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Ethernet

Ethernet. Need for standards Project 802 (1980, February) Easy to install Economical. Ethernet. MAC Address. Other Forms of Ethernet. FOIRL [Fibre over inter repeater links] user to connect repeaters together in order to get greater distances maximum of 1Km 10BaseF.

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Ethernet

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  1. Ethernet • Need for standards • Project 802 (1980, February) • Easy to install • Economical Chapters 4 & 5

  2. Ethernet MAC Address Chapters 4 & 5

  3. Other Forms of Ethernet • FOIRL [Fibre over inter repeater links] • user to connect repeaters together in order to get greater distances • maximum of 1Km • 10BaseF Chapters 4 & 5

  4. Other Forms of Ethernet • fiber to desktop • applies to 10Mbps CSMA/CD • star network topology • Comprised of 10BaseFB, 10BaseFL, 10BaseFP Chapters 4 & 5

  5. 10BaseFB Synchronous Backbone • also known as 10BaseFA • 2Km per segment • 30 repeater hops allowed • no connection to desktop computers Chapters 4 & 5

  6. 10BaseFL Asynchronous Active • also known as 10BaseFF • connects repeaters to DTE's • FOIRL compatible • 2Km segment Chapters 4 & 5

  7. 10BaseFP Passive • passive star topology • non FOIRL compatible • 1Km segments Chapters 4 & 5

  8. 100 Megabit Ethernet • 100Base-X • Comes from Grand Junction Networks • supported by companies like 3Com, Intel and Sun Microsystems • backward compatible with 10Mbps Ethernet • and uses the CSMA/CD protocol • is designed to work using the existing cable types Chapters 4 & 5

  9. Summary of features • based on ANSI FDDI over copper • uses MLT-3 signaling • retains CSMA/CD • uses two pairs • uses Ethernet packet format • requires no changes to existing network components, cabling, bridges • need category 5 cabling Chapters 4 & 5

  10. 100Base-VG (Voice Grade) • Designed by Hewlett Packard and AT&T • allows users to assign priority to packets (normal or high) • increases the bandwidth from 10Mbps to 100Mbps Chapters 4 & 5

  11. 100Base-VG (Voice Grade) • CSMA is not supported, instead, a proprietary technique called quadrature signaling and demand priority is used • All four pairs are used to send the packet to a hub • If more than one packet arrives at the hub at the same time, the highest priority packet is serviced first Chapters 4 & 5

  12. 100Base-VG (Voice Grade) • Typically use VIDEO with high priority • Ethernet Frame – yes • CSMA/CD – no • Voice grade UTP – yes • Uses two-level NRZ output, 5 data bits converted into 6 transmit bits • Half-duplex Chapters 4 & 5

  13. Summary of features • uses voice grade cable • supported by Microsoft, Apple, Novell, etc • signal is split over 4 pairs • data is half duplex, one direction at a time • handles time sensitive data like voice and video • CSMA/CD replaced with Demand Priority Protocol Chapters 4 & 5

  14. Summary of features • IBM and HP have worked together to expand the 100Base-VG specification to include token ring • This will support Cat3, type4 and Type5 cable • It will not require any changes to existing wiring or to bridges and routers • The advantages of 100BaseVG-AnyLan over 100BaseT are • its topology is not so limiting • traffic can be prioritized, giving better response to some users who need it • better suited to video and voice data Chapters 4 & 5

  15. 100BaseT • This is an extension of the existing Ethernet standard • 100BaseTX uses two-pair Category 5 UTP/STP cabling Chapters 4 & 5

  16. 100BaseT • 100BaseT4 uses four-pair Category 3, 4 or 5 UTP cabling • 100BaseFX uses two-strand fiber • In order to achieve the high 100Mbps rate, the collision timing associated with CSMA/CD is reduced • This means the total lengths of cabling from a workstation to another via two hubs cannot exceed 205 meters Chapters 4 & 5

