049: \item  THE TCP END-SYSTEM IMPLEMENTATION CHOICES ARE SIMILAR TO NETBIOS OVER
        !          1050:        TCP [RFC1001/1002]
        !          1051: \end{nrtc}
        !          1052: \end{bwslide}
        !          1053: 
        !          1054: 
        !          1055: \begin{bwslide}
        !          1056: \ctitle        {AN IMPLEMENATION OF AN NS-TUNNEL}
        !          1057: 
        !          1058: \begin{nrtc}
        !          1059: \item  HAVEN'T SEE ANY YET
        !          1060:     \begin{nrtc}
        !          1061:     \item      BUT WILL BE IN 4.4BSD UNIX
        !          1062:     \end{nrtc}
        !          1063: 
        !          1064: \item  NEED A LOT OF CLNP-BASED NETWORKS BEFORE THIS IS OF USE
        !          1065: 
        !          1066: \item  SO THIS WILL HAPPEN AT THE END OF THE TRANSITION PERIOD
        !          1067: \end{nrtc}
        !          1068: \end{bwslide}
        !          1069: 
        !          1070: 
        !          1071: \begin{bwslide}
        !          1072: \ctitle        {SCORECARD}
        !          1073: 
        !          1074: \begin{nrtc}
        !          1075: \item  PERFORMANCE: NO WORSE THAN TYPICAL CLNP-ROUTER (AND PROBABLY A LOT
        !          1076:        BETTER TOO!)
        !          1077: 
        !          1078: \item  FLEXIBILITY: HIGH (INDEPENDENT OF ANY APPLICATION)
        !          1079: 
        !          1080: \item  TRANSPARENCY: TOTAL
        !          1081: 
        !          1082: \item  AMENABILITY: TCP END-SYSTEMS MUST RUN BOTH TRANSPORT PROTOCOLS
        !          1083: \end{nrtc}
        !          1084: \end{bwslide}
        !          1085: 
        !          1086: 
        !          1087: \begin{bwslide}
        !          1088: \part  {EXAMPLES}\bf
        !          1089: 
        !          1090: \begin{nrtc}
        !          1091: \item  DoD OSI IMPLEMENTATION PLAN
        !          1092: 
        !          1093: \item  GENERIC EXAMPLE
        !          1094: 
        !          1095: \item  CONCLUSIONS
        !          1096: \end{nrtc}
        !          1097: \end{bwslide}
        !          1098: 
        !          1099: 
        !          1100: \begin{bwslide}
        !          1101: \part* {DoD OSI\\ IMPLEMENTATION PLAN}\bf
        !          1102: 
        !          1103: \begin{nrtc}
        !          1104: \item  IMPLEMENT CAPABILITY TO USE OSI IN DoD INTERNETWORK ENVIRONMENT
        !          1105:     \begin{nrtc}
        !          1106:     \item      OSI-POSIX PROJECT
        !          1107:     \end{nrtc}
        !          1108: 
        !          1109: \item  PROVIDE THE CAPABILITY FOR DoD AND OSI PROTOCOLS TO INTEROPERATE
        !          1110:     \begin{nrtc}
        !          1111:     \item      FTAM-FTP GATEWAY
        !          1112: 
        !          1113:     \item      MHS-SMTP GATEWAY
        !          1114:     \end{nrtc}
        !          1115: \end{nrtc}
        !          1116: \end{bwslide}
        !          1117: 
        !          1118: 
        !          1119: \begin{bwslide}
        !          1120: \ctitle        {OSI-POSIX PROJECT}
        !          1121: 
        !          1122: \begin{nrtc}
        !          1123: \item  GOAL: ACCELLERATE THE UBIQUITY OF OSI
        !          1124: 
        !          1125: \item  APPROACH: OPENLY AVAILABLE, COMPLETE OSI IMPLEMENTATION FOR NEXT MAJOR
        !          1126:        RELEASE OF BERKELEY \unix/
        !          1127: 
        !          1128: \item  FOR MORE DETAILS:
        !          1129: \begin{quote}
        !          1130: OSI PROTOCOLS WITHIN AN OPENLY AVAILABLE, POSIX-CONFORMANT, BERKELEY UNIX
        !          1131: ENVIRONMENT
        !          1132: \end{quote}
        !          1133: APPEARING IN ConneXions, OCTOBER, 1988
        !          1134: \end{nrtc}
        !          1135: \end{bwslide}
