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Cabling and Topology Chapter 3. Objectives Explain the different types of network topologies Describe the different types of network cabling Describe.

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Presentation on theme: "Cabling and Topology Chapter 3. Objectives Explain the different types of network topologies Describe the different types of network cabling Describe."— Presentation transcript:

1 Cabling and Topology Chapter 3

2 Objectives Explain the different types of network topologies Describe the different types of network cabling Describe the IEEE networking standards

3 Overview

4 Three Parts to Chapter 3 Network Topology Most common standardized cable types IEEE Committees for network technology standards

5 Topology

6 Network topology –The way that cables and other pieces of hardware connect to one another

7 Bus topology –Single bus cable –Connects all computer in a line Ring topology –Central ring of cable –Connects all computers in a ring Bus and Ring

8 Figure 3.1 Bus and ring topologies

9 Figure 3.2 Real-world bus topology

10 Data flow –Bus topology Data flows from each computer onto the bus Termination required at ends to prevent data reflection –Ring Topology Data flows from one computer to next one in circle No end of cable and no need for termination

11 Figure 3.3 Terminated bus topology

12 Figure 3.4 Ring topology moving in a certain direction

13 Problem with Bus and Ring –Entire network stops working if the cable is broken at any point.

14 Figure 3.5 Nobody is talking!

15 Star topology has a central connection for all computers Fault tolerance – benefit over bus and ring Was not successful early on –More expensive than bus and ring –Difficult to redesign early bus and ring hardware Star

16 Figure 3.6 Star topology

17 Hybrid topology combines topologies –Physical topology How cables physically look –Signaling topology How the signals travel electronically Hybrids

18 Star-ring topology –Physical star + signaling ring –Ring shrunk down into a hub-like box –Cables connect to the hub Star-bus topology –Physical star + signaling bus –Segment (bus) shrunk down into a hub-like box –Cables connect to the hub

19 Figure 3.7 Shrinking the ring

20 Figure 3.8 Shrinking the segment

21 Mesh topology –Every computer connects to every other computer via two or more routes Two types of mesh topology –Partially-meshed topology At least two machines have redundant connections –Fully-meshed topology Every computer connects directly to every other computer Most fault tolerant Mesh and Point-to-Multipoint

22 Figure 3.9 Mesh and point-to-multipoint

23 Figure 3.10 Partially- and fully-meshed topologies

24 Point-to-multipoint topology –A single system is a common source Figure 3.11 Comparing star and point-to-multipoint

25 Two computers connect directly No need for a central hub Wired or wireless Point-to-Point Figure 3.12 Point-to-Point

26 Topology is only one feature of a network Other network features –What is the cable made of? –How long can it be? –How do machines decide which machine should send data and when? Parameters of a Topology

27 Network technology –A practical application of a topology, and other technologies that comprise a network –Examples 10BaseT 1000BaseF 10GBaseLX

28 Cabling

29 A central conductor wire Surrounded by an insulating material Surrounded by a braided metal shield Coaxial Cable Figure 3.13 Cutaway view of coaxial cable

30 Outer mesh layer of coaxial cable –Shields transmissions from electromagnetic interference (EMI) Figure 3.14 Coaxial cable showing braided metal shielding

31 Coaxial connectors in older networks –Bayonet-style BNC Connectors –Vampire taps pierced the cable Figure 3.15 BNC connector on coaxial cable

32 Connecting cable modems –F-type screw-on connector Figure 3.16 F-type connector on coaxial cable

33 RG rating for coaxial cable –Developed by military –RG-6 is predominate cable today –RG-59 cable is rarely used Figure 3.17 RG-6 cable

34 Coaxial cable Ohm rating –Relative measure of resistance –RG-6 and RG-59 are rated at 75 Ohms Figure 3.18 Ohm rating (on an older RG-58 cable used for networking)

35 Splitting coaxial cable Figure 3.19 Coaxial splitter Figure 3.20 Barrel connector

36 Extending coaxial cable Figure 3.20 Barrel connector

37 Most common network cabling Twisted pairs of cables, bundled together Twists reduce crosstalk interference Twisted Pair

38 Shielding protects from electromagnetic interference (EMI) Needed in locations with excessive EMI Most common is IBM Type 1 cable Shielded Twisted Pair (STP) Figure 3.21 Shielded twisted pair

39 Most common Twisted pairs of wires with plastic jacket Cheaper than STP Also used in telephone systems Unshielded Twisted Pair (UTP) Figure 3.22 Unshielded twisted pair

