Cabling, Lines, and Services

Bandwidth

The total amount of information that can traverse a communications medium measured in millions of bits per second. Bandwidth is helpful for network per¬formance analysis. Also, availability is increasing but limited.

Crosstalk

An electrical or magnetic field that is a result of one communications signal that can affect the signal in a nearby circuit.

Near-end Crosstalk (NEXT)

Crosstalk measured at the transmitting end of a cable.

Far-end Crosstalk (FEXT)

Crosstalk measured at the far end of the cable from where the transmission was sent.

Unshielded twisted-pair (UTP) cables are vulnerable to Electromagnetic Interference (EMI) and use an RJ-45 connector. Fiber-optic cables are not susceptible to EMI.

Use a straight-through cable to connect the following devices:

.      Terminated directly into a dedicated hub or switch port

.      From a PC to a switch or a hub

.      From a router to a switch or a hub

Use a cross-over cable to connect the following devices:

.      From switch to switch

.      From router to router

.      From PC to PC

.      From a PC to a router

.      From a hub to a hub

.      From a hub to a switch

Spread Spectrum Wireless LANs allow for high-speed transmissions over short distances.

Wireless Fidelity (Wi-Fi) is defined by IEEE 802.11.