98-366 Unit 3 Understanding Wired And Wireless Networks (3)

UTP Unshielded twisted-pair (UTP) is the cable most commonly used in local area networks. It's relatively easy to work with, flexible, efficient, and fast.

568B Crossover cable is used to connect like devices to each other—for example, a computer to another computer, or a switch to another switch. With the crossover cable, the patch cable is wired with the 568B standard on one side and the 568A standard on the other.

crossover cable A crossover cable is used to connect like devices to directly each other.

punch-down tool The tools necessary to make the connections between patch panels and RJ45 jacks include a cutting tool, a wire stripper, a punch-down tool, and a continuity tester.

Category 5 Twisted-pair cables are categorized according to the frequency at which they transmit signals and their data transfer rate or speed. To support 100 Mbps, you need to use a minimum of category 5. The maximum length is 100 m.

RFI Wireless adapters/networks use 2.4 or 5.0 GHz, which is the same frequency that wireless phones use. Therefore, if both operate at the same time, you have radio frequency interference (RFI).

fiber A common type of interference is crosstalk, in which the signal that is transmitted on one copper wire or pair of wires creates an undesired effect on another wire or pair of wires.

plenum-rated Cables that are 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.

crosstalk A common type of interference is crosstalk, in which the signal that is transmitted on one copper wire or pair of wires creates an undesired effect on another wire or pair of wires.

RJ-45 Fiber connectors include FC, LC, MT-RJ, SC, and ST. RJ-45 is used for UTP cables.

Single-mode fiber supports longer distances than multimode fiber. With single-mode fiber, you send one signal. As a result, the single mode can communicate over multi-mode.

11 Mbps :: 802.11b runs at 2.4 GHz and supports up to 11 Mbps.

54 Mbps 802.11g runs at 2.4 GHz and supports up to 54 Mbp

RFI protection 802.11n is superior to older WLAN standards in the following ways: Multiple-Input Multiple-Output (MIMO), frame aggregation, and channel bonding.

WPA2 Several types of encryption are available for wireless networks, but the most secure is WPA2 when used with AES.

SSID When utilizing infrastructure mode, the base unit (normally a WAP) will be configured with a service set identifier (SSI. This then becomes the name of the wireless network and it is broadcast over the airwaves. Thus, when clients want to connect to the WAP, they can identify it by the SSID.

continuity tester To make the connections between patch panels and RJ45 jacks you need a cutting tool, a wire stripper, a punch-down tool, and a testing device known as a continuity tester, which tests all connection pins one by one.

802.1X One way to secure a wireless connection is to use IEEE 802.1X,a port-based network access control (PNA. This provides strong authentication to devices that need to connect to the WLAN; it can also be used for regular wired LANs.

attenuation Generally, you can run twisted-pair cables 100 meters before the signal degrades to such a point that it cannot be interpreted by the destination host. This is known as attenuation. If a cable needs to be run farther, you can use a signal repeater, a hub, or switch. Otherwise, fiber-optic cable is the solution because you can run it much farther than twisted-pair cable.

infrastructure mode Infrastructure mode occurs when wireless clients connect to and are authenticated by a wireless access point, which can be expanded by creating a wireless distribution system—a group of WAPs interconnected wirelessly.