  17. 100BaseT • If using fiber, a maximum distance of 405 meters from workstation to hub is allowed • 100BaseT devices are auto sensing, which means they can run at either speed • On startup, the card advertises their speed with a series of Fast Link Pulses • If a hub supports this, it will detect the FLP's, and then negotiate with the card for the highest possible speed • This can be over-ridden by network managers, who can force the slower 10Mbps mode Chapters 4 & 5

  18. Summary of features • supported by Sun, Synoptics and 3Com • uses CSMA/CD • uses Ethernet frame format • uses new signaling scheme using 3 voltage levels • 100Base-VG-AnyLAN Chapters 4 & 5

  19. Gigabyte Ethernet • 1000Base (802.3ab) • Speed 1000Mb/sec (10 times 100BaseTX) • Requires fiber or Cat 5e or Cat 6 cable • 1000Base-LX, 1000Base-SX, 1000Base-CX • 10000Base (802.3ae) • Speed 10000Mb/sec • 10G Ethernet (10GbE) • No collisions, only used on fiber Chapters 4 & 5

  20. Gigabyte Ethernet • Labeling • 10GBase-Transmission Technique • E – Extended • L – Long • S – Short Chapters 4 & 5

  21. Wireless • IEEE created the standard in 1990 • 802.11 2 mb / sec • 802.11b 11mb /sec Wi-Fi • 802.11a 108 mb /sec Wi-Fi5 • 802.11g 54 mb/sec Chapters 4 & 5

  22. Wireless • Access point – transceiver to send & receive signals • Base station for the wireless network • Links wireless and wired networks • Range – 375 feet / 115 meters • Supports over 100 users • Uses CSMA/CA Chapters 4 & 5

  23. Network Components Network Segments A specific length of cable Devices can be attached to the cable It has its own unique address It has a limit on its length and the number of devices which can be attached to it Chapters 4 & 5

  24. Token Ring Cards Look similar to Ethernet cards Token Ring cards generally have a nine pin DIN type connector to attach the card to the network cable Chapters 4 & 5

  25. Animated links http://www.corning.com/opticalfiber/discovery_center/tutorials/fiber_101/index.asp http://fcit.coedu.usf.edu/network/game/game.htm http://www.rad.com/networks/1997/nettut/firewall.html http://www.rad.com/networks/1997/nettut/start.html http://www.rad.com/networks/1997/nettut/ethernet.html Chapters 4 & 5

  26. Repeaters A signal loses strength as it passes along a cable A device called a repeater will boost the signal Electrically amplifies the signal it receives and rebroadcasts it. Chapters 4 & 5

  27. Routers • Routers were devised in order to separate networks logically • For instance, a TCP/IP router can segment the network based on IP subnets • Filtering at this level (on IP addresses) will take longer than that of a bridge or switch which only looks at the MAC layer • Most routers can also perform bridging functions • A major feature of routers, because they can filter packets at a protocol level, is to act as a firewall Chapters 4 & 5

  28. Bridges • A device that allows you to segment a large network into two smaller, more efficient networks. • Monitors the information traffic on both sides of the network so that it can pass packets of information to the correct location Chapters 4 & 5

  29. ETHERNET SWITCHES • Ethernet switches increase network performance by decreasing the amount of extraneous traffic on individual network segments attached to the switch • They also filter packets a bit like a router does • Core switches have faster throughputs than workgroup switches Chapters 4 & 5

  30. Virtual LAN • VLAN • Connecting users using logical groupings • Accomplished through software and smart switches • Security and network isolation • Similar users get connected together even if they are in different locations Chapters 4 & 5

  31. What is a Protocol? A set of rules that governs the communications between computers on a network These rules include guidelines that regulate the following characteristics of a network: access method, allowed physical topologies, types of cabling, and speed of data transfer The most common protocols are: Ethernet Local Talk Token Ring FDDI ATM Chapters 4 & 5

  32. Internet Protocols Networks (hardware) provide computers the basic ability of transferring bits from one computer to another A set of rules which all of the network's member agree on, that is a protocol Communication Protocol is a standard designed to specify how computers interact and exchange messages Chapters 4 & 5

