Standard knowledge of Ethernet standard and network cable (copy)

Source: Internet
Author: User

Ethernet (EtherNet)

Originally created by Xerox, the Ethernet was developed jointly by DEC, Intel and Xerox three companies in 1980 as a standard. Ethernet is the most widely used local area network, including standard Ethernet (10Mbps), Fast Ethernet (100Mbps), Gigabit Ethernet (Mbps), and 10G Ethernet, all conforming to the IEEE802.3 Series standard specification.

(1) Standard Ethernet
The first Ethernet only has a 10Mbps throughput, and it uses the access control method of the CSMA/CD (carrier-listening multiplexing with collision detection), which is often referred to as the standard Ethernet for this earliest 10Mbps ethernet. There are two main types of Ethernet transmission media, that is twisted and coaxial cable. All Ethernet complies with the IEEE 802.3 standard, listed below are some of the Ethernet standards for IEEE 802.3, in which the preceding numbers represent the transfer speed in "Mbps", and the last number represents the single-segment cable length (base unit is 100m), and base represents "baseband" Broad means "bandwidth".
10base-5 Use coarse coaxial cable, the maximum segment length is 500m, baseband transmission method;
10base-2 using fine coaxial cable, the maximum segment length is 185m, baseband transmission method;
10base-t using twisted-pair cable, the maximum segment length is 100m;
1base-5 uses twisted-pair cable, the maximum segment length is 500m, the transmission speed is 1Mbps;
10BROAD-36 uses coaxial cable (rg-59/u CATV), the maximum network segment length is 3600m, is a kind of broadband transmission mode;
10BASE-F uses optical fiber transmission medium, the transmission rate is 10Mbps;

(2) Rapid Ethernet (Fast Ethernet)
With the development of network, the traditional standard Ethernet technology is difficult to meet the increasing demand of network data traffic speed. Before October 1993, for LAN applications that required more than 10Mbps of data traffic, only fiber-distributed Data Interface (FDDI) was available, but it was a very expensive, 100MPBS-based, fiber-optic LAN. In October 1993, Grand Junction introduced the world's first Fast Ethernet hub fastswitch10/100 and network interface card FastNIC100, and the Fast Ethernet technology was formally applied. Subsequently, Intel, Synoptics, 3COM, Baynetworks and other companies have also launched their own Fast Ethernet devices. At the same time, the IEEE802 engineering group also studied the standards of 100Mbps Ethernet, such as 100BASE-TX, 100BASE-T4, MII, Repeater, and full duplex. March 1995 IEEE announces the IEEE802.3U 100BASE-T Fast Ethernet standard (Fast Ethernet), which starts the era of Fast Ethernet.
Fast Ethernet has many advantages compared with the original 100Mbps bandwidth, which is mainly embodied in the Fast Ethernet technology can effectively protect the user's investment in cabling infrastructure implementation, it supports 3, 4, 5 twisted pair and fiber connection, can effectively use the existing facilities.
The lack of Fast Ethernet is also the lack of Ethernet technology, that is, Fast Ethernet is still based on carrier-listening multiplexing and Collision detection (CSMA/CD) technology, when the network load is heavy, it will reduce the efficiency, of course, this can be used in exchange technology to compensate.
100MBPS Fast Ethernet standard is also divided into: 100base-tx, 100BASE-FX, 100base-t4 three sub-categories.
100BASE-TX: is a Fast Ethernet technology that uses Class 5 data-level unshielded twisted pair or shielded twisted-pair wires. It uses two pairs of twisted pair, one pair for sending, and one pair for receiving data. The 4b/5b encoding method is used in the transmission, and the signal frequency is 125MHz. Complies with the EIA586 Class 5 cabling Standard and IBM's SPT 1 class cabling standard. Use the same RJ-45 connector as the 10base-t. Its maximum network segment length is 100 meters. It supports full-duplex data transfer.
100BASE-FX: is a fast Ethernet technology using fiber optic cables with a maximum distance of 550 meters using Singlemode and multimode fiber (62.5 and 125um) multimode fiber connections. The maximum distance between single-mode fiber connections is 3000 meters. The 4b/5b encoding method is used in the transmission, and the signal frequency is 125MHz. It uses a MIC/FDDI connector, ST Connector or SC Connector. Its maximum segment length is 150m, 412m, 2000m, or up to 10 km, which is related to the type of fiber and mode of operation used, and it supports full-duplex data transfer. The 100BASE-FX is particularly suitable for environments with electrical disturbances, large distances, or high-security environments.
100BASE-T4: It is a fast Ethernet technology that can use 3, 4, Class 5 unshielded twisted pair or shielded twisted pair wire. It uses 4 pairs of twisted pair, 3 pairs for transmitting data, and 1 pairs for detecting conflicting signals. The 8B/6T encoding method is used in the transmission, the signal frequency is 25MHz and conforms to the EIA586 structured cabling standard. It uses the same RJ-45 connector as the 10base-t, with a maximum network segment length of 100 meters.

