1. © Copyright 1997, The University of New Mexico 2-1 Definitions Architecture Proprietary Systems De facto Standards Standards

2. © Copyright 1997, The University of New Mexico 2-2 Definitions Architecture: –The science, art, or profession of designing and constructing buildings, bridges, etc. –Any framework, system, etc. –The design and interaction of components of a computer or computer systems

3. © Copyright 1997, The University of New Mexico 2-3 Definitions Proprietary Systems –Privately owned and operated –Held under patented, trademark, or copyright by a private person or company De facto Standards –Existing or being such in actual fact though not by legal establishment –Official recognition Standards –Something established for use as a rule or basis of comparison in measuring or judging capacity, quantity, content, extent, value, quality, etc.

4. © Copyright 1997, The University of New Mexico 2-4 Definitions Rules and conventions for the exchange of information –Open Systems Who makes the rules and conventions? –Many local, regional, and international organizations –ISO, ITU, IEEE, ANSI, ECMA

5. © Copyright 1997, The University of New Mexico 2-5 Definitions Open Systems Interconnection Standards –Packet Switched Public Data Network (PSPDN) –Circuit Switched Public Data Network (CSPDN) –Public Switched Telephone Network (PSTN) –Integrated Services Digital Network (ISDN) –Local Area Network (LAN)

6. © Copyright 1997, The University of New Mexico 2-6 Definitions V-series –Connecting equipment to a Public Switched Telephone Network (PSTN) X-series –Connecting equipment to a Public Switched Data Network (PSDN) I-series –Connecting equipment to an Integrated Services Digital Network (ISDN)

7. © Copyright 1997, The University of New Mexico 2-7 Internetworking Architecture Models OSI Model 3-Layer Model TCP/IP Model

8. © Copyright 1997, The University of New Mexico 2-8 OSI Model International Organization for Standardization (ISO) –Open System Interconnection (OSI) Model, provides a framework Application Presentation Session Transport Network Data Link Physical Boundary Technology independent Technology dependent

9. © Copyright 1997, The University of New Mexico 2-9 OSI Model Physical Layer (1) –deals with mechanical, electrical and procedural interfacing –provides collision detection –specifies cables, connectors, and other components –transmits raw information over communication channel –establishes, maintains, and disconnects physical links –includes software device drivers for communication interfaces

10. © Copyright 1997, The University of New Mexico 2-10 OSI Model Data Link Layer (2) –provides reliable transfer of data –breaks data (packets) into frames –adds bits for error detection/correction –manages access to and use of the channel –solve problems caused by lost, damaged, and duplicate frames –sends acknowledgments –adds flags to indicate beginning and end of message –connectionless or connection oriented services –IEEE MAC and LLC support

11. © Copyright 1997, The University of New Mexico 2-11 OSI Model Network Layer (3) –establishes, maintains and terminates connections –determines how packets are routed –divides transport messages into packets and reassembles them –performs congestion control, flow control –provides virtual circuit or datagram services –recognizes message priorities –sends messages in proper order –handles internetworking

12. © Copyright 1997, The University of New Mexico 2-12 OSI Model Transport Layer (4) –establishes reliable end-to-end transport session (error detection and recovery), once path has been established –fragmentation of message into packets (if not handled by layer 3) –multiplexing of several sessions from same source and all going to same destination –creates distinct network connections –monitors quality of service –disassembles and assembles session messages –flow control (if not done by layer 3)

13. © Copyright 1997, The University of New Mexico 2-13 OSI Model Session Layer (5) –establishes and controls system-dependent issues –establishes and terminates connections –accounting service –user interface into the network –authentication of users –controls dialogue, organizes and synchronizes

14. © Copyright 1997, The University of New Mexico 2-14 OSI Model Presentation Layer (6) –data encryption, security, compression and code conversion –make sure data is encoded in standard form (ASCII) –handles pass-through of services from session to application layer

15. © Copyright 1997, The University of New Mexico 2-15 OSI Model Application Layer (7) –login, password check –agreement on semantics for information exchange –file transfer, access and management –message handling, email –job transfer and manipulation –directory service –system management –industry protocols –database access and management –virtual terminals

16. © Copyright 1997, The University of New Mexico 2-16 OSI Model Application Presentation Session Transport Network Data Link Physical Application Presentation Session Transport Network Data Link Physical Data Physical

17. © Copyright 1997, The University of New Mexico 2-17 3-Layer Model 7-layer OSI to 3-layer mapping –System integrators approach Application Presentation Session Transport Network Data Link Physical Network Services Network Protocols Network Infrastructure

18. © Copyright 1997, The University of New Mexico 2-18 TCP/IP Model TCP/IP Protocol Suite, ARPANET (DARPA) Application Transport (TCP,UDP) Internet (IP) Network Access Physical

