CertiGuide to Network+  9  Chapter 0001:  LAN Cabling       9  VI  Twisted Pair cabling standards

VGAnyLan 1 2 Troubleshooting 10nBaseTx

The 1000BaseTX (sometimes called just 1000BaseT) standard is the next level of 10xBase-T networking. Just as Fast Ethernet is 10 times as fast as the 10BaseT standard, 1000BaseT (or Gigabit Ethernet) is 10 times as fast as the 100BaseT standard. It is called Gigabit Ethernet to denote that its data transmission speed is 1 gigabit (1000 megabits) of data per second. Contrast this with Fast Ethernet, which can transmit 100 megabits of data per second.

Unlike VGAnyLan, it uses the same Ethernet CSMA/CD technology that is used by its older relatives, 10BaseT and 100BaseT.

Its advantage over those technologies is its speed. An additional advantage is that it can sometimes be run over a site’s existing Cat 5 cable, if certain networking hardware, designed specially to run gigabit Ethernet over Cat 5 cable, is used.

The first question that may come to mind is “how did the engineers increase the speed a ten fold over Fast Ethernet?” The answer lies in several changes. Ethernet and Fast Ethernet both use 2 pairs of copper. Gigabit Ethernet uses 4 pairs.

Another change is the number of encoded channels for data. Previous to Gigabit Ethernet, data was encoded to three different levels or channels. With Gigabit Ethernet, a total of 5 different channels are used on each pair. That translates to a total of 20 channels of encoded information on Gigabit Ethernet, versus 6 in the previous offerings.

If the above information is not enough reason to consider the move to Gigabit Ethernet, consider one more change. Ethernet and Fast Ethernet both use Error Detection for badly formed signals. Gigabit Ethernet uses Error Detection and Correction. Consider the ramifications of the differences. In the two previous versions of Ethernet, if a piece of data was found to be bad, the data is re-sent. In Gigabit Ethernet, the error has a chance to be corrected, without bandwidth-consuming retransmission of the data.

VGAnyLan 1 2 Troubleshooting 10nBaseTx