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Ethernet Networking Technology Overview and Network Design

Ethernet Networking Technology Overview and Network Design. 1. 2. 3. Agenda. 10 Mbit/s Ethernet technology. What is a Local Area Network?. Overview of network technologies. 4. 5. 6. Agenda. 100 Mbit/s Ethernet technology. Switching technology. 1000 Mbit/s Ethernet technology. 1. 2.

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Ethernet Networking Technology Overview and Network Design

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  1. Ethernet NetworkingTechnology Overviewand Network Design

  2. 1 2 3 Agenda 10 Mbit/s Ethernet technology What is a Local Area Network? Overview of network technologies

  3. 4 5 6 Agenda 100 Mbit/s Ethernet technology Switching technology 1000 Mbit/s Ethernet technology

  4. 1 2 3 4 5 6 What is a Local Area Network? Overview of network technologies 10 Mbit/s Ethernet technology 100 Mbit/s Ethernet technology Switchingtechnology 1000 Mbit/s Ethernet technology

  5. What is a Local Area Network? • Definition of a LAN • Why use a LAN? • Characteristics of LANs • LAN Topologies and Structured Cabling • Repeaters, Bridges and Routers • Switching and Segmenting networks • Virtual LANs

  6. Definition of a LAN • A LAN is a system of cabling, equipment and software which allows computers to share and exchange data electronically, using an agreed format (protocol), within a ‘local’ area

  7. Other types of Area Network • WAN - Wide Area Network • Interconnecting LANs and users over long distances, often on a public network • MAN - Metropolitan Area Network • Interconnecting LANs and users within a city area, typically by dedicated fibre optics

  8. Why use a LAN? • An island of information

  9. Why use a LAN? • Users can share data • Saves time, makes work more efficient • Connect different computers together • A LAN can be the common denominator • Users can share resources (printers, storage) • Saves money on expensive capital equipment • Centralised administration • E-mail, Internet and Multimedia • Reduces paper documents, better information

  10. LAN Characteristics • How are LANs characterised? • By speed (bandwidth) • By topology • By special features • By their target application • LAN technologies are optimised for certain application areas

  11. Network Topologies BUS Nodes are all connected to the same circuit RING Nodes are connected in a daisy chain

  12. T Network Access Methods Contention Nodes try to use the network at any time Token Passing Nodes wait their turn to use the network

  13. Network Wiring Topologies Bus Ring STAR wiring topology Nodes are physically wired to a central point

  14. Structured Cabling • Uses UTP for floor wiring • Uses Fibre for backbone connections • Many more wires installed than users - flood wiring • All cables star-wired from central points • Flexible, resilient, future proof, easy moves

  15. Connecting nodes to a LAN Network Operating System (NOS) Software To other hosts on the network Cable Network Hub “DTE” MACAddress Communication by an agreedProtocol Network Interface Card (NIC)

  16. Network Protocols • Protocols are the “language” used on a network • The network just sends and receives packets of data, while the protocol ensures that the right data is delivered to the right place • Using common protocols allows computers from different manufacturers to exchange data

  17. Protocols defined... A protocol is a common system where both parties acknowledge the same rules governing communication.

  18. Interconnecting Networks • Three ways to join network segments together: Repeaters, Bridges and Routers • Repeaters extend physical networks • Bridges link networks of the same type together • Routers connect networks of different types together

  19. Repeater Connecting network segments with Repeaters Repeater forwards all activity All network traffic visible to all the nodes on the network

  20. Bridge Connecting network segments with Bridges Bridge only forwards traffic intended for the other network Local Traffic stays on local segment Local Traffic stays on local segment

  21. WAN Connecting networks together with Routers Local Network Routers transfer protocol-specific traffic (e.g. IP, IPX) between different network types, e.g. across a WAN Router X.25, Frame Relay, ISDN etc. Local Traffic stays on local segments Remote Network Router

  22. Summary • Networks allow computers to share data quickly and cheaply • Networks are a combination of hardware and software • Network technologies can be shared or switched, or a mix of both

