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ITEC 370 Network Media George Vaughan. Sources for Slides. Material in these slides comes primarily from course text, Guide to Networking Essentials , Tomsho, Tittel, Johnson (2007). Other sources are cited in line and listed in reference section. TCP/IP and OSI Models.
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ITEC 370 Network Media George Vaughan
Sources for Slides • Material in these slides comes primarily from course text, Guide to Networking Essentials,Tomsho, Tittel, Johnson (2007). • Other sources are cited in line and listed in reference section.
Cable Characteristics • Bandwidth – Bits per second • Maximum Cable Length – Length before signal is unintelligible due to attenuation. • Maximum Number of Segments – Maximum number of segments (including signal regeneration equipment) before signal is too late at destination. • Maximum Number of Devices per Segment – Devices also increase attenuation (insertion loss). • Interference Susceptibility – Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI). • Connection Hardware – Cost, Complexity • Cable Grade – Cladding or Sheath Material, Fire Codes, Usable in walls or plenum. • Bend Radius – Degrees per feet • Material Cost • Installation Cost
Boadband and Baseband Communication • Baseband • Uses a single frequency to transmit digital pulses. • Half Duplex per strand (2 strands for Full Duplex). • Bi-directional – one strand can be used for sending and receiving. • Repeaters and switches are used for signal regeneration. • Used in Ethernet • Broadband • Analog Transmission • More than one frequency can be on one strand • A single strand can support Full Duplex • One frequency is unidirectional – 2 strands (Dual-Cable Broadband) or 2 frequencies (Mid-split broadband) needed for Full Duplex. • Amplifiers used to strengthen signals.
Cable Types - Coax • Used by Cable TV • No longer used in LANs • Interference: better than twisted pair, worse than fiber • Used in early Ethernet Applications • 10Base5 (10 Mbps, Baseband, 500 meter segments) - Thicknet • 10Base2 (10 Mbps, Baseband, 200 meter segments) - Thinnet • Used in Physical Bus Ethernet networks • Cable Modem Applications • 75 ohm, RG-6 (Radio Grade) • 256 Kps up to 1 Mbps • Shared resource: more connections = lower bandwidth
Coaxial Cable in Cable Modem Applications (continued)Tomsho, Tittel, Johnson (2007)
Cable Types – Twisted Pair • Twisted Pair (TP) – strand pairs are twisted around each other – minimizes interference and crosstalk. • Unshielded Twisted Pair (UTP) • Ethernet: 10BaseT (10 Mbps, Basedband, UTP) – requires physical Star topology (Odom, 2006) • UTP most popular LAN cable • Also used in Phone Systems
Cable Types – Twisted Pair • Shielded Twisted Pair (STP) – similar to UTP, except that braided pair is contained in a foil. • No standard exists for STP. • UTP and STP usually use RJ-45 (Registered Jack) telephone connectors. • RJ-45 contain 8 contacts, although, only 4 are used, 2 for transmit (+/-) and 2 for receive (+/-) • 2 different standards for wiring an RJ-45 connector: TIA/EIA 58A and TIA/EIA 58B • Cable Wiring Strategies (Odom, 2006) • Straight Through Wiring: • Pins (1,2) -> Pins (1,2) and Pins (3,6) -> Pins (3,6) • Used for connecting PC’s to hubs or switches • Crossover Wiring: • Pins (1,2) -> Pins (3,6) and Pins (3,6) -> Pins (1,2) • Used for connecting PC’s to PC’s or switches to switches
Twisted-Pair Cable (continued)Tomsho, Tittel, Johnson (2007)
Cable Types – Fiber Optic • Uses light rather than EM signals to transmit information. • Not susceptible to EMI or RFI • Does not broadcast or radiate EM signals • Extremely secure to electronic eavesdropping. • Very High Bandwidth: 10 Gb/s and greater • Maximum cable segments on the order of miles. • More fragile, less flexible than copper. • More expensive. • Each strand passes signals in one direction.
Single and Multi-Mode Fiber • Information on this slide comes from (Odom, 2006) • Multi-Mode: • Used with LEDs • LEDs spread light in multiple angles • LED light doesn’t travel as far as laser • Thicker core to absorb angular LED light • Single-Mode • Used with Lasers • Lasers don’t spread light – single direction • Thinner core • Laser light travels further than with LED source
Cable Type Comparisons • Comparison of cost and performance of different cable types (Tomsho, 2007)
Cable Considerations • Plan network to separate light/moderate users from heavy users. • Plan network to separate local traffic from backbone traffic • A mixture of TP connected by hubs which are then interconnected by coax or fiber give TP greater reach • Need to consider existing cable plant.
Structured Cabling • Defines cable plant organization (TIA/EIA 568) • Work Area work station environment, patch cables (<6 meters). • Horizontal Wiring cabling from work area to Telecommunications Closet (<90 meters) • Telecommunications Closet (TCs) patch panel, hubs, switches. • Equipment Rooms servers, switches, routers • Backbone Cabling that connects equipment rooms, TCs. Fiber often used. • Entrance Facilities location where leased lines meet Enterprise network.
Wireless LANs (WLAN) • Standards are defined by Institute of Electrical and Electronics Engineers (IEEE) • IEEE 802.11 networking characteristics is similar to Ethernet (IEEE 802.3) • Characteristics of 802.11(IEEE 802.11, n.d.)
The Wireless World (continued)Tomsho, Tittel, Johnson (2007)
Wireless MAN: The 802.16 StandardTomsho, Tittel, Johnson (2007) • One of the latest wireless standards, 802.16 Worldwide Interoperability for Microwave Access (WiMax), comes in two flavors: 802.16-2004 (previously named 802.16a), or fixed WiMax, and 802.16e, or mobile WiMax • Promise wireless broadband to outlying and rural areas, where last-mile wired connections are too expensive or impractical because of rough terrain • Delivers up to 70 Mbps of bandwidth at distances up to 30 miles • Operates in a wide frequency range (2 to 66 GHz)
References Tomsho, Tittel, Johnson (2007). Guide to Networking Essentials. Boston: Thompson Course Technology. Odom, Knott (2006). Networking Basics: CCNA 1 Companion Guide. Indianapolis: Cisco Press Wikipedia (n.d.). IEEE 802.11. Retrieved 09/10/2006 from http://en.wikipedia.org/wiki/802.11a Wikipedia (n.d.). OSI Model. Retrieved 09/12/2006 from http://en.wikipedia.org/wiki/OSI_Model