DTJ Number 3 September 1987 - Digital Technical Journals

More documents

Recommendations

Info

New Productsrec overy of received signals, and interfacingthe communications channel to any processorand memory used to implement higher-levelprotocol functions. Implementations of thislayer encompass hardware interface devicesand device drivers in operating systems, aswell as communic ations hardware suc h asmodems, transceivers, and the physical channelsthemselves.Protocols for the physical layer are rudimentary,emphasizing the specification of electricalinterfacing parameters. No special physical layerspecifications have been developed for DNA.Instead, it relies on industry standards for thephysical layer, thereby ensuring that DECnetproducts can operate over available communicationstechnologies and infrastructures. Physicallayer standards supported by DNA for wide areanetworks include the EIA RS-232C and RS-423specifications, and the CCITT V.24 and X.25Level 1 specific ations. Physical layer standardssupported by the DNA architecture forLANs include two baseband implementationsof ThinWire Ethernet, the original18 and thethinwire2 3 specifications, and a broadband24implementation.Future Directions fo r the DNAArchitectureFor ten years, DNA has evolved in four maindimensions: network applications, communicationstechnologies, network size and scale, anddiversity of supported computer systems. Thisability to evolve independentl y along fourdimensions has proven to be one of the principalbenefits of the architecture. It is reasonable toassume that evolution along these lines will continue.Local area and wide area communicationstechnologies continue to evolve, typically resul ting in higher communications data rates. Newapplications for computer networks and newapplications protocols will also continue toevolve. The DNA architecture will continue toaccommodate these trends.The 16-bit node addresses used by DNA PhaseIV currently limit the size of DECnet networks. ·Digital's own internal DECnet network is nearingthe limits of this address space; over 10, 000nodes are currently registered. Clearly, the architecturemust be extended to support morenodes. From our experience with this network,there are two separate reasons why networkscontinue to grow rapidly. First, the availability oflow-cost computer systems allows individuals toown network nodes rather than sharing a singletimesharing system. Second, certain applications,such as network mail, need to operateacross whole organizations. This breadth makes asingle company-wide network, rather than separateindependent networks, highly desirable.Indeed, there is even a need for networks thatspan multiple organizations, adding further tothe problems of sc ale, complicating networkmanagement requirements, and creating newproblems of network security. DNA will have toevolve to adapt to much larger and more diversenetworks.As computer networks have beco me larger,users have developed increasing requirementsfor networks that interconnect computer systemsfrom multiple vendors. The International StandardsOrganization (ISO) has been developingstandards for such networks through their OpenSystems Interconnection program (OSI) . The OSlreference model defines a network architecturesimilar in many respec ts to that of DNA. 25 Mostmajor computer vendors, ncluding Digital, haveannounced their support tor OSI and are beginningto deliver OSI network products. Digital hasannounced its strategy to incorporate OSI protocolsinto its networking products, integratingthem into the DNA arc hitecture. Future versionsof the DNA arc hitec ture will correspondto a mixture of standardized and proprietaryprotocols.References1. DECnet Digital Ne twork Architecture(Phase IV) General Description (Bedford:Digital Equipment Corporation,Order No. AA-149A-TC, 1982) .2. DECnet Digital Network Architecture(Phase IV) Network Management FunctionalSp ecification (Bedford: DigitalEquipment Corporation, Order No.AA-X437A-TK, 1983).3. DECnet Digital Network Architecture(Phase IV) Maintenance Op erationsFu nctional Specification (Bedford: DigitalEquipment Corporation, Order No.AA-X436A-TK, 1983).4. N. La Pelle, M. Seger, and M. Sylor, "TheEvolution of Network Management Products," Digital Technical journal (September1986, this issue): 117-128.Digital TecbnicalJournalNo. 3 September 198623