  23. 2 3 4 1 5 6 What is a Local Area Network? Overview of network technologies 10 Mbit/s Ethernet technology 100 Mbit/s Ethernet technology Switchingtechnology 1000 Mbit/s Ethernet technology

  24. Overview of Network technologies • Ethernet: 10 Mbit/s • Fast Ethernet: 100 Mbit/s • Gigabit Ethernet: 1000 Mbit/s • IBM Token Ring: 4 and 16 Mbit/s • 100VG-AnyLAN: 100 Mbit/s • FDDI: 100 Mbit/s • ATM: 25, 155 and 622 Mbit/s

  25. Ethernet Technologies • 10 Mbit/s Ethernet • One of the oldest network technologies, and still the most popular • Fast Ethernet (100 Mbit/s) • Upgrade route from 10 Mbit/s, providing higher performance • Gigabit Ethernet (1000 Mbit/s) • The next generation for servers and backbones, providing very high throughput

  26. Gigabit Ethernet • Promoted by the Gigabit Ethernet Alliance • Being standardised in IEEE 802.3z, due in 1998 • Uses same CMSA/CD technology as Ethernet, running at 1000 Mbit/s • Gigabit Ethernet on copper cabling is a special problem • High-performance backbone technology

  27. Network Technologies: Summary • Networking technologies can be classified by their access mechanism • Contention-based technologies are less efficient than other solutions, but the overall cost of ownership is lower • Ethernet covers all parts of a LAN from desktop to backbone

  28. 1 2 3 4 5 6 What is a Local Area Network? Overview of network technologies 10 Mbit/s Ethernet technology 100 Mbit/s Ethernet technology Switchingtechnology 1000 Mbit/s Ethernet technology

  29. 10 Mbit/s Ethernet • Origins of 10 Mbit/s Ethernet • How Ethernet works • CSMA/CD operation • Full and Half Duplex modes • Ethernet frames • Components of an Ethernet LAN • Software and Network Interface Card • Transceivers and Cabling • Repeaters and Hubs • Switches

  30. Origins of 10 Mbit/s Ethernet • Original system design by DEC, Intel, and Xerox (hence DIX Ethernet) • Designed in 1970’s, first specifications 1980 • Ethernet type II adopted as IEEE 802.3 10BASE-X, first published in 1985

  31. How Ethernet works 1 • All transmission is at 10 million bits per second (0’s or 1’s) • Users are connected to common cable (media) • Access to the media is by a simple set of rules known as Carrier Sense Multiple Access / Collision Detect (CSMA/CD). • Listen for silence on cable (CS) • Transmit data without waiting your turn (MA) • If you hear someone else talking - stop sending, and wait for a random time before trying again (CD)

  32. How Ethernet Works 2 1. Send when the network is quiet 2. Collision is detected if another station sends 3. Both stations wait for a random time 4. Re-send again when the network is quiet

  33. Full and Half Duplex 1 • Normal Ethernet only allows one frame on the cable at a time (Half Duplex) • UTP and fibre optics use separate circuits for Transmit and Receive • Full Duplex allows frames to be sent and received at the same time over a point-to-point link • Both ends must support Full Duplex • Repeaters cannot support full duplex

  34. Full and Half Duplex 2 Half Duplex Operation Full Duplex Operation Transmit only - OK Transmit and Receiveat same time on separatecircuits - OK Receive only - OK Transmit and Receive = Collision

  35. How Data is Transferred • All data is transferred in ‘packets’ • A packet of data has addressing details at the start, and error checking data at the end. This is known as a ‘frame’ • Moving data in small pieces gives everyone an equal chance to get their data through • Smaller packets are more likely to be delivered without errors

  36. The Ethernet Frame SOFdelimiter DestinationMAC Address Type/length Data 46 - 1500 Bytes 2 6 Bytes 6 bytes 4 Preamble Source MAC Address CRC (checksum) • Preamble allows timing alignment • Start Of Frame delimiter indicates start of frame • CRC (Cyclic Redundancy Check) is a checksum to ensure the frame was received OK • Total frame length varies from 64 to 1,518 bytes (after SOF delimiter)

