1 / 86

Media, Connections & Collisions – 1

Media, Connections & Collisions – 1. Andres, Wen-Yuan Liao Department of Computer Science and Engineering De Lin Institute of Technology andres@dlit.edu.tw http://www.cse.dlit.edu.tw/~andres. Overview. Defines the electrical, mechanical, procedural, and functional specifications

lara
Download Presentation

Media, Connections & Collisions – 1

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Media, Connections &Collisions – 1 Andres, Wen-Yuan Liao Department of Computer Science and Engineering De Lin Institute of Technology andres@dlit.edu.tw http://www.cse.dlit.edu.tw/~andres

  2. Overview • Defines the electrical, mechanical, procedural, and functional specifications • Networking media • Network devices, cable specifications, network topologies, collisions and collision domains

  3. Most Common LAN Media • STP and ScTP • UTP • Coaxial cable • Optical fiber • Wireless communication

  4. STP • The techniques of shielding, cancellation, and twisting of wires • Each pair of wires is wrapped in metallic foil • The 4 pairs of wires are wrapped in an overall metallic braid or foil. • 150 Ohm cable

  5. STP • STP reduces electrical noise • Within the cable: crosstalk • From outside the cable: EMI and RFI • Greater protection from all types of external interference • More expensive • Difficult to install

  6. ScTP • A new hybrid of UTP with traditional STP • Foil Twisted Pair (FTP) • Essentially UTP wrapped in a metallic foil shield, or "screen“ • 100 or 120 Ohm cable

  7. STP & ScTP • Works both ways (inside, outside) • Need to be grounded at both ends • Increase the size, weight, and cost of the cable • Shielding materials make terminations more difficult

  8. UTP • Unshielded twisted-pair cable • A four-pair wire medium • Each pair of wires are twisted around each other • Limit signal degradation caused by EMI and RFI

  9. UTP • 22 or 24 gauge copper wire • 100 ohms • External diameter of approximately .43 cm • Most of the major networking architectures

  10. UTP • Advantages • Easy to install • Costs less • Small external diameter • Disadvantages • More prone to electrical noise and interference • Distance between signal boosts is shorter

  11. Coaxial cable • Consists of a hollow outer cylindrical conductor that surrounds a single inner wire • Advantages • Longer distances • Less expensive than fiber-optic cable • The technology is well known

  12. Coaxial Cable • Thicknet:largest diameter • Ethernet backbone cable • More expensive to install • Thinnet: cheapernet • An outside diameter of only .35 cm • Useful for cable installations • Taken to ensure that it is properly grounded

  13. Optical fiber • A networking medium capable of conducting modulated light transmissions • More expensive • Is not susceptible to electromagnetic interference • Is capable of higher data rates

  14. Optical Fiber • The light-guiding parts: the core and the cladding • The core: very pure glass • High index of refraction • Is surrounded by a cladding layer • A cladding layer: glass or plastic • Low index of refraction

  15. Wireless communication • Wireless signals are electromagnetic waves • Travel through the vacuum of outer space and through media such as air • No physical medium is necessary

  16. The speed of light, c = 299, 792, 458 meters per second • (frequency) x (wavelength) = c • The primary difference between the different electromagnetic waves is their frequency

  17. Application of wireless • Mobile use • WLAN: Wireless LANs • The IEEE 802.11 standards • Radio waves (for example, 902 MHz), microwaves (for example, 2.4 GHz), and Infrared waves (for example, 820 nanometers) for communication

  18. Cable Specification and Termination • Purpose of LAN media specifications • TIA/EIA standards • Explain the details of TIA/EIA-568-A • Networking media and terminations

  19. Purpose of LAN media specifications • Work compatibly and interoperably • IEEE - Institute of Electrical and Electronics Engineers • UL - Underwriters Laboratories • EIA/TIA • EIA - Electronic Industries Alliance • TIA - Telecommunications Industry Association

  20. IEEE • Has outlined cabling requirements • 802.3 and 802.5 specifications for Ethernet and Token Ring systems • The standards for FDDI

  21. Underwriters Laboratories • Issues cabling specifications that are primarily concerned with safety standards

  22. TIA/EIA standards • The greatest impact on networking media standards • Specify the minimumrequirements for multi-product and multi-vendor environments • TIA/EIA-568-A and TIA/EIA-569-A • The most widely used standards for technical performance of networking media

  23. Details of TIA/EIA-568-A • Six elements of the LAN cabling process • Horizontal cabling • Telecommunications closets • Backbone cabling • Equipment rooms • Work areas • Entrance facilities

  24. Horizontal Cabling • Cabling that runs from a telecommunications outlet to a horizontal cross-connect • Networking media • The maximum distance for cable runs in horizontal cabling is90 meters (m)

  25. Two Telecom Outlets • The first is a four-pair 100 ohm CAT 3 or higher UTP cable • The second can be any one of the following: • Four-pair 100 ohm UTP • 150 ohm STP • Coaxial cable • Two-fiber 62.5/125 µ optical fiber cable

  26. Networking Media • Shielded twisted-pair • Two pair 150 ohm cable • Unshielded twisted-pair • four pair 100 ohm cable • Fiber-optic cable • two fibers of 62.5/125 multi-mode cable • Coaxial cable • 50 ohm coaxial cable

More Related