12135719
Description
Flashcards by Tim Bowater, updated more than 1 year ago
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Created by Tim Bowater
about 6 years ago
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| Question | Answer |
| Twisted-Pair Cable | " The most commonly used cable type in local area networks. Relatively easy to work with, flexible, efficient and fast. Contains eight wires grouped into four twisted pairs, typically blue, orange, green, and brown. The twisted wires reduce crosstalk and interference |
| Category 3 (Cat-3) | 10 Mbps |
| Category 5 (Cat-5) | 100 Mbps |
| Category 5e (Cat-5e) | 100 Mbps and 1000 Mbps+ |
| Category 6 (Cat-6) | 1000 Mbps+ |
| Types of Patch Cables | Straight through cable o Most common type of patch cable. o Used to connect a computer to a central connecting device like a switch. Crossover cable o Used to direct connect similar devices without the use of a hub. E.g. Computer to computer. When you build a crossover cables, the ends are opposite. E.g. Computer to computer. |
| MDI and MDI-X Ports | Medium dependant interface (MDI) is a type of Ethernet port connection using twisted pair cabling For computers to communicate with other devices, the wires have to cross somewhere. |
| MDI and MDI-X Ports | Instead of using crossover cables to connect to computers to central connecting devices such as switches, these central connecting devices are equipped with MDI-X ports (medium dependent interface crossover), which take care of the cross. Most switches these days have auto sensing ports so they know what type of cables you are plugging in |
| Attenuation | Measured in decibels (dB). According to the IEEE 802.3 standard, twisted-pair cables can be run 100 meters. Beyond this the signal degrades to such a point that it cannot be interpreted by the destination host. A signal repeater, a hub, or switch can be used if a cable needs to be run farther. |
| Interference | Electrical Sources o Lights o Electrical Outlets o Motors o Applications Copper-based cables and network devices should be kept away from these electrical devices and cables if at all possible. Examples of wireless interference are walls, microwaves etc. Elevators. |
| Electromagnetic Interference (Emi) | Electromagnetic Interference (EMI) disturbance can affect electrical circuits, devices, and cables due to electromagnetic conduction and possibly radiation. Any type of electrical device causes EMI: TVs, air conditioning units, motors, unshielded electrical cables (Romex). Copper-based cables and network devices should be kept away from these electrical devices and cables to prevent network communication issues. |
| Radio Frequency Interference (RFI) | This is interference that can come from AM/FM transmissions and cell phone towers. It is often considered part of the EMI family and is sometimes even referred to as EMI. Filters can be installed on the network to eliminate the signal frequency being broadcast by a radio tower, although this will usually not affect standard wired Ethernet networks. |
| Crosstalk | When it comes to twisted-pair cabling, crosstalk is broken down into two categories: o Near end crosstalk (NEXT) occurs when there is measured interference between two pairs in a single cable, measured on the cable end nearest the transmitter. o Far end crosstalk (FEXT) occurs when there is similar interference, measured at the cable end farthest from the transmitter. |
| Shielded Twisted-Pair (STP) Cables | Shielded Twisted-pair (STP) Cables STP cables have an aluminum shield inside the plastic jacket that surrounds the pairs of wires. |
| Plenum-Rated | Cables installed inside walls or above drop ceilings where they cannot be accessed by sprinkler systems in the case of a fire should be plenum-rated or low-smoke rated. Plenum-rated cables have a Teflon coating that makes them more impervious to fire. They are used in these situations because standard twisted-pair cables have a PVC jacket, which can emit deadly gas into the air. |
| Fiber Optic Cable | Very good for high-speed, high-capacity data transmission due to lack of attenuation. Single-mode o Meant to carry a single ray of light - one ray of light, one mode. o This type of cable is normally used for higher-bandwidth, longer-distance, generally 10-80km. o More expensive equipment. |
| Fiber Optic Cable | Multi-mode o Cable with a larger fiber core, capable of carrying multiple rays of light. o This type of cable is used for shorter distances runs, up to 600 meters. o Though much shorter than single mode fiber runs, this is still six times the distance of twisted-pair cable runs. o Less expensive equipment. Used for the backbone of the network. |
| Wireless Networks | Enables connection to the network without using a wired connection. Provide a degree of portability. Extend connectivity to a pre-existing wireless network and could be used to connect entire local area networks to the internet. Some wireless devices can be connected directly to each other in a point-to-point fashion. |
| Wireless Network Adapters | Wireless network adapters enable connectivity between a desktop computer or laptop and the wireless access point. These network adapters come in a variety of shapes and sizes, including USB, PC CARD, and as an internal PCI or PCI Express adapter card. |
| Wireless Access Point | A Wireless Access Point (WAP) enables wireless devices to connect to a wired network. A wireless router can also act as a router, firewall, and IP proxy |
| Wireless Modes | There several different methods to connect to a wireless network. o Infrastructure - the mode used when wireless clients connect to and are authenticated by a wireless access point. o Ad-hoc - used when all of the clients communicate directly with each other. |
| Wireless LAN (WLAN) | Wireless LAN or WLAN is a network composed of at least one WAP and a computer or handheld device that connect to the WAP. Usually these networks are Ethernet based, but they can be built on other networking architectures. |
| Wireless LAN (WLAN) | In order to ensure compatibility, the WAP and other wireless devices must all use the same IEEE 802.11 WLAN standard. Wireless Fidelity (Wifi) is a trademark to brand products that belong to the category of WLAN devices. |
| Other wireless devices | Wireless Repeater o. Used to extend the coverage of a wireless network Wireless Bridge o A wireless bridge is similar to a wireless repeater, but the bridge can connect different 802.11 standards together; this is known as bridge mode. E.g. 802.11a/b/g/n etc. |
| WEP | Wired Equivalent Privacy 64-bit |
| WPA & WPA2 | Wi-Fi Protected Access 256-bit |
| TKIP | Temporal Key Integrity Protocol 128 bit |
| AES | Advanced Encryption Standard 128-, 192- and 256-bit |
| Service Set Identifier (SSI) | " When utilizing infrastructure more, the base unit (normally a WAP) will be configured with a service set identifier (SSID). The SSID is the name of the wireless network, and it is broadcast over the airwaves. When clients want to connect to the WAP, they can identify it by the SSID. For security, the SSID can be hidden from public discovery. |
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