(3) Gigabit Ethernet (GB Ethernet)
With the deep application and development of Ethernet technology, the demand of enterprise users for network connection speed is more and more high, in November 1995, IEEE802.3 Working Group appointed a high-speed research group (Higherspeedstudy Group) to study the speed of fast Ethernet to higher. The study group studied the feasibility and method of increasing the speed of Fast Ethernet to 1000Mbps. In June 1996, the IEEE Standards Board approved a Gigabit Ethernet Solution authorization Request (Gigabit Ethernet Project Authorization request). The 802.3Z Working Committee was subsequently established by the IEEE802.3 Working Group. The purpose of the IEEE802.3Z Committee is to establish a Gigabit Ethernet standard that includes full-and half-duplex operations at 1000Mbps communication rates, 802.3 Ethernet frame formats, carrier-based multi-channel access and Collision Detection (CSMA/CD) technology, Support for a repeater (Repeater), 10base-t, and 100base-t backwards-compatible technology in a conflict domain Gigabit Ethernet has easy-to-migrate, easy-to-manage features for Ethernet. With the flexibility to handle new applications and new data types, Gigabit Ethernet is an extension of the great success of the 10Mbps and 100Mbps IEEE802.3 Ethernet standards, providing 1000Mbps of data bandwidth. This makes Gigabit Ethernet a strategic choice for high-speed, broadband network applications.
1000MBPS Gigabit Ethernet is currently available in the following three technical versions: 1000BASE-SX,-LX and-CX. The 1000BASE-SX series uses low-cost short-wave CDs (compact disc, disc lasers) or vcsel (Vertical cavity surface emitting laser, vertical cavity surface light emitting lasers) transmitters While the 1000BASE-LX series uses relatively expensive long-wavelength lasers; The 1000BASE-CX series is intended to connect high-performance servers and high-speed peripherals using short jumper cables between wiring.

(4) 10G Ethernet
Now that the 10Gbps Ethernet standard has been formally developed by the IEEE 802.3 Working Group in 2000, 10G Ethernet is still used in the same form as in previous 10Mbps and 100Mbps Ethernet, allowing direct upgrades to high-speed networks. Also use the IEEE 802.3 standard frame format, full duplex service, and traffic control mode. In half-duplex mode, 10G Ethernet uses the basic CSMA/CD access method to resolve the conflict of shared media. In addition, 10G Ethernet is used by the IEEE 802.3 group to define the same management objects as the Ethernet. In short, 10G Ethernet is still Ethernet, but faster. However, due to the complexity of the 10G Ethernet technology and the original transmission media compatibility issues (at present only in the optical fiber transmission, and the original enterprise commonly used twisted pair is not compatible), and the cost of such equipment is too high (generally 2 ̄9 million), so this kind of Ethernet technology is still in the initial stage of research and development, has not been applied in real

                              Cable Standard

Five types of line identification is "CAT5", the bandwidth of 100M, applicable to the network of less than hundred trillion, the logo of the Super Five line is "CAT5e", the bandwidth 155M, is the current mainstream products, six lines of identification is "CAT6", bandwidth 250M, for the erection of gigabit Network, is the trend of future development.
"Super Five Class" refers to the Super Five class unshielded twisted pair (utp-unshielded Twisted pair)
unshielded twisted pair cables consist of a multi-pair twisted pair and a plastic sheath. The five categories refer to the five different quality levels defined by the International Electrical Industry Association for twisted pair cables.
Super Five unshielded twisted pair is a cable that appears after improving some performance of the existing five types of shielded twisted pair, many performance parameters, such as near-end crosstalk, attenuation crosstalk ratio, return loss and so on have been improved, but its transmission bandwidth is still 100MHz.
The super five twisted pair is also made of 4 pairs and 1 anti-pull lines, the color of the line pair is identical to the five twisted pairs, namely white orange, orange, white green, green, white blue, blue, white brown and brown. The bare copper wire diameter is 0.51mm (Wire gage 24AWG), and the diameter of 0.92MM,UTP cable is 5mm.

