Lecture-3 ISO Model, Network Security, and Protocols

The most common causes of network lecture 3 33

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Unformatted text preview: i.e., violations of availability) Communications and Network Security …cont. Coaxial Cable: Also called coax, was a popular networking cable type used throughout the1970s and 1980s. In1990s, its use quickly declined due to the popularity of twisted pair wiring. Coaxial cable has a center core of copper wire surrounded by a layer of insulation, which is in turn surrounded by a conductive braided shielding and Lecture-3 34 encased in a final insulation sheath. Communications and Network Security …cont. The most common problems with coax cable are as follows: Bending the coax cable past its maximum arc radius and thus breaking the center conductor Deploying the coax cable in a length greater than its maximum recommended length (e.g.,185 m for 10Base2 or 500 m for 10Base5) Not properly terminating the ends of the Lecture-3 35 coax cable with a 50 ohm resistor. Communications and Network Security …cont. Baseband and Broadband: XXyyyyZZ. XX represents the maximum speed the cable type offers, such as 10Mbps for a 10Base2 cable. yyyy represents the baseband or broadband aspect of the cable, such as baseband for a 10Base2 cable. Baseband cables can transmit only a single signal at a time. Broadband cables can transmit multiple signals simultaneously. Most networking cables are baseband cables. However, when used in specific configurations, coaxial cable can be used as a broadband connection, such as with cable modems. ZZ either represents the maximum distance the cable can be used or acts as shorthand to represent the technology of the cable, such as the approximately 200 meters for 10Base2 cable (actually 185 meters, but it’s rounded up to 200), or T or TX for twisted-pair in 10Base-T or 100Base-TX. (Note that 100Base-TX is implemented using two CAT 5 UTP or STP cables, one issued for receiving, the other for transmitting.) Lecture-3 36 Communications and Network Security …cont. Lecture-3 37 Communications and Network Security …cont. Twisted-Pair: Twisted-pair cabling is extremely thin and flexible...
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This note was uploaded on 01/21/2014 for the course IT 205 taught by Professor Kurts during the Winter '08 term at University of Phoenix.

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