Networking Technologies

Cabling

Ethernet Cabling A network's cabling, or transmission media, provides the physical path that data travels in a network. An Ethernet network is connected using one of several types of cable. The cable is categorized by its bandwidth, or capacity. Bandwidth is the range of cycle frequencies, measured in Hz, that the cable can accommodate. An Ethernet network in usually comprised of thick coaxial cable (Thicknet), thin coaxial cable (Thinnet), or twisted-pair (UTP) cable.

Thicknet

Thicknet cable is composed of thick coaxial cable. Coaxial cable is composed of two conductors that share a common axis. The center of the cable has an insulated copper wire. The second conductor, a wire mesh tube or conductive foil wrap, surrounds the copper wire. The cable is encased in a tough, insulated plastic tube. Thicknet cable is also known as 10BASE5. "10" represents the data rate in megabits per second (Mbps). "BROAD" refers to broadband signals. "5" is the approximate distance (x 100) that data can travel. Thicknet is stiff and inflexible. Therefore, making changes or additions to a Thicknet network is difficult.

Thin Coaxial

Thin coaxial cable (10BASE2) is used in a bus topography, as is Thicknet. Using a bus topography, each computer is connected to a single cable that passes each computer. Computers connect to this cable using a "T" shaped connector. Thin coaxial cable can be damaged from twisting and bending. As with Thicknet, adding or changing devices to a 10BASE2 network can be challenging. Thin coaxial cable is the least expensive type of cabling to implement.

Unshielded Twisted Pair

Unshielded Twisted-pair cabling (10BASE-T) is the most common type of transmission media used in an Ethernet network. It is also used as telephone cable. It is composed of 4 pairs of twisted wire sheathed in plastic. There are 5 different qualities of twisted pair cable: Category 1 and 2: voice-grade and low-speed data (<4 Mbps) Category 3: data (10-16 Mbps) Category 4: data (<20 Mbps) Category 5: high-speed data (<100Mbps) Unshielded Twisted-pair cable is very inexpensive compared to other types of transmission media. UTP installation equipment is inexpensive and easy to use. Because telecommunication systems use UTP and their connection techniques are optimized for easy reconfiguration, computer networks using UTP can also be easily managed and reconfigured.

Fast Ethernet

There is another implementation of Ethernet known as Fast Ethernet (10BASE-TX). The data transfer rate is 100 (100Mbps) or 10 times faster than a traditional Ethernet network. 10BASE-TX uses two pairs of Category 5 UTP cabling. 100BASE-T4 uses four pairs of Category 3, 4, or 5 UTP. 100BASE-FX uses two-strand multi-mode or single-mode fiber optic cable. Fiber optic cable is made of a light conducting glass or plastic core surrounded by more glass covered by a hard plastic encasement. Optical fibers are smaller and lighter than copper wires and can carry more conductors. Single-mode fiber allows only one light path, while multi-mode fiber allows various light paths. Single-mode fiber has a higher bandwidth, but is more expensive to produce than multi-mode fiber.

Other Sources

For more information about Ethernet cabling, visit these sites:

comp.dcom.cabling newsgroup FAQ

Introduction to 10Base-T Ethernet by Nathan J. Muller

Charles Spurgeon's Ethernet Web Site