40 Category (CAT) ratings are grades of cable ratings Rated in MHz Most common categories are in Table 3.1 CAT Ratings

41 CAT Ratings for UTP CATMax RatingFrequencyMax BandwidthStatus with TIA/EIA CAT1<1 MHzAnalog phone lines onlyNo longer recognized CAT24 MHz4 MbpsNo longer recognized CAT316 MHz16 MbpsRecognized CAT420 MHz20 MbpsNo longer recognized CAT5100 MHz100 MbpsNo Longer recognized CAT5e100 MHz1000 MbpsRecognized CAT 6250 MHz10000 MbpsRecognized Table 3.1

42 Bandwidth is the maximum amount of data that will go through a cable per second 100 MHz originally translated to 100 Mbps With bandwidth-efficient encoding –CAT 5e at 100 MHz = 1,000 Mbps max bandwidth –CAT 6 at 250 MHz = 10,000 Mbps UTP Bandwidth

43 Look on the box Using the Correct Cable Figure 3.23 CAT level marked on box of UTP CAT level

44 Look on the cable Using the Correct Cable Figure 3.24 CAT level on UTP CAT level

45 RJ-11 (two pairs of wires) for telephones RJ-45 (four pairs of wires) for networks Register jack (RJ) connectors Figure 3.25 RJ-11 (top) and RJ-45 (bottom) connectors

46 Fiber-optic cable transmits light Not affected by EMI Excellent for long-distance transmissions –Single copper cable works up to a few hundred meters –Single fiber-optic cable works up to tens of kilometers Fiber-Optic

47 Core: the glass fiber Cladding: reflects signal down the fiber Buffer: gives strength Insulating jacket: protects inner components Composition of Fiber-Optic Figure 3.26 Cross section of fiber-optic cabling

48 Two-number designator –Core and cladding measurements –62.5/125 μm Standardization of Fiber-Optic

49 One for sending One for receiving Cable may be connected together like a lamp cord Often used in cable pairs Figure 3.27 Duplex fiber-optic cabling

50 Two possible light sources –Light Emitting Diodes (LEDs) – called multimode Usually 850 nm wavelength –Lasers – called single-mode Prevents modal distortion (a problem with multimode) High transfer rates over long distances 1310 or 1550 nm wavelength Fiber-Optic Light Sources

51 ST: bayonet-style SC: push-in LC: duplex Fiber-Optic connectors

52 Figure 3.28 From left to right: ST, SC, and LC fiber-optic connectors

53 Classic Serial –RS-232 recommended standard (RS) Dates from 1969 Has not changed significantly in 40 years Usually 850 nm wavelength –Most common serial port is 9-pin, male D-subminiature connector –Slow data rates: about 56,000 bps –Only point-to-point connections Other Cables

54 Figure 3.29 Serial port Serial port

55 Parallel –Up to 2 Mbps –Limited to point-to-point –IEEE 1284 committee sets standards Figure 3.30 Parallel connector

56 FireWire –IEEE 1394 standard –Limited to point-to-point –Very fast – up to 800 Mbps –Unique connector

57 Figure 3.31 FireWire connector

58 Underwriters Laboratories and the National Electrical Code (NEC) –Polyvinyl chloride (PVC) rating has no significant fire protection Lots of smoke and fumes –Plenum-rated cable Less smoke and fumes Costs three to five times as much as PVC-rated cable –Riser-rated cable for vertical runs Cable Fire Ratings

59 Networking Industry Standards – IEEE

60 Institute of Electrical and Electronics Engineers (IEEE) defines standards –802 Working Group began in February of 1980 Defines frames, speed, distances, and types of cabling for networks IEEE 1284 committee sets standards for parallel communications

61 Figure 3.32 Parallel cable marked IEEE 1284 – compliant

62 IEEE 802 Subcommittees IEEE 802LAN/MAN Overview & Architecture IEEE 802.1Higher Layer LAN Protocols 802.1sMultiple Spanning Trees 802.1wRapid Reconfiguration of Spanning Tree 802.1xPort Based Network Access Control IEEE 802.2Logical Link Control (LLC); now inactive IEEE 802.3Ethernet 802.3ae10 Gigabit Ethernet IEEE 802.5Token Ring;; now inactive IEEE Wireless LAN (WLAN); specifications, such as Wi-Fi IEEE Wireless Personal Area Network (WPAN) IEEE Broadband Wireless Access (BWA); specification for implementing Wireless Metropolitan Area Network (Wireless MAN); referred to also as WiMax IEEE Resilient Packet Ring (RPR) IEEE Radio Regulatory Technical Advisory Group IEEE Coexistence Technical Advisory Group IEEE Mobile Broadband Wireless Access (MBWA) IEEE Media Independent Handover IEEE Wireless Regional Area Networks Table 3.2


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