Category Archives: 1000BASE-T

1000BASE-T Gigabit Ethernet over Category 5 Cable

Various copper and fiber choices are available on the market today. When deciding a cabling system, network managers should know how to choose the most appropriate cabling system for their network infrastructure in the long run. Many of the cabling installed today inside buildings is Category 5. Many factors, like punch down blocks, and patch panel connections, affect the performance of 1000BASE-T technology if not correctly implemented. This article gives an introduction to 1000BASE-T Gigabit Ethernet operation over the installed base of Category 5 cabling.

1000BASE-T and Category 5 Cabling

1000BASE-T is a type of gigabit Ethernet networking technology that uses copper cables as a medium. 1000BASE-T uses four pairs of Category 5 unshielded twisted pair cables to achieve gigabit data rates. There should be no need to replace existing Category 5 cabling to use 1000BASE-T. The standard is designated as IEEE 802.3ab and allows 1Gbps data transfers for distances of up to 330 feet. 1000Base-T came into wide use in 1999, gradually replacing fast Ethernet for wired local networks simply because it was 10 times as fast. Equipment and cables are very similar to previous Ethernet standards and by 2011 were very common and economical. These were the biggest factors that ensured this standard’s wide acceptance. The 1000BASE-T product is designed to operate over Category 5 cabling. The image below shows how 1000BASE-T works.

1000BASE-T

Gigabit Bandwidth over Category 5 Cabling

1000BASE-T uses a symbol rate of 125 Mbaud (A 125 Mbaud symbol rate is required because 100BASE-TX uses 4B/5B coding), but it uses all four pairs for the link and a more sophisticated five-level coding scheme. In addition, 1000BASE-T sends and receives simultaneously on each pair. Combining 5-level coding and 4 pairs allows 1000BASE-T to send one byte in parallel at each signal pulse. 4 pairs 125 Msymbols/second X 2 bits/symbol = 1Gbps.

Problems During Cable Installation

Of course, it isn’t quite this simple. In addition to moving the symbols across the link, 1000BASE-T must also deal with the effects of return loss and crosstalk, and other factors.

Return loss measures the amount of reflected signal energy resulting from impedance changes in the cabling link. If too much energy is reflected back onto the receiver, the device does not perform optimally. Factors that affect the return loss are:

  • The number of transition points, as there is a connection through an RJ-45 to another connector, a patch panel, or device at each transition point.
  • Removing the jacket that surrounds the four pairs of twisted cable. When RJ-45 connections are made, this is minimized to 1 1/4 inch (32 mm).
  • Untwisting any pair of the twisted-pair cabling. It is important that any untwisting be minimized to 3/8 inch (10 mm) for RJ-45 connections.
  • Cabling or bundling of multiple Category 5 cables. If not correctly implemented, this can adversely affect all cabling settings.

Crosstalk is unwanted signals coupled between adjacent wire pairs. Since 1000BASE-T uses all four wire pairs, each pair is affected by crosstalk from the adjacent three pairs. Near-end crosstalk (NEXT) is crosstalk that appears at the output of a wire pair at the transmitter (near) end of the cable. Far-end crosstalk (FEXT) is a measure of the unwanted signal coupling from a transmitter at the near-end into a neighboring pair measured at the far-end. Crosstalk is characterized in reference to the transmitter.

Conclusion

For optimum performance of your 1000BASE-T product, it is important to fully qualify your cable installation and ensure that it meets or exceeds Category 5 specifications. Fiberstore provides various Category 5 cables and 1000BASE-T optical transceivers for your applications. For example, Finisar FCLF-8520-3 1000BASE-T copper SFP RJ-45 transceiver, and Cisco GLC-T 1000BASE-T SFP copper RJ-45 transceiver, are compliant with the Gigabit Ethernet and 1000BASE-T standards as specified in IEEE 802.3 and 802.3ab. These SFP transceivers link your switches and routers to the network. They are 100% functionally tested, and compatibility is guaranteed.

1000BASE-T vs 1000BASE-TX

Networking may be straightforward, but the world of networking terminology is not. Even when you’ve been steeped in business of Ethernet for many years, you may still get confused by some of the terms. What are 1000BASE-T and 1000BASE-TX and the difference between them? In this post, this Ethernet network naming convention will be tackled.

What Are 1000BASE-T and 1000BASE-TX?

1000BASE-T and 1000BASE-TX, their names share a lot in common, except that the latter has one more letter “X”. What do they mean? The “1000” refers to the transmission speed of 1000 Mbps. The “BASE” refers to BASEband signaling, which means that only Ethernet signals are being carried on the medium. The “T” refers to the twisted pair cables that the technology uses. 1000BASE-T is a shorthand designation by the Institute of Electrical and Electronics Engineers (IEEE). The standard is designated as IEEE 802.3ab and allows 1 Gbps data to transfer for distances of up to 100 meters.

1000BASE-TX is a physical layer standard similar to 1000BASE-T created and managed by Telecommunications Industry Association (TIA). It also referred to as TIA/EIA 854. 1000BASE-TX enables transmitting data at speeds of gigabits per second for up to 100 meters in length and is also maintained under the IEEE 802.3ab standard. 1000BASE-T and 1000BASE-TX are both types of gigabit Ethernet networking technology that uses copper cables as a medium.

How 1000BASE-T and 1000BASE-TX Work?

