Gigabit Ethernet transmission based on structured cabling of copper cables

1. Work Summary
Recently, the IEEE is working on a new project the project is to develop a standard for the operation of Gigabit Ethernet (10GbE) transmission based on the current copper structured cabling system, which is collaborating with leading experts from integrated wiring, electrical, test equipment and system design, Panduit belong to one of the leading ranks, we have foreseen that with the future increase in transmission rate, cable and connecting devices will be required to have higher performance. In addition, compared to today's gigabit Ethernet, signal electrical processing technology performance will also be improved. Because of the need for wider bandwidth, the signal level will become lower, in the original gigabit Ethernet, not a very serious problem of the noise source, in the million Gigabit Ethernet, will become an important issue.

One of the sources of noise comes from cable crosstalk (extraneous crosstalk), and the team has finally confirmed that this is a major electrical indicator that can be used to measure the performance of Gigabit Ethernet based on structured cabling systems. At present, the signal processing electronic technology in dealing with foreign crosstalk, compared to other sources of noise, there is no very effective way. The way to suppress this noise is to improve the performance of wiring system, so that the wiring system itself has the ability to restrain noise. The research team is exploring a range of technologies to suppress noise, or develop systems for the transmission of Gigabit Ethernet in the current noise environment. They are currently focusing on a method to ensure that the installed cabling system supports Gigabit Ethernet.

Today, however, there is no standard for running Gigabit Ethernet on a structured cabling system based on copper cables. Please be careful that vendors claim that their products have gigabit Ethernet performance. No one has yet been able to claim that their products meet the performance standards of Gigabit Ethernet, nor is there a wiring vendor that can declare and verify that their products meet the performance standards of the current Gigabit Ethernet on the six-class cabling system.

By the end of this year, the team is likely to be transformed into a formal task force, at which point the group's goals will be clearly defined and the criteria expected to be finalized by 2006. Because there are many factors in the industry to determine the copper cable will still be chosen to pass a medium. As standardization organizations continue to work to improve the performance of these systems, while some new technologies are entering the market, Panduit will continue to lead the industry. ---http://bianceng.cn (computer science)

2. Current Ethernet Overview
In the current structured wiring system based on copper cable, we find a lot of interesting phenomena when we investigate the feasibility of running Gigabit Ethernet on this. End users, installers, contractors, and system integrators have found that they can also host more information on existing systems. Standard organization is to continue to improve the function of Ethernet and data transfer rate. As shown in Figure A, by 2006, in the Enterprise LAN market, the number of access ports will reach 1 billion, while the Ethernet data transmission rate is increasing at 10 times times the rate (see Figure B). At the same time, Ethernet is starting to adopt new devices such as wireless and broadband modems.
　
Gigabit Ethernet can be run on the current super five and six types of systems, and prior to the release of six standards, some forward-looking and new technology users have purchased the latest six categories of products for their systems to validate their performance. With six categories of standards available in June 2002, people have a strong confidence in six products. Now those who emphasize the six-class feature are starting to focus on whether they can run Gigabit Ethernet on their existing systems.

Standard organizations continue to support demand information for Ethernet, both data rates and functionality. An example of the new feature is the recent IEEE standardized project, which is a standard for transmitting DC power in a structured cabling system. This standard (IEEE 802.3af.) 1 will support a reliable power supply for Internet applications such as VoIP telephony. At present, the centralized network of voice, data and video becomes very popular, and it supports the application of structured cabling system based on copper cable.

3, pay attention to the reason of the transmission of Gigabit Ethernet based on UTP copper cabling System
As a result of the rapid growth in the market, including video conferencing, streaming video, internet-based voice telephony (VoIP), CAD and storage networks, bandwidth demand has also increased rapidly relative to the past few decades. Industry demand has led to a continuous improvement in the performance requirements of structured cabling systems. In addition to bandwidth, at the same time require a high reliable power distribution, to ensure that similar to VoIP and other high reliability requirements of IP products can work reliably. These requirements for bandwidth, power, and low cost can be expressed on a structured cabling system based on copper cables. Today, in the data center of the internal connection, the implementation of the million-gigabit fiber connectivity. The industry is beginning to focus on the lower cost of the million-gigabit solution based on copper cables. Compared to the million-gigabit fiber products, the first user object of the gigabit system based on copper cabling will be the data center, the data center has high density, low cost and high reliability requirements, and the application to the desktop may eventually be locked in Gigabit Ethernet. Therefore, in the next few years, the million-gigabit products may not be in the desktop application of the market, cabling system support is based on the value of technology.

4, IEEE million Gigabit Ethernet research group's goal
In November 2002, IEEE Standard released a team of researchers to work on the economic and technical feasibility of a gigabit Ethernet based on copper cables. IEEE approved the project for two reasons, the first reason is that there is currently a April 2002 release of the million-gigabit fiber wiring standards, but there is no Gigabit copper cabling standards. In addition, there is a big difference in the price of copper and fiber solutions, and IEEE standards are very interested in low-cost solutions for broadband connections. For IEEE, the universal standard for Gigabit Ethernet is to be international, including its broad market potential, compatibility with other Ethernet standards, technical feasibility and economic viability. The goal of the research team is to translate these requirements into actual operational content, making it an official standard.

