100BASE-T is a good way to improve network performance by allowing the customer to deploy Fast Ethernet over the existing network infrastructure. By providing speed of 100 Mb/s—10 times the speed of Ethernet transmission over CAT5 unshielded twisted pair (UTP) copper cabling, it’s one of the most affordable and widely installed cabling infrastructures in networking systems. This article places focus on introducing Fast Ethernet (100BASE-T) basic information.

Fast Ethernet is an extension to the IEEE802.3 Ethernet standard to support service at 100 Mbps. It is virtually identical to 10BASE-T, in that it uses the same media access control (MAC) layer, frame format, and carrier sense multiple access with collision detection (CSMA/CD) protocol. This means that network managers can use 100BASE-T to improve bandwidth and still make maximum use of investments in equipment, management tools, applications, and network support personnel. The 100BASE-T standard (IEEE802.3u, 1995) currently defines several physical layer signaling systems: 100BASE-TX, ,100BASE-T4 and 100Base-FX, among which 1000BASE-TX standard has risen far above the other two standards as the most popular Fast Ethernet implementation.

100BASE-TX operates over two pairs of Category 5 UTP, and uses Category 5 certified RJ-45 connectors. One pair is used for transmit and the other for receive. 100BASE-TX utilizes 3-level MLT (Multi-Level Transmit) signaling. With this coding system, each transmitted symbol represents one of three different levels (-1, 0, +1).

In its typical configuration, 100BASE-TX uses one pair of twisted wires in each direction, providing 100 Mbit/s of throughput in each direction (full-duplex). The configuration of 100BASE-TX networks is very similar to 10BASE-T. When used to build a local area network, the devices on the network (computers, printers etc.) are typically connected to a hub or switch, creating a star network. Alternatively, it is possible to connect two devices directly using a crossover cable.

100BASE-T4 requires four twisted copper pairs, but those pairs were only required to be category 3 rather than the category 5 required by TX. One pair is reserved for transmit (TX), one for receive (RX), and the remaining two will switch direction as negotiated. This means 3 pairs are used to transmit in each direction, which makes 100BASE-T4 inherently half-duplex. Unlike 100BASE-TX, 100BASE-T4 does not support full-duplex operation.

100BASE-FX is a version of Fast Ethernet over optical fiber. It uses a 1300nm near-infrared (NIR) light wavelength to transmit signal via two strands of optical fiber, one for receive and the other for transmit. It supports both half-duplex and full-duplex operation, 412 metres (1,350 ft) for half-duplex connections, and 2 kilometres (6,600 ft) for full-duplex connections over multi-mode fibers (MMF). Products for 100BASE-FX are available from a wide range of manufactures. For example, Fiberstore compatible Cisco GLC-GE-100FX and GLC-FE-100FX transceivers are fully compatible with Cisco devices. Besides, both the Cisco GLC-GE-100FX and GLC-FE-100FX support dual data-rate of 155Mbps and 2km transmission distance with MMF.

Auto-Negotiation provides automatic link testing and configuration for UTP signaling systems. All 100BASE-T systems using UTP go through Auto-Negotiation before establishing a link. During this link, here goes the processes:

• Check the link
• Exchange coded information defining the abilities of each link partner
• Go to an internal lookup table to determine the most common operation mode.
• Configure themselves as per the table.
• Turn off Auto-Negotiation.
• Open the link

By building networks with 100BASE-T for Fast Ethernet, the dedicated 100M-bps service can be shared by users. Fiberstore supplies 100BASE-T Fast Ethernet solutions, like the Cisco GLC-GE-100FX and GLC-FE-100FX transceivers mentioned above. Besides, Fiberstore also offers 10BASE Gigabit transmission products which are completely compatible with major brands, such as compatible HP J9150A. This compatible HP J9150A module provides the same functions as HP module. For more information about 100BASE-T and 10BASE-X solutions, you can visit Fiberstore.

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