1000BASE-T is normally implemented using four pairs of the commonly installed Category 5 (Cat 5) unshielded twisted pair (UTP) cable or enhanced Cat 5 cabling version of UTP cable to achieve gigabit data rates. Transmitting a 1000 Mb/s data stream over four pairs of Cat 5 twisted pair cables presents several design challenges to both the transmission system designer and standards developer. The challenges are due to signal attenuation, echo, return loss, and crosstalk characteristics of cables, as well as electromagnetic emissions and susceptibility. The 802.3ab standards specify special filters for hybrid circuits used in full-duplex transmission over single wires, a special five-level pulse amplitude modulation (PAM) encoding mechanism instead of binary signals, forward error correction techniques, and pulse shaping technologies to make 1000BASE-T a functional and reliable networking technology. The following picture shows 1000BASE-T.

1000base-t

As opposed to the four pairs of wires used in 1000BASE-T networks, 1000BASE-TX uses two pairs of wires for data transmission which enables transmitting data at speeds of 500 Mbps on Category 6 or 7 UTP cables. The following picture shows 1000BASE-TX.

1000base-tx

What Are the Differences Between Them?

1000BASE-T can be used in data centers for fast server switching or in desktop PCs for broadband applications. The biggest advantage of 1000BASE-T is that it can use existing copper cabling, negating the need to rewire the system with newer optical fiber cables. However, 1000BASE-TX requires Cat 6 or 7 cabling. The design of 1000BASE-TX does not require hybrids, nor does it necessitate echo cancellation, so its electronics can be much less expensive than comparable 1000BASE-T electronics. Though 1000BASE-TX enables the building of devices with less circuitry to support, it has not been as commonly used as 1000BASE-T, due to the high cost of Cat 6 and 7 cable requirements and the falling cost of 1000BASE-T products.

1000BASE-T and 1000BASE-TX are different standards. As a result, they have different connection requirements. For each of them, there are various kinds of compatible SFP copper transceiver modules For example, compatible SFP copper transceiver modules like QFX-SFP-1GE-T, FCLF-8520-3, and HP JD089B are for 1000BASE-T network connection; and compatible SFP copper transceiver module like Cisco GLC-T is for 1000BASE-TX network connection.

1000BASE-T Technology—Gigabit Ethernet over Copper

The following picture shows a GLC-T compatible 1000BASE-T copper SFP transceiver module. Looking at it, you may ask: what is 1000BASE-T? As a member of the Gigabit Ethernet family of standards, 1000BASE-T came into wide use in 1999, gradually replacing fast Ethernet. Equipment and cables are very similar to previous Ethernet standards. By 2011, it has been very common and economical. In this post, some detailed information about 1000BASE-T will be shown.

GLC-T transceiver module

1000BASE-T Definition

1000Base-T is a shorthand designation by the Institute of Electrical and Electronics Engineers (IEEE). The “1000” refers to the transmission speed of 1000 Mbps. The “BASE” refers to baseband signalling, which means that only Ethernet signals are being carried on the medium. The “T” refers to the twisted pair cables that the technology uses (e.g. the common category 5 in use today). 1000Base-T is a type of gigabit Ethernet networking technology that uses copper cables as a medium. The standard is designated as IEEE 802.3ab and allows 1 Gbps data to transfer for distances of up to 100 meters.

How 1000BASE-T Works

1000BASE-T—How does it work? This section provides a brief overview of the technical foundations to 1000BASE-T.

1000Base-T is an extension of standard Ethernet technologies to gigabit-level network speeds. 1000Base-T is normally implemented using four pairs of the commonly installed category 5 unshielded twisted pair (UTP) cable or enhanced category 5 cabling version of UTP cabling to achieve gigabit data rates. 1000Base-T uses all four pairs of wires in standard UTP cabling, as opposed to the two pairs of wires used in 10BaseT and 100BaseT networks. Transmitting a 1000 Mb/s data stream over four pairs of category 5 twisted pair cables presents several design challenges to both the transmission system designer and standards developer. The challenges are due to signal attenuation, echo, return loss, and crosstalk characteristics of cables, as well as electromagnetic emissions and susceptibility. The 802.3ab standards specify special filters for hybrid circuits used in full-duplex transmission over single wires, a special five-level pulse amplitude modulation (PAM) encoding mechanism instead of binary signals, forward error correction techniques, and pulse shaping technologies to make 1000Base-T a functional and reliable networking technology. The picture below shows a UTP cable.

UTP cable

Applications and Advantages of 1000BASE-T

1000BASE-T can be used in data centers for server switching, for uplinks from desktop computer switches, or directly to the desktop for broadband applications. It is intended mainly for connecting high-speed hubs, Ethernet switches, and routers together in wiring closets; for switch-switch connections in backbones; for switch-server connections; and for horizontal cable runs to high-speed workstations. The biggest advantage of 1000Base-T is that the existing copper cabling can be used, negating the need to rewire the system with newer optical fiber cables. Other 1000Base-T benefits include compatibility with existing network protocols (such as IP, IPX, and AppleTalk), network management platforms and applications.

Fiberstore is a professional manufacturer and supplier for optical fiber products and provides various kinds of 1000Base-T SFP transceivers like HP JD089B compatible SFP copper transceiver module, FCLF-8520-3 compatible SFP copper transceiver module, and QFX-SFP-1GE-T compatible SFP copper transceiver module, branded by many famous companies, such as Cisco, Finisar, Juniper, and HP. Those 1000Base-T SFP transceivers are compatible with the Gigabit Ethernet and 1000BASE-T standards as specified in IEEE 802.3z and 802.3ab.