DTJ Number 3 September 1987 - Digital Technical Journals

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New Productssoles for management or system-level debugging.Moreover, reverse LAT can also be usedto provide shared access to a pool of dial-outmodems.fImplementations and Applications0
Terminal Servers on Ethernet Local Area NetworksFigure 4Communications ServerInternally, the DECserver 100 is radically differentfrom the other two members of theterminal server family, yet still retains the sameexternal characteristics. The DECserver 100 is alow-cost terminal server capable of connectingeight asynchronous ASCII terminals to an Ethernetusing the LAT protocol. This server is a verycompact unit and can be located in a computerroom, a communications closet, or in an officeenvironment. The server has no modem control.Modem control is implemented using an 8-MHzMotorola 68000 chip, with 128KB of RAM , and512 bytes of nonvolatile RAM (NVRAM). Like theEthernet Terminal Server software, the DECserver100 software is down-line loaded from aDECnet load host.Inc. Each PAM interface connects up to eight linecards, each of which is a dual RS232C interfacewith full modem-control capability. The serveralso has a console boot terminator (CBT) modulefor self-test code, bootstrap code, and remoteconsole support. The Ethernet Terminal Serveroffers a user interface similar to that on the DECserver100. Using the LAT protocol, the servercan connect up to 32 terminals (either locally orremotely via modems) to the Ethernet. The EthernetTerminal Server can be located in a computerroom environment or a communicationscloset. The software is always down-line loadedinto the unit from a DECnet load host across theEthernet.Extensions to the OriginalImplementationsThe initial implementations of the LAT protocolwere on the terminal servers described aboveand on VAX/VMS host systems. The serversimplemented only the master end of theLAT protocol, whereas the hosts implementedthe slave end . Follow-on implementationshave added similar support for additionalhost systems: the MicroVMS, RSX- 11M-PLUS,MicroRSX, ULTRIX-32, ULTRIX-32m, TOPS- 10,and TOPS-20 systems.Each system implementation offers access tothe command interpreter as the service accesspoint. Figure 5 illustrates this support.VAX/VMSSYSTEMRSX1 1 -M-PLUSSYSTEMUL TRIX-32SYSTEMTOPS-20SYSTEMMicroVMS MicroRSX TOPS-10SYSTEMSYSTEMSYSTEMIIIIIETHERNETDECserver 100TERMINAL// .\\. .TERMINALSSERVERIITERMINALS\\DIAL-INMODEMSFigure 5Additional LA T Host Support84 <strong>Digital</strong> TecbnicaljournalNo. 3 <strong>September</strong> 1986
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Netwo;king ProductsDigital Technica
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Editor's IntroductionRichard W. Bea
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BiographiesRaj Jain Raj Jain gradua
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BiographiesDavid R. Oran Dave Oran
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increase the sizes of networks, we
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New Productsmust be able to coexist
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A Digital Network Architecture Over
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---A Digital Network Architecture O
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Performance Analysis and Modeling o
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---Performance Analysis and Modelin
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Performance Analysis and Modeling o
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Page 35 and 36: --Performance Analysis and Modeling
Page 37 and 38: The DECnet/SNA Gateway Product• H
Page 39 and 40: The DECnetjSNA Gateway ProductFrom
Page 41 and 42: The DECnetjSNA Gateway Productcommu
Page 43 and 44: The DECnetjSNA Gateway ProductUSER
Page 45 and 46: The DECnetjSNA Gateway ProductThe u
Page 47 and 48: The DECnetjSNA Gateway ProductDECne
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Page 51 and 52: The DECnetjSNA Gateway ProductSegme
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Page 55 and 56: WiUiam R. HaweMark F. KempfAlanJ. K
Page 57 and 58: The Extended Local Area Network Arc
Page 75 and 76: Terminal Servers on Ethernet Local
Page 83: Terminal Servers on Ethernet Local
Page 89 and 90: Paul R. Beckjames A. KryckaThe DECn
Page 91 and 92: The DEC net- VA X Product - An Inte
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Page 95 and 96: The DECnet- VAX Product - An Integr
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Page 101 and 102: john Forecastjames L. jacksonjeffre
Page 103 and 104: The DECnet,ULTRIX SoftwareComponent
Page 105 and 106: The DECnet- ULTRIX Softwarehave pro
Page 107 and 108: The DECnet- ULTRIX Softwaresystems.
Page 109 and 110: Peter 0. MierswaIDavid J. MittonMar
Page 111 and 112: The DECnet-DOS Systemthat CCB, whic
Page 113 and 114: The DECnet-DOS Systemdata link laye
Page 115 and 116: Tbe DECnet-DOS SystemNDU and the vi
Page 117 and 118: Th e DECnet-DOS Systemconsole can a
Page 119 and 120: The Evolution of Network Management
Page 131 and 132: The NMCCjDECnet Monitor Design5. Op
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The NMCCjDECnet Monitor DesignKERNE
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The NMCCjDECnet Monitor Designinto
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The NMCCj/JECnet Monitor DesignThe
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The NMCCjDECnet Monitor Designcan s
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Editorial StaffEditor - Richard W.
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