Читать книгу Networking All-in-One For Dummies - Lowe Doug, Doug Lowe - Страница 136

The names of Ethernet cable standards resemble the audible signals a quarterback might shout at the line of scrimmage. In reality, the cable designations consist of three parts:

 The first number is the speed of the network in Mbps. So, 10BaseT is for 10 Mbps networks (Standard Ethernet), 100BaseTX is for 100 Mbps networks (Fast Ethernet), and 1000BaseT is for 1,000 Mbps networks (Gigabit Ethernet).

 “Base” (short for “baseband”) indicates the type of network transmission that the cable uses. Baseband transmissions carry one signal at a time and are relatively simple to implement. The alternative to baseband is broadband, which can carry more than one signal at a time but is more difficult to implement. At one time, broadband incarnations of the 802.x networking standards existed, but they have all but fizzled due to lack of use.

 The tail end of the designation indicates the cable type. For coaxial cables, a number is used that roughly indicates the maximum length of the cable in hundreds of meters. 10Base5 cables can run up to 500 meters. 10Base2 cables can run up to 185 meters. (The IEEE rounded 185 up to 200 to come up with the name 10Base2.) If the designation ends with a T, twisted-pair cable is used. Other letters are used for other types of cables.

In the following sections, I point out a few more details of the three most important protocols in the TCP/IP suite: IP, TCP, and UDP.