19. © Copyright 1997, The University of New Mexico 2-19 OSI to TCP/IP Models 7-layer OSI and TCP/IP Protocol Architectures Application Presentation Session Transport Network Data Link Physical Transport (TCP,UDP) Network Access Application Internet (IP) Physical

20. © Copyright 1997, The University of New Mexico 2-20 Internetworking Standards Proprietary Systems De facto Standards Standards Based Solutions

21. © Copyright 1997, The University of New Mexico 2-21 Internetworking Standards Proprietary Systems –Hewlett-Packard –DARPA TCP/IP –Sun Network Services –Novell NetWare –IBM/SNA –DEC/DECnet Phase IV –3Com –Xerox/XNS –IBM/SNA –Apple/AppleTalk –Banyan VINES

22. © Copyright 1997, The University of New Mexico 2-22 Internetworking Standards De facto Standards –TCP/IP –Ethernet V1 & V2 –X-Windows –Unix –WIN95 –NT

23. © Copyright 1997, The University of New Mexico 2-23 Internetworking Standards Standards Based Solutions –IEEE: 802.3/CSMA/CD, 802.5/Token Ring, 802.2/LLC, etc. –ANSI: FDDI, etc. –CCITT: V.35, X.25, Frame Relay, etc. –ISO-ITU: 8802/3, 8802/5, 9314, V.35, etc. –EIA: RS-232, RS-449, etc. –ATM Forum

24. © Copyright 1997, The University of New Mexico 2-24 Network Terminology Modems: OSI-Layer 1 device. Modulator- demodulator, device that converts digital and analog signals, allows data to be transmitted over voice grade telephone lines (PSTN). Modem standards include: V.21, V.22 bis, V.32 bis, V.34, V.42 bis, etc. Repeaters: OSI-Layer 1 device. Regenerates and propagates electrical signals between two network segments. Repeater standards include: Ethernet, IEEE 802.3 (10Base5, 10Base2, 10BaseT, 10BaseFX), FDDI, ATM, etc.

25. © Copyright 1997, The University of New Mexico 2-25 Network Terminology Bridges: OSI Layer 2 device. Connects and passes packets between network segments that use similar and different communication protocols. Bridge standards include: IEEE 802.1d, Transparent Source Routing, Translational, etc. Switches: OSI Layer 2 device. Very fast bridge. Switch Standards include: ATM, Frame Relay, SMDS, ISDN, etc.

26. © Copyright 1997, The University of New Mexico 2-26 Network Terminology Routers: OSI Layer 3 device. Forwards packets from one network to another based on metrics that will allow for optimum path. Router standards include: RIP, OSPF, ISIS, BGP, EGP, etc. Gateways: OSI Layers 1-7 device. Special- purpose device that converts information from one protocol stack to another.

27. © Copyright 1997, The University of New Mexico 2-27 Network Terminology 4 types of equipment –Repeaters - layer 1 –Bridges - layer 2 –Routers - layer 3 –Gateways - layers 1-7 All use functionality of lower layers

28. © Copyright 1997, The University of New Mexico 2-28 Repeaters Used to extend a LAN Connects two cable segments Amplifies and sends all electrical signals between segments Stations do not know whether a repeater separates them IEEE 802.3: max. 4 repeaters between any two stations

29. © Copyright 1997, The University of New Mexico 2-29 Repeaters repeater max. Ethernet segment direct connection

30. © Copyright 1997, The University of New Mexico 2-30 Bridges Simplest form to extend a LAN LANs can be of more than one type Interconnect LAN and MAN Past: used between LANs with identical protocols (physical, MAC) Present: used between LANs with different protocols

31. © Copyright 1997, The University of New Mexico 2-31 Bridges bridge stations standard connection (same as computers)

32. © Copyright 1997, The University of New Mexico 2-32 Switches Switched LAN, single electronic device that transfers frames among many stations Hub: simulates a single shared medium –at most two computers can communicate at a time –max. possible bandwidth is R (rate a single computer can send data)

33. © Copyright 1997, The University of New Mexico 2-33 Switches Switch: simulates a bridged LAN with one station per segment –each computer is in a simulated LAN segment –as many as 1/2 of stations can send data at the same time (1/2 send, 1/2 receive) –max. possible bandwidth is RN/2, N is number of stations connected

34. © Copyright 1997, The University of New Mexico 2-34 Introduction to Transmission Media & LAN Technologies Transmission Media & Cabling Systems LAN Technologies

35. © Copyright 1997, The University of New Mexico 2-35 Introduction to Transmission Media Signals Data Transmission Transmission Media Cabling Systems

36. © Copyright 1997, The University of New Mexico 2-36 Introduction LAN Technologies 10/100/1000 Mbps Ethernet 100 Mbps FDDI 155/620 Mbps ATM 4/10/45 Mbps Wireless