1. 1 Networking Media (Tangible)

2. 2 Define and understand technical terms related to cabling, including attenuation, crosstalk, shielding, and plenum Identify three major types of both network cabling and wireless network technologies Understand baseband and broadband transmission technologies and when to use each continued Learning Objectives

3. 3 Decide what kinds of cabling and connections are appropriate for particular network environments Describe wireless transmission techniques used in LANs Describe signaling technologies for mobile computing

4. 4 Network Cabling: Tangible Physical Media Provides a medium across which network data can travel in the form of a physical signal, whether it is a type of electrical transmission or some sequence of light pulses

5. 5 Primary Cable Types Coaxial cable Twisted-pair (TP) cable  Unshielded (UTP)  Shielded (STP) Fiber-optic

6. 6 General Cable Characteristics Bandwidth rating  Number of bits that can be transferred per second Maximum segment length  Signals weakens along with the distance they travel  Weakened signals should be restored Maximum number of segments per internetwork  Networks are subject to some kind of maximum tolerable delay, after which it’s assumed signals can no longer arrive continued

7. 7 General Cable Characteristics Maximum number of devices per segment  Each device insertion will typically cause signal attenuation on a cable segment and this is called insertion loss Interference susceptibility  Each type of cable may be susceptible to other signals that may be present in the environment, e.g., electromagnetic interference (EMI) or radio frequency interference (RFI)  We assume 4 levels of susceptibility, namely, none, low, moderate, and high continued

8. 8 General Cable Characteristics Connection hardware  Different cables are associated with different connectors Cable grade  The rate of a cable in transferring data  Building and fire codes may require specific cabling requirements such as the combustibility and toxicity of the sheath material of a cable, as well as the insulation that cover the cable  Plenum-rated cable is of low combustibility and it generates relatively nontoxic fumes when burned continued

9. 9 General Cable Characteristics Bend radius  Bending of cable of certain types is more prone to damage than others Material costs  Some cable is more expensive to build than others Installation costs  Labor and auxiliary equipment can easily cost more than the cable when installing a network

10. 10 Primary Techniques for Sending Signals across a Cable Baseband transmission Broadband transmission  This has nothing to do with broadband and narrowband internet connections.

11. 11 Baseband Transmission Uses digital signals sent over a cable without modulation Sends binary values (0s and 1s) as pulses of different voltage levels (i.e., digital transmission) Entire bandwidth of the cable is used to transmit a single data signal Limits any single cable strand to half-duplex transmission continued

12. 12 Baseband Transmission Signal flow can be bi-directional Uses repeaters to restore the signal to its original strength and quality before retransmitting it to another cable

13. 13 Broadband Transmission An analog transmission technique which may use multiple communication channels simultaneously Each data channel is represented by modulation on a particular frequency band, for which sending or receiving equipment must be tuned, like a TV set Signal flow is one-way only; two channels are necessary for computers to send/receive data continued

14. 14 Broadband Transmission Primary approaches to supporting two-way broadband communications  Mid-split broadband  Dual-cable broadband Uses amplifiers to detect weak signals, strengthen those signals, and then rebroadcast them; noise may be amplified too Offers higher bandwidths, but generally more expensive than baseband systems

15. 15 Coaxial Cable Uses a center conductor – wrapped by an insulating layer, surrounded by a braided wire mesh and an outer jacket or sheath -- to carry high-bandwidth signals such as network traffic or broadcast television frequencies

16. 16 Coaxial Cable Uses shielding to increase the viability of the signals that pass through a cable by absorbing stray electronic signals or fields Less susceptible to interference and attenuation than twisted-pair cabling, but more so than fiber-optic A connector must cap each end of the cable, and a terminator must screw into each end

17. 17 Types of Coaxial Cable for Ethernet Thin Ethernet (thinnet, thinwire, cheapernet, 10Base2) Thick Ethernet (thicknet, thickwire, 10Base5)

18. 18 Thinwire Ethernet Thin, flexible cable about 0.2” in diameter Easy to work with Relatively inexpensive to build or buy Well suited for small or constantly changing networks Uses BNC T-connectors to attach directly to networking devices and computers’ network adapter cards

19. 19 Thinwire Ethernet

20. 20 Radio Government (RG) Specifications Coaxial cable designation that reflects coaxial cable’s original use as a conveyance for radio frequency data and signals

21. 21 Radio Government (RG) Specifications

22. 22 Thinwire Ethernet Cable

23. 23 Thickwire Ethernet Uses a rigid cable about 0.4” in diameter (“frozen yellow garden hose”) Rarely used except as a backbone for a new network installation (due to expense, large diameter, and lack of flexibility) Uses a vampire tap to attach a device to the cable, which in turn attaches to a transceiver; transceiver attaches to a drop or transceiver cable that plugs into an attachment unit interface (AUI)

