1 / 43

Network Connectivity (Topic 2)

Network Connectivity (Topic 2). Textbook: Networking Basics, CCNA 1 Companion Guide , Cisco Press Cisco Networking Academy Program, CCNA 1 and 2, Companion Guide , Cisco Press, Latest Edition. Analog Signal Vs Digital Signal. Analog data is continuous data

ariel-gross
Télécharger la présentation

Network Connectivity (Topic 2)

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. Network Connectivity(Topic 2) Textbook: Networking Basics, CCNA 1 Companion Guide, Cisco Press Cisco Networking Academy Program, CCNA 1 and 2, Companion Guide, Cisco Press, Latest Edition CIM 2465 Network Connectivity

  2. Analog Signal Vs Digital Signal • Analog data is continuous data • The world we live in is mainly an analog world. E.g. light, video, voice • Digital data is discrete, values are distinct from one another. • Digital computers process data in digital form (0 or 1) • A/D D/A conversion (e.g. modem) CIM 2465 Network Connectivity

  3. Analog Signal Vs Digital Signal CIM 2465 Network Connectivity

  4. Properties of an Analog Signal • Amplitude • Frequency • Phase • Modulation and Demondulation CIM 2465 Network Connectivity

  5. Factors AffectingTransmission of Signals • Noise • Refers to any interference on the physical medium that makes it difficult for the receiver to detect the data signal • Crosstalk • Noise created on one wire as a result of current flowing over a nearby wire • Attenuation • Attenuation in an electrical signal is a decrease in voltage as the signal crosses the wire • Can be caused by • Resistance of wires • Energy loss • Frequency of signal CIM 2465 Network Connectivity

  6. CIM 2465 Network Connectivity

  7. Digital Transmission • Digital Transmission is a general term that refers to how computing devices transmit the binary bits from one to another • Can be done by (Modulation) • Varying (modulating) an electrical signal as it passes over a copper wire • Varying the power of light as sent over an optical fiber • Varying the radio waves sent through space, wireless communications CIM 2465 Network Connectivity

  8. Transmission Media • Major types • Copper Wires • Coaxial Cable, Shielded Twisted Pair (STP), Unshielded Twisted Pair (UTP) • Optical • Wireless • Considerations • Transmission speed • Digital or Analog transmission • Transmission distance CIM 2465 Network Connectivity

  9. Coaxial Cable • Composed of a single copper wire, surrounded by an insulating shell, then a second conductor shield, and a plastic outer shell • Types: • Thick Coaxial (10Base5) • Thin Coaxial (10Base2) • Today’s modern LANs no longer use 10BASE5 and 10BASE2 CIM 2465 Network Connectivity

  10. Coaxial Cable • Advantages • Longer transmission distance than STP and UTP, fewer repeaters needed • Less expensive than fiber-optic, more expensive than STP and UTP • High bandwidth medium that can carry thousands of signals, support broadband transmission of cable TV, a single cable is divided into many channels for transmission. Commonly used to deliver cable-television signals and high-speed Internet access CIM 2465 Network Connectivity

  11. Coaxial Cable CIM 2465 Network Connectivity

  12. Twisted Pair Wire • Most commonly used data transmission medium • Its core consists of pairs of copper wires twisted together to create magnetic field and thus reduce interference • 2 types: • Shielded Twisted Pair (STP) • Unshielded Twisted Pair (UTP) CIM 2465 Network Connectivity

  13. Shielded Twisted Pair (STP) CIM 2465 Network Connectivity

  14. Shielded Twisted Pair (STP) • Shielding provides a cleaner electrical current by reducing attenuation and noise, thus longer cabling lengths • More expensive, heavier, and difficult to bend when installing them (compare with UTP) CIM 2465 Network Connectivity

  15. Unshielded Twisted Pair (UTP) • Grouped into categories based on quality • Generally used in LAN • Cat 5 cable • RJ45 connector CIM 2465 Network Connectivity

  16. Unshielded Twisted Pair (UTP) • Adv • Does not require grounding like STP, easier to add connectors • Thinner, more flexible to install • Same data speeds as other copper media • Disadv • More susceptible to electrical noise and interference • Shorter cabling distance (100m when used for Ethernet LANs) CIM 2465 Network Connectivity

  17. Twisted Pair Wire • Advantages • Commonly available and relative low cost, especially where telephone lines have already been installed • Disadvantages • Subject to signal distortion, noise and interference, and the relatively low transmission rates CIM 2465 Network Connectivity

  18. Fiber Optic Cable • Thin wire (usually very pure glass or plastic) surrounded by a reflective cladding that is used to transmit optical signals (light) • Copper wire cables transmit signals electrically, whereas fiber-optic cables transmit signals by means of light • More expensive than copper wires, more skill to install CIM 2465 Network Connectivity