        !          1136: 
        !          1137: 
        !          1138: \begin{bwslide}
        !          1139: \diagram[p]{figureT-15}
        !          1140: \end{bwslide}
        !          1141: 
        !          1142: 
        !          1143: \begin{bwslide}
        !          1144: \diagram[p]{figureT-16}
        !          1145: \end{bwslide}
        !          1146: 
        !          1147: 
        !          1148: \begin{bwslide}
        !          1149: \part* {GENERIC EXAMPLE}\bf
        !          1150: 
        !          1151: \begin{nrtc}
        !          1152: \item  TWO PRONGS:
        !          1153:     \begin{nrtc}
        !          1154:     \item      FAVOR USE OF OSI APPLICATIONS OVER TCP ON LAN MESH
        !          1155: 
        !          1156:     \item      LOCATE APPLICATION GATEWAYS AND A TS-BRIDGE ON ALL NODES
        !          1157:                WITH WAN ATTACHMENETS
        !          1158:     \end{nrtc}
        !          1159: 
        !          1160: \item  AWAIT OSI LOWER-LAYERS TO BECOME COMPETITIVE
        !          1161: \end{nrtc}
        !          1162: \end{bwslide}
        !          1163: 
        !          1164: 
        !          1165: \begin{bwslide}
        !          1166: \ctitle        {GENERIC EXAMPLE (cont.)}
        !          1167: 
        !          1168: \begin{nrtc}
        !          1169: \item  EACH ATTACHMENT LOCUS SHOULD SUPPORT COEXISTENCE SERVICES
        !          1170: 
        !          1171: \item  IF RESOURCES PERMIT, SELECT ONE OTHER SYSTEM TO SUPPORT THESE
        !          1172:        SERVICES FOR USE BY LOCAL UNI-STACK HOSTS
        !          1173: 
        !          1174: \item  THIS ``COVERS ALL BASES'' BY HANDLING ALL POSSIBLE OSI COMBINATIONS
        !          1175:        WITH A BIT OF EXTRA REDUNDANCY
        !          1176: 
        !          1177: \item  MIGHT REQUIRE A BIT OF SOPHISTICATED USE FROM THE DIRECTORY
        !          1178: \end{nrtc}
        !          1179: \end{bwslide}
        !          1180: 
        !          1181: 
        !          1182: \begin{bwslide}
        !          1183: \ctitle        {A LAN OF MANY COLORS}
        !          1184: 
        !          1185: \vskip.5in
        !          1186: \diagram[p]{figureT-17}
        !          1187: \end{bwslide}
        !          1188: 
        !          1189: 
        !          1190: \begin{bwslide}
        !          1191: \part* {CONCLUSIONS}\bf
        !          1192: 
        !          1193: \begin{quote}\em
        !          1194: ``Optimality differs according to context.''\\ \raggedleft
        !          1195: -- Michael Padlipsky, The Elements of Networking Style (1985)
        !          1196: \end{quote}
        !          1197: \end{bwslide}
        !          1198: 
        !          1199: 
        !          1200: \begin{bwslide}
        !          1201: \ctitle        {CONCLUSIONS (cont.)}
        !          1202: 
        !          1203: \begin{nrtc}
        !          1204: \item  TCP/IP-BASED NETWORKS WILL OFFER OSI APPLICATIONS
        !          1205: 
        !          1206: \item  COEXISTENCE IN THE SHORT TERM:
        !          1207:     \begin{nrtc}
        !          1208:     \item      TS-BRIDGE MINIMIZES SOFTWARE INVESTMENT
        !          1209:     \end{nrtc}
        !          1210: 
        !          1211: \item  COEXISTENCE IN THE LONG TERM:
        !          1212:     \begin{nrtc}
        !          1213:     \item      NS-TUNNEL MAXIMIZES PERFORMANCE AND ROBUSTNESS
        !          1214:     \end{nrtc}
        !          1215: 
        !          1216: \item  IF/WHEN THERE ARE NO MORE TCP/IP-BASED NETWORKS, THEN THE
        !          1217:        COEXISTENCE PERIOD IS OVER, AND TRANSITION IS A NON-ISSUE!
        !          1218: \end{nrtc}
        !          1219: \end{bwslide}

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