  33. Internet Protocols Protocol usually specifies: message format how to handle errors For simplification engineers have decided to design a set of protocols, each has different responsibilities Instead of one protocol responsible for all forms of communication. The set of protocols is called a Protocol Suite covering all forms of communication as needed Chapters 4 & 5

  34. The OSI seven layers model A layering model is the most common way to divide a protocol suite to subparts and describe them individually Layering help us to have better understanding of a protocol suite Developed over 20 years ago – theoretical model Chapters 4 & 5

  35. Chapters 4 & 5

  36. Internet protocol suite PPP Point-to-Point Protocol A protocol for creating a TCP/IP connection over both synchronous and asynchronous systems Chapters 4 & 5

  37. Internet protocol suite PPP provides connections for host to network or between two routers, It also has a security mechanism PPP is well known as a protocol for connections over regular telephone lines using modems on both ends. This protocol is widely used for connecting personal computers to the Internet Chapters 4 & 5

  38. Internet protocol suite SLIP Serial Line Internet Protocol – A point-to-point protocol to use over a serial connection, a predecessor of PPP There is also an advanced version of this protocol known as CSLIP (compressed seriallineinternetprotocol) which reduces overhead on a SLIP connection by sending just a header information, increasing packet throughput. Chapters 4 & 5

  39. Internet protocol suite FTP File Transfer Protocol – FTP enables transferring of text and binary files over TCP connection. FTP allows to transfer files according to a strict mechanism of ownership and access restrictions. It is one of the most commonly used protocols over the internet now days Chapters 4 & 5

  40. Internet protocol suiteTelnet Telnet is a terminal emulation protocol, defined in RFC854, for use over a TCP connection Enables users to login to remote hosts and use their resources from the local host Chapters 4 & 5

  41. Internet protocol suite SMTPSimple Mail Transfer Protocol – Dedicated for sending E-Mail messages originated on a local host, over a TCP connection, to a remote server Chapters 4 & 5

  42. Internet protocol suite SMTP defines a set of rules which allows two programs to send and receive mail over the network The protocol defines the data structure that would be delivered with information regarding the sender, the recipient (or several recipients) and, of course, the mail's body Chapters 4 & 5

  43. Internet protocol suite HTTPHyper Text Transport Protocol – A protocol used to transfer hypertext pages across the world wide web SNMPSimple Network ManagementProtocol A simple protocol that defines messages related to network management Through the use of SNMP network devices such as routers can be configured by any host on the LAN Chapters 4 & 5

  44. Internet protocol suite UDPUser Datagram Protocol - A simple protocol that transfers datagram (packets of data) to a remote computer UDP doesn't guarantee that packets will be received in the same order they were sent UDP doesn't guarantee delivery at all Chapters 4 & 5

  45. Internet protocol suite TCPTransmission Control Protocol - A protocol that enables a computer to send data to a remote computer Unlike UDP, TCP is reliable i.e. packets are guaranteed to wind up at their target, at the correct order Chapters 4 & 5

  46. Internet protocol suite IPInternet Protocol - The underline protocol for all the other protocols in the TCP/IP protocol suite IP defines the means to identify and reach a target computer on the network Computers in the IP world are identified by unique numbers known as the IP address Chapters 4 & 5

  47. Internet protocol suite ARPAddress Resolution Protocol - In order to map an IP address into a hardware address the computer uses the ARP protocol which broadcasts a request message that contains an IP address, to which the target computer replies with both the original IP address and the hardware address NNTPNetwork News Transport Protocol - A protocol used to carry USENET posting between News clients and USENET servers Chapters 4 & 5

  48. Chapters 4 & 5

  49. Considerations When Choosing a Topology Future growth. With a star topology, expanding a network is easily done by adding another concentrator Cable type. The most common cable in schools is unshielded twisted pair, which is most often used with star topologies Chapters 4 & 5

  50. Considerations When Choosing a Topology Money. A linear bus network may be the least expensive way to install a network; you do not have to purchase concentrators Length of cable needed. The linear bus network uses shorter lengths of cable Chapters 4 & 5

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