1000BASE-T — an Essential Technology in Gigabit Ethernet
1000BASE-T, also known as IEEE 802.3ab, is a type of standard for implementing Gigabit Ethernet networks. In 1000BASE-T, the “1000” refers to the transmission speed of 1000 Mbps, the “BASE” refers to baseband signalling and the “T” is an extension of the traditional 10BASE-T and 100BASE-T Ethernet technologies for transmission over copper unshielded twisted-pair (UTP) cabling. Among the various standards for Gigabit Ethernet over copper wiring, 1000BASE-T provides half-duplex (CSMA/CD) and full-duplex 1000Mb/s Ethernet service over Category 5 links as defined by ANSI/TIA/EIA-568-A. The 1000BASE-T technology is in the beginning stages of being widely implemented in enterprise-level networks.
Why 1000BASE-T is an Essential Technology in Gigabit Ethernet
Gigabit Ethernet is a commonplace occurrence in our daily life. To be most effective, Gigabit Ethernet must be capable of operating over widely-installed cable plants. Nowadays, copper UTP wiring is among the widely deployed cable plants in the world. Thus 1000BASE-T is an attractive option for network mangers. In addition, 1000BASE-T is an important technology in Gigabit Ethernet mainly for the following reasons:
Firstly, since Category 5 is the dominant horizontal/floor cabling installed inside buildings, the 1000BASE-T technology enables network planners to deploy Gigabit Ethernet technology over their installed Category 5 cabling plants. This is important because the horizontal cabling is very difficult to be replaced as it is located inside a wall, ceiling, or raised floor and dispersed across many wiring closets. Secondly, as copper physical sublayers (PHYs) are expected to be less expensive than optical PHYs, 1000BASE-T ports will be cheaper than 1000BASE-X ports. Finally, just as explained above, 1000BASE-T enables network managers to preserve their investment in existing Ethernet equipment. In a word, 1000BASE-T is a cost-effective solution for Gigabit Ethernet.
How 1000BASE-T Works in Gigabit Ethernet Applications
As an extension of standard Ethernet technologies to gigabit-level network speeds, 1000BASE-T is normally implemented using the commonly installed category 5 cabling or enhanced category 5 cabling version of UTP cabling (for example, category 5e). Unlike using only two pairs of wires in 10BASE-T and 100BASE-T networks, 1000BASE-T uses all four cable pairs for simultaneous transmission in both directions through the use of adaptive equalization and a five-level pulse amplitude modulation (PAM-5) technique.
In the process of transmitting a 1000 Mb/s data stream over four pairs of Category 5 twisted pair cables, there are certain associated problems caused by factors as attenuation, crosstalk, and echoes arising from full-duplex transmission over single wires. To solve these problems, special filters, the PAM-5, forward error correction techniques and pulse shaping technologies are specified to make 1000BASE-T a functional and reliable networking technology. The special filters are for hybrid circuits used in full-duplex transmission over single wires. The PAM-5 provides better bandwidth utilization than binary signaling. Forward error correction techniques provide a second level of coding that helps to recover the transmitted symbols in the presence of high noise and crosstalk. Pulse shaping technologies match the spectral characteristics of the transmitted signals to those of the channel in order to maximize the signal-tonoise ratio.
Providing highly cost-effective shared gigabit service, 1000BASE-T is welcomed by many Gigabit Ethernet technology adopters. Therefore, there are many 1000BASE-T products available in the market. For instance, 1000BASE-T SFP transceivers are modules used for Category 5 copper wire. As a leading manufacturer and supplier of fiber optical products, Fiberstore provides various 1000BASE-T products, including the above mentioned .
Originally published at http://www.fiber-optical-networking.com/