5, the technical challenges facing
The IEEE research group has recently identified external crosstalk as the main electrical parameter limiting the performance of structured cabling systems. Foreign crosstalk is a coupling signal on a disturbed cable that comes from adjacent different cables. A wiring system mainly consists of cables and connectors, both of which determine the performance of the wiring system. Figure II describes how foreign crosstalk is coupled in a multiple cable unshielded twisted pair (UTP) connection system. To support Gigabit Ethernet, this crosstalk must be suppressed. Connectors must also be improved to achieve performance enhancements for the entire system. The size of the coupling crosstalk depends on the following factors:

• Distance between cables

• Dielectric constants between line pairs and dielectric coefficients of materials

• Distance and coupling length of the coupling source

• AWG density of line pairs and use of cables

• Cable's stranded density

• Number of cables generating crosstalk

• Number and frequency of signal sources

• Spatial distance between longitudinal and linear pairs
　
In the wiring system, these large number of crosstalk signals, relative to other noise signals, account for a large proportion. Because today the electronic transmitter that drives the Ethernet cabling system has little effect on the signal between neighboring cables, it can only eliminate very few extraneous crosstalk. Signal processing circuit chip vendors predict the use of electronic circuits can eliminate 5 db crosstalk noise, so in order to truly improve bandwidth, eliminate foreign crosstalk must rely on the wiring system itself. Figure three A describes the situation where the external crosstalk signal must be lowered in order to achieve a gigabit data transmission rate under the assumption of different basic cabling structures and cable lengths, and figure three B describes the performance improvements obtained with the panduit buffer jumper. Please note that more external crosstalk suppression is required when using long wiring lengths. If the six-class cabling system (according to the level of the cable that is set by TIA) does not use suppression or mitigation measures, the maximum distance to support Gigabit Ethernet is no more than 44 meters. For Integrity (dt600e) type six wiring, the performance will be higher, the maximum length of nearly 68 meters. In general, enhanced cabling can reduce attenuation, which is the same effect as increasing external crosstalk suppression, which can increase the length of the cable. In order to support the six-type cable on the 100-meter distance, then approximately must suppress 20 db of external crosstalk. If the buffer jumper is used, the maximum length can also be increased. In Figure three, we can see that the higher the quality of the wiring system, the higher its performance. If the electronic circuit of signal processing can restrain the external crosstalk of 5 db, the distance of the wiring can be increased by 10 meters.

In the wiring system, there are many ways to reduce the external crosstalk. Describes two different scenarios for new and installed cabling systems. In the newly installed cabling system, the newly introduced cable to improve the immunity of crosstalk can support the transmission of Gigabit Ethernet. There are several options to consider for support for installed cabling systems, including:

• Separate the cables from physics, especially within 20 m from the source of the signal;

• To separate the cables containing the Wan Shaoxin number in space as far as possible;

• Buffer jumpers with low attenuation and crosstalk suppression.

The characteristics of connectors used in Gigabit Ethernet are also very important. As a starting point to understand the importance of some parameters, the six-class connector frequency range can be pushed up to 625MHZ. Please note that the limit of frequencies is still not specified here, depending on the transceiver to be determined. For PAM-10 (level 10 pulse amplitude modulation) line encoding, the frequency limit is at least 500MHZ. The parameters are shown in Figure four. Some vendors claim that their products are good, conform to or exceed the parameters of these illustrations, and even try to show that their products meet the requirements of Gigabit Ethernet connections. To date, the standard group has not discussed the specification of connectors and the performance intent of connectors in cabling systems. An early definition of connectivity will cause a lot of trouble, as the industry is inspecting other important parameters that do not exist in the main parameter specifications of the existing six connectors. The extension performance of Class six cabling system is very important, but it is not enough for the specification that can support the gigabit rate Ethernet.

6. Possible Solutions
For new installations, a new type of cable with enhanced external crosstalk suppression capability is recommended, and the cable that is most likely to be qualified for this requirement is an enhanced six type unshielded twisted pair cable. This cable must be backward compatible with the current class six cable. New connector hardware must also be developed to match this new type of cable. For existing installations, there will be two ways to resolve, one way is to adjust the data transmission rate to achieve the wiring base can support the highest transmission rate. Another approach is to use a buffer to improve the existing cabling base to support all gigabit Ethernet rates. Because the industry is developing a data transfer rate for all Gigabit Ethernet, the buffer plan is the most likely.

The buffer plan under scrutiny is the adoption of enhanced buffer jumpers and other connected products, a strategy that is very similar to the process from five to five, typically five systems tested and, if required, certified as Super Five systems. And today's installed wiring system, if through some new requirements, can be certified as an enhanced type six system. If he did not pass, but also more than some of the minimum requirements, then the user has a more choice, can be used for cabling system buffer plan. An example of a buffer plan is to install a new enhanced jumper and a wiring rack connection. Once installed, the cabling system can be tested again and certified as an enhanced six class system. With this strategy, most of the wiring system has been installed can be used.

7. Summary and conclusion
In the wiring industry has not broken the next technical barriers in the case, UTP Copper cable is still a way to choose the wiring system. People are concerned about the compatibility of cabling systems already installed and newly installed cabling systems. It is noteworthy that, so far, the Gigabit Ethernet based on copper cable has not been promulgated by standard.