  37. Components of an Ethernet LAN Software Point-to-point link cable (integral XCVR) Network Interface card Hub:Repeater, Bridge, SwitchorRouter Drop cable (external XCVR) Shared cable External Transceiver

  38. Network Interface Card • The Network Interface Card (NIC) contains: • the connection to the transceiver, or a built-in transceiver • circuitry for generating frames and accessing the network • the physical MAC address • a software interface to the protocol software in the host

  39. Transceivers • Transceivers provide the electrical and physical connection between the Adapter and the shared network cable AUI drop cable XCVR Thick Ethernet Cable • This type of transceiver is not used much today as most NICs have this function built in.

  40. Current Transceiver Uses • Connecting standard hub/router/switch AUI interfaces to cable media • Connecting ‘legacy’ cards to newer cabling

  41. Ethernet Cable Options The cable provides physical connection between the adapter cards. Multiple cable types are available. Cable Connector Usage Ethernet 10Base5 AUI connection viaVampire Tap Half-duplexshared cable Thick Ethernet 10Base2 Half-duplexshared cable BNC Thin Ethernet 10BaseT 100BaseTX Full-DuplexPoint-to-point link RJ45 Twisted Pair (UTP) SMA* Screw typeST BayonetSC Dual Mini 10BaseFL 100BaseFX Full-DuplexPoint-to-point link Fibre Optic * SMA now obsolete, no new equipment manufactured to support this standard

  42. Ethernet Cable Options New fibre connectors becoming widespread during 1999/2000. Lucent LC New sub-miniature SC 3M Volition VF-45 Fibre version of RJ-45 AMP MT-RJ Fibre version of RJ-45 10BaseFL 100BaseFX Full-DuplexPoint-to-point link Fibre Optic

  43. Cable Distances and Taps 10BASE5 = 10 Mbps Baseband 500 metres length (100 taps) 10BASE2 = 10 Mbps Baseband 200 (185)metres (30 Taps) 10BASE-T =10 Mbps Baseband (100 metres) Twisted pair (single Tap)

  44. 10 Mbit/s Repeaters • 10 Mbit/s Repeaters allow more users AND more distance • Repeaters do a number of tasks: • restore the signal levels (amplify signal) • ensure that collisions are recognised, and stop anyone else transmitting until it is safe

  45. Hub Hub Hub Hub Four Repeater Roule • Si può vedere l’hub come un multiport repeater. • Come nel coassiale esiste la regola dei 4 repeater negli hub a 10Mb/s

  46. Repeater Repeater Link Segment MultinodeSegment MultinodeSegment Link Segment Repeater Repeater MultinodeSegment Ethernet 5-4-3 Rule • Maximum of five segments • Maximum of four repeaters between any two nodes • Maximum of three multi-node segments

  47. Why are there Limits? • Transmission from a user down the network cable takes time. • All users must see transmission before user has transmitted half of his frame. • This may need to checked by calculating the Round Trip Delay Time. • i.e. RT Delay < time for min frame length • or time for 64 Bytes (512 Bit times) • The 5-4-3 rule is usually sufficient for 10 Mbit/s Ethernet

  48. Ethernet Hubs • Hubs provide a central connection point for networks • Commonly used with Structured Cabling Schemes

  49. Hubs and Management • Hubs can be combined to create one big repeater - stackable, chassis based • Flexible options for integrating all media types • Management features allow network supervisors to see traffic flow and solve problems fast • Other advanced features also added • e.g. security

  50. 10 Mbit/s Ethernet: Summary • Repeater • copies everything from one segment to another: collisions, fragments, all frames including broadcasts • Bridges and Switching Hubs • Selected frames including broadcasts are copied, based on the destination MAC address • Router • Copies / converts selected frames based on protocol address

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