24. 24 Attaching to Thinwire Ethernet Cable

25. 25 Attaching to Thickwire Ethernet Cable

26. 26 Running Thickwire Cable

27. 27 Thickwire Ethernet Cable

28. 28 Coaxial Cable Characteristics Can handle moderate to serious bandwidth Supports intermediate to moderately long cable runs Relatively affordable Resistant to interference; relatively safe from electronic “eavesdropping”

29. 29 Twisted-pair Cable Consists of one or more pairs of insulated strands of copper wire twisted around one another Importance of twists  Improve resistance to interference  Limit the influence of crosstalk

30. 30 Types of TP Cable Unshielded twisted-pair (UTP)  Contains one or more pairs of insulated wires within an enclosing insulating sheath  Follows the ANSI/EIA/TIA 568 standard  Prone to crosstalk Shielded twisted-pair (STP)  Encloses each pair of wires within a foil shield, as well as within an enclosing insulating sheath  Supports higher bandwidth over longer distances than UTP  Has no set of standards

31. 31 Types of TP Cable

32. 32 UTP cable (1/3) Most popular form of local area network cable UTP cables are classified to a number of categories such that each of them is associated with a different specification which include its maximum data transmission speeds

33. 33 UTP cable (2/3) Category 6 UTP cable can support up to 1 gigabit per second, with signaling rates up to 250 MHz; specification of category 7 UTP cable is being drafted UTP is particularly prone to crosstalk and the shielding included with STP is designed specifically to alleviate the problem Like STP, it employs RJ-45 telephone connectors to plug into computer network interfaces or other networked devices

34. 34 UTP cable (3/3) Keep cables run within 295 feet For more information and FAQs about UTP cable, see http://www.lanshack.com/cat5e-tutorial.asp http://www.lanshack.com/cat5e-tutorial.asp

35. 35 Twisted-pair Network Cabling Schemes Commonly employ RJ-45 telephone connectors

36. 36 10BaseT’s Networking Characteristics

37. 37 Fiber-optic Cable Uses pulses of light sent along a light- conducting fiber at the heart of the cable to transfer information Sends data in one direction only; two cables are required to permit data exchange in both directions Consists of a slender cylinder of glass fiber(s), called the core, surrounded by a concentric layer of cladding material and then by an outer sheath

38. 38 Fiber-optic Cable Kevlar ® is a kind of nylon that is used makes bullet-proof vest and puncture resistant bicycle tires. (See http://www.psrc.usm.edu/macrog/fiberopt/of.htm for more information about what optic fibers are made of.)http://www.psrc.usm.edu/macrog/fiberopt/of.htm

39. 39 Primary Types of Fiber-optic Cables Single-mode cables  Include only one glass fiber at the core  Cost more  Work with laser-based emitters but span the longest distances Multi-mode cables  Incorporate two or more glass fibers at the core  Cost less  Work with light emitting diodes (LEDs) but span shorter distances (< 2 km)

40. 40 Fiber-optic Cable Advantages Immune to interference Highly secure; eliminates possibility of electronic eavesdropping Good medium for high-bandwidth, high- speed, long-distance data transmissions

41. 41 Fiber-optic Cable Drawbacks High cost to install Difficult installation  Cable must be precisely polished on the cut ends  Cables are sensitive to bending or shearing forces  Sophisticated optical tests are needed to ensure proper cable alignment to sensors and emitters  Fiber-optic system's incompatibility with current electronic hardware systems requires that communication hardware systems be somewhat retrofitted to the fiber-optic networks. Much of the speed that is gained through optical fiber transmission can be inhibited at the conversion points of a fiber-optic chain.

42. 42 Fiber-optic Cable Characteristics Remark: The maximum bandwidth of an optical cable has been increased tremendously over years. Some can support more than 1 terabit per second.

43. 43 Fiber-optic Media Connectors Number of connector options for fiber-optic media varies with the type of light-emitting source and light-detecting sensors being used  ST (straight tip)  SC (straight connection)  MIC (medium interface connector) for FDDI  SMA (subminiature type A)

44. 44 Reference Website for Fiber- optic Data Communications For more information about fiber-optic data communications, visit http://www.lascomm.com/tutorial.htm http://www.lascomm.com/tutorial.htm Specifically, read the section on wave division multiplexing.

45. 45 Cable Selection Criteria Bandwidth Budget Capacity (data, bandwidth) Environmental considerations Placement  Where will the cables run? Scope  Number of devices to be connected to the network Span  Distance that the network needs to span

46. 46 Comparison of General Cable Characteristics