A Digital Network Architecture Overview5. DECnet Digital Network ArchitectureData Access Protocol (DAP) FunctionalSpecification (Bedford: Digital EquipmentCorporation, Order No. AA-K177A-TK,1983).6. J. Morency, D. Porter, R. Pitkin, and D.Oran , ''The DECnetjSNA GatewayProduct - A Case Study in Cross VendorNetworking,'' Digital Technical jo urnal(September 1986, this issue) : 35-53.7. P. Beck and J. Krycka, "The DECnet-VAXProduct -An Integrated Approach to Networking,"Digital Technical journal (September1986, this issue) : 88-99.8. DEC net Digital Network Architecture SessionControl Layer Functional Specification(Bedford: Digital Equipment Corporation,Order No. AA-K 182A-TK, 1980) .9. DECnet Digital Network Architecture(Phase IV) NSP Functional Specification(Bedford: Digital Equipment Corporation,Order No. AA-X439A-TK, 1983) .10. C. Sunshine and Y. Dalal, "ConnectionManagement in Transport Protocols,"Computer Networks , vol . 2 (December1978): 454-473.11. W. Lai, "Protocol Traps in Computer Networks-A Catalog,'' IEEE Tra nsactionson Communication , vol . COM-30, no. 6oune 1982): 1434-1449.12. DECnet Digital Network Architecture(Phase IV) Routing Layer FunctionalSpecification (Bedford: Digital EquipmentCorporation, Order No. AA-X43 5A-TK,1983).13. L. Pouzin, "Presentation and Major DesignAspects of the Cyclades Computer Net-.work," Th ird IEEEjA CM Data CommunicationSymposium (November 1973):80-87.14. R. Jain and W. Hawe, "Performance Analysisand Modeling of Digital's NetworkingArchitecture," Digital Technical journal(September 1986, this issue) : 25-34.15. DECnet Digital Network ArchitectureDigital Data Communications MessageProtocol (DDCMP) Functional Specification,Version 4. 1. 0 (Bedford: Digital16.17.18.19.20.21.22.23.24.25.Equipment Corporation, Order No.AA-K175A-TK, 1984) .CCITT Recommendation X. 25, CCITTYellow Book , vol. VIII.2 (Geneva: lnternationalTelecommunications Union, 1981).Standard ISO 8208 fo r Information ProcessingSystems, "X.25 Packet Level Protocolfor Data Terminal Equipment," InternationalStandards Organization ( 198 5) .The Ethernet: A Local Area Network, DataLink Layer and Physical Layer Specifications,Version 2. 0 (Digital Equipment Corporation,Intel Corporation, and XeroxCorporation, Order No. AA-K759B-TK,1982).IEEE Project 802 Local Area NetworkStandards , "IEEE Standard 802.3CSMA/CD Access Method and PhysicalLayer Specifications," Approved IEEE Standard802.3-1985, ISO/DIS 8802/3 Ouly1983).J. Schoch and J. Hupp, "Measured Performanceof an Ethernet Local Area Network,''Communications of the ACM, vol . 23,no. 12 (December 1980) : 711-721.F. Tobagi and B. Hunt, "Performance Analysisof Carrier Sense Multiple Access withCollision Detection," Computer Networks, vol . 4, no. 5 (October/November1980): 245-259.W. Hawe, M. Kempf, and A. Kirby, "TheExtended Local Area Network Architectureand LANBridge 100," Digital Technicaljo urnal (September 1986, this issue) :54-72.IEEE Project 802 Local Area Networks ,"Medium Attachment Unit and BasebandMedium Specifications, 1 OBASE2," IEEEP802.3/83j0.21E, Section 10.IEEE Project 802 Local Area Networks ,"Broadband Medium Attachment Unit andBroadband Medium Specifications," IEEEwP802.3j84j0.46B, Section 11.Standard ISC 7498 for Information ProcessingSystems , "Open International StandardsOrganization ( 1982).24. Digital Technical JournalNo. 3 September 1986
Page 1 and 2: Netwo;king ProductsDigital Technica
Page 3 and 4: Editor's IntroductionRichard W. Bea
Page 5 and 6: BiographiesRaj Jain Raj Jain gradua
Page 7: BiographiesDavid R. Oran Dave Oran
Page 10 and 11: increase the sizes of networks, we
Page 12: New Productsmust be able to coexist
Page 15 and 16: A Digital Network Architecture Over
Page 21 and 22: ---A Digital Network Architecture O
Page 23: A Digital Network Architecture Over
Page 27 and 28: Performance Analysis and Modeling o
Page 29 and 30: ---Performance Analysis and Modelin
Page 31 and 32: Performance Analysis and Modeling o
Page 33 and 34: ---Performance Analysis and Modelin
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
Page 49 and 50: The DECnetjSNA Gateway Productopera
Page 51 and 52: The DECnetjSNA Gateway ProductSegme
Page 53 and 54: The DECnetjSNA Gateway Product• O
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 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Paul R. Beckjames A. KryckaThe DECn
Page 91 and 92:
The DEC net- VA X Product - An Inte
Page 93 and 94:
The DECnet- VA X Product - An Integ
Page 95 and 96:
The DECnet- VAX Product - An Integr
Page 97 and 98:
The DEC net- VA X Product - An Inte
Page 99 and 100:
The DECnet- VAX Product - An Integr
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 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
The NMCCjDECnet Monitor Design5. Op
Page 133 and 134:
Th e NMCCjDECnet Monitor DesignFigu
Page 135 and 136:
The NMCCjDECnet Monitor DesignKERNE
Page 137 and 138:
The NMCCjDECnet Monitor Designinto
Page 139 and 140:
The NMCCj/JECnet Monitor DesignThe
Page 141 and 142:
The NMCCjDECnet Monitor Designcan s
Page 143 and 144:
Editorial StaffEditor - Richard W.
show all

DTJ Number 3 September 1987 - Digital Technical Journals

Create successful ePaper yourself

Delete template?

Save as template?