  19. Fiber Optic Cable CIM 2465 Network Connectivity

  20. Fiber Optic Cable • Not susceptible to lightning, electromagnetic interference (EMI), or radio frequency interference (RFI), and does not generate EMI or RFI • Much greater bandwidth • Greater transmission distances • Excellent signal quality CIM 2465 Network Connectivity

  21. Fiber Optic Cable • More secure (difficult to tap) • Thin, requires little space in a conduit • Lightweight, easy to install • Better resistance to environment factors, e.g. water • Generally used to link LANs, WANs, or as backbone of large networks CIM 2465 Network Connectivity

  22. Fiber Optic Cable • Fiber Optics Types: • Multi-mode cable • Less expensive • Less expensive LED transmitters are used • Larger core, multiple angles of entry • Single-mode cable • More expensive • More expensive laser transmitters are used • Significant longer cabling distances • Skinny core, only one angle of entry CIM 2465 Network Connectivity

  23. Fiber Optic Cable CIM 2465 Network Connectivity

  24. Wireless Media (1) • Infrared • Radio wave • Bluetooth • Wifi • Mobile Phone network (e.g. GSM, 3G) • Microwave • Satellite CIM 2465 Network Connectivity

  25. Wireless Media (2) • WLAN Components • PCs with WLAN NICs • Access Points (APs), which act as a LAN hub for wireless devices • Infrastructure mode • Uses APs, with the PCs sending and receiving data to and from the AP • Ad-hoc mode • Formed by any two wireless devices, find and associate with each other CIM 2465 Network Connectivity

  26. Wireless Media (3) • To install a WLAN that works with the existing LAN infrastructure • At least one AP • A straight-through cable to connect AP to an existing LAN switch • Wireless NICs in end-user devices to communicate with the APs CIM 2465 Network Connectivity

  27. CIM 2465 Network Connectivity

  28. Wireless Media (4) • WLAN Organization and Standards • IEEE defines WLAN standards 802.11 • Wi-Fi alliance (www.wi-fi.org) CIM 2465 Network Connectivity

  29. LAN Cabling • Considerations • Ethernet Types • Media • Speed • Distance • Connector CIM 2465 Network Connectivity

  30. LAN UTP Cabling Standards CIM 2465 Network Connectivity

  31. Ethernet LAN Media and Connectors CIM 2465 Network Connectivity

  32. UTP Cable Pinouts • Key concepts • Ethernet devices (at 10 and 100Mbps Ethenet) use one pair of wires to transmit data • Ethernet devices (at 10 and 100Mbps Ethenet) use another pair of wires to receive data • Two pairs of wires are required • Types • Straight-Through Cable • Crossover Cable • Console Connection and Rollover Cable CIM 2465 Network Connectivity

  33. Straight-Through Cable • To connect an end-user device and a LAN hub or switch • PC’s NIC uses • Pin 1, 2 to transmit • Pin 3, 6 to receive • LAN hubs, switches (the other end) • Pin 3, 6 to transmit • Pin 1, 2 to receive CIM 2465 Network Connectivity

  34. Straight-Through Cable • TIA/EIA-T568-B or A on BOTH ends of the cable CIM 2465 Network Connectivity

  35. TIA/EIA 568-A CIM 2465 Network Connectivity

  36. Crossover Cable • To connect two devices that both want to send on the same pins (two devices of similar ‘type’, e.g. two PCs) • BOTH sides use • Pin 1, 2 to transmit • Pin 3, 6 to receive CIM 2465 Network Connectivity

  37. Crossover Cable • One side is T568-A and T568-B one the other (10BaseT, 100BaseT) • Special arrangement for 1000BaseT CIM 2465 Network Connectivity

  38. How to choose? • Two groups of devices • PC, router, server, AP (use pins 1 and 2 to transmit) • Switch, hub, bridge, repeater (use pins 3 and 6 to transmit) • When connecting two devices that are similar in regard to which pins they use to transmit, use a crossover cable • e.g. Switch to Switch, Switch to Hub, Hub to Hub, Router to Router, PC to PC, Router to PC • When connecting two devices that differ in regard to which pins they use to transmit, use a straight-through cable • e.g Switch to Router, Switch to PC, Hub to PC CIM 2465 Network Connectivity

  39. CIM 2465 Network Connectivity

  40. Basic Models for PC Communications (1) • Peer-to-peer • A computer acts as a peer with other computer by acting both as a client and a server • E.g. Sharing a folder in a Windows workgroup • Adv • Simple to install • No special hardware required • Most OS support peer-to-peer networking • No network administrators required • Disadv • Security • Loss control CIM 2465 Network Connectivity

  41. Basic Models for PC Communications (2) • Client/Server • A computer acts as either a client or a server • Server usually is more powerful, and requires a more expensive network operating system (NOS) • Adv • Centralized control • Security control • Easier data backup • Disadv • Cost • Network administrators required • If server fails, …. CIM 2465 Network Connectivity

  42. CIM 2465 Network Connectivity

  43. Comparing Peer-to-Peer and Client/Server CIM 2465 Network Connectivity

More Related