Although the ultra five unshielded twisted pair can also provide up to 1000mb/s of transmission bandwidth, it often requires the support of expensive special equipment. Therefore, it is usually only applied to 100MB/S Fast Ethernet, which realizes the desktop switch-to-computer connection. If you are not ready to upgrade your network to Gigabit Ethernet later, you may want to use the Super five unshielded twisted pair in horizontal cabling.

Category "Six" means six unshielded twisted pair
The parameters of the class six unshielded twisted pair are greatly improved, and the bandwidth is extended to 250MHz or higher. Type six twisted pair in the form and structure with five or super five twisted pair have a certain difference, not only increased the insulation of the cross skeleton, the twisted pair of four pairs of lines placed in the cross skeleton four groove, and the cable diameter is also thicker.
The cross skeleton of the cable center rotates with the change of length, the four pairs of twisted pair are stuck in the groove of the skeleton, and the relative position of four pairs of twisted pair is maintained, and the balance characteristic and crosstalk attenuation of the cable are improved. In addition, the balance structure of the cable is guaranteed to be not damaged during installation. The six unshielded twisted pair has a bare copper wire diameter of 0.57mm (Gage 23AWG) and an insulated wire diameter of 1.02MM,UTP cable with 6.53mm.

Super Five class or six class
According to the different electrical performance, twisted pair can be divided into three categories, five categories, Super Five class, six class and seven twisted pair. The different categories of twisted pair price difference is large or even large, the scope of application is very different.

In addition to the traditional voice system still uses three types of twisted-pair, network cabling is currently in the use of Super Five class or six unshielded twisted pair. The five types of unshielded twisted pair can still support 1000base-t, but because the price is similar to the Ultra five unshielded twisted pair, it has gradually faded out of the wiring market.

Class six unshielded twisted pair although the price is high, but because with super five class cabling system has very good compatibility, and can very well support 1000base-t, so is slowly become the favorite of integrated wiring. The class seven shielded twisted pair is a new cabling system that, despite its excellent performance, is expensive. The construction of complex and selectable products is less, so it is seldom used in wiring engineering.

The class six unshielded twisted pair provides excellent support for Gigabit Ethernet and achieves 100m transmission distances. As a result, class six cabling systems are widely used in the routing of sub-server rooms, as well as horizontal cabling that retains the ability to upgrade to Gigabit Ethernet. The expected life expectancy of the cabling system is at least 10 years, according to the International cabling standard ISO 11801. As a long-term basic investment, the integrated cabling should fully consider the potential needs of the network and the development of cabling system, therefore, under the conditions of capital permitting, it is recommended to choose six types of products to build cabling system.

Considering the future application needs of the network, it is theoretically necessary to install the most advanced cabling products, since the installation of cables is often difficult to re-update the replacement, basically, a cabling system to apply at least 10 as a standard, capable of supporting 4 to 5 generations of network equipment performance updates, If future network devices need a better cable to improve data speed.

Then, the use of class six cable instead of the Super five cable is unavoidable, but these cable re-construction is very expensive, so even though the price of six products is slightly more expensive than the ultra-five products, but in order to reduce future network upgrade problems, six products are still worth considering.

"Super Six Class"
Belden IBDN developed a high-performance cabling system with a target of 40 ℃ or more, and formally launched the IBDN 4800LX system at the end of 1999, with the final indicator reaching 300MHz bandwidth, which can still reach the 20 ℃ performance of the 6-class standard at 50 ℃. In order to differentiate from the general 6 class cabling system, this bandwidth performance is much more than the 6 class of cabling called Super 6 class.
Most of the Super 6-class cabling uses the same modules and jumpers as the brand's 6-class cabling, so they are primarily differentiated on the online cable. IBDN's Ultra 6 class cable 4800LX from the beginning of the target is fixed at a higher temperature normal operation, so one of its cable construction features is a large wire diameter, the diameter of the transmission conductor from the General 6 class 0.5mm (24AWG) increased to 0.6mm (23AWG) There are also some manufacturers in the beginning of the Super 6 type of cable using 24AWG and try to improve the next method, but the improvement of the cable in 2002 to add its wire diameter to 23AWG. Another feature is the addition of a 10-zigzag line pair divider between 4 twisted pair pairs. Without a cross-section, a pair of lines in the cable may be trapped in a gap between the two conductors of another pair of wires, the spacing between the lines decreases and the crosstalk problem is aggravated. Together with the outer sheath of the cable, the divider strips 4 pairs of conductors tightly in their design position and slows down the wire-to-crease of the cable bends, reducing the performance during installation. The 4800LX is the first ultra 6-class cable with a cross-divider, followed by a similar technique to emulate the cable.

Ethernet standard and network cable standard common sense (copy)

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