10 Gigabit copper cable: shielding and unblocking (1)

The UTP and unshielded FTP for category 5 and Category 6 copper cables have already reached a consensus in the industry. After the promulgation of the 10GBase-T standard, the battle for shielding and unblocking 10g copper cables is now in front of us. When more and more 10g copper cable products are available and more mature, are they shielded or unshielded?

Debate stems from out-of-Line crosstalk

Before the promulgation of the 10GBase-T standard, IEEE has confirmed that foreign crosstalk is the main electrical parameter that limits the performance of the structured cabling system when the 10g transmission line is applied; 10GBase-T team also showed that external crosstalk is the most important noise source, and said that, unlike other noise sources, external crosstalk is statistically random, so even if advanced digital signal processor DSP is used) it is also difficult to reduce the harm of algorithms.

10 Gigabit transmission over copper cables, which is a major technological improvement because the transmission frequency is very high and the standard requires 250 MHz for the 500MHz6 cabling system ), this has the problem that the crosstalk between different lines in the outer skin of a cable is very high, this problem will become more prominent as the transmission frequency, signal level, and parallel lines in the outer skin increase the length. The high frequency of MHz will cause the problem of near-end crosstalk (that is, out-of-Line crosstalk) of external cables, which is considered to be the biggest limiting factor for increasing channel capacity.

ANEXT is defined as the interference of one line in the cable to the other line. The ANEXT interference between two lines of the same color is the most obvious, because their newlinks are the same in this pair of lines. The deeper consideration must be based on the comprehensive out-of-Line crosstalk, that is, PSANEXT, because there is also noise interference between all adjacent line pairs, not just between those lines of the same color. In addition to cables, the two ports adjacent to the distribution frame also have strong ANEXT interference.

To solve this technical problem, many technical innovations have been adopted in the industry, making it a reality to transmit 10 Gigabit copper cables at a distance of 100 meters. Specifically, the industry has adopted a lot of new designs, including cables, module structures, and connections, including the use of new materials, new manufacturing technology, change the relative position of the four pairs of cables, change the module printing circuit design, etc. to improve ANEXT performance, to meet the requirements of 10g transmission. Of course, because different vendors use different technologies, they have different opinions on recommendation of 10 Gigabit shielding and 10 Gigabit unblocking.

Shield priority supporters

Whether to block 10 Gigabit network connections or not, the industry's voice is also different. Tyco Electronics AMP and Simon introduced the first 10g shielding system to users.

"After entering the 10g application field, the shielding system will gradually become the mainstream product of copper cable ." Said Chen Yutong, Technical Director of Simon Greater China. Chen Yutong explained this issue in detail: Most of the users who plan to use the 10-Gigabit network technology in the IDC room are users of the data center, they require high Data Transmission Accuracy, strong anti-interference ability, low bit error rate, and high security. In terms of the current industry technology level, the 10 Gigabit shielding system is an ideal choice. Its wire diameter is smaller than the current 10 Gigabit unshielded), the construction process, distance, bending radius and other requirements are more conducive to the structural characteristics of the data center. The inherent characteristics of the shielding layer solve the influence of external crosstalk between adjacent cables, which not only improves the density of lines and ports, but also ensures stable and efficient signal transmission.

According to Tyco Electronics, in order to ensure the consistency of the overall system performance, if unshielded cables are used, you need to ensure proper isolation between all communication cables in the installed system, in this way, the cable jacket is used to separate the cables. However, the unshielded system does not allow mixed use of different cable types, while the shielded cable can be used together with any communication cable. In addition, shielding has two positive and negative effects: it can protect the circuit, shield external noise or interference signals, and at the same time limit the internal signal to the outside world radiation, this prevents the external environment from the noise produced by the cable itself. Of course, Tyco electronic AMP reminds users of the following: an important prerequisite for the use of the screen layer is to ensure that no current flows through the screen layer. By grounding the installed cable screen layer, the current can be blocked.

The cost advantage has become another argument for "blocking top supporters. Compared with the 10g shielded xg stp cabling system, the price of the unshielded cabling system is 5% higher. Chen Yutong also expressed a similar view: according to the current price, 10 Gigabit shielding is more cost-effective than 10 Gigabit unshielded systems, excluding the related cost savings on bridges and space.

For issues that users should pay attention to when selecting a 10 Gigabit shielding system, Chen Yutong said, minimize external crosstalk, prevent cable skin deformation, optimize cable slot/pipe filling rate, support for high-density installation, and facilitate installation.

Table 2: Reasons for priority in 10 Gigabit shielding systems

◆ Reasonable price
◆ Shannon Capacity) larger than 6A UTP
◆ Use the shielding method to prevent out-of-Line crosstalk, instead of space distance, so as to better eliminate out-of-Line crosstalk
◆ More suitable for confidential applications
◆ Meet various application requirements in different environments
◆ Protection against EMI and RFI in a noise environment, less pseudo-peak pulses and system interruptions, reducing noise from non-cable sources
◆ Shielded devices have been on the market for many years
◆ Unblocking top supporter

Whether it is a blocking system or a non-blocking system is preferred. The view of comms1_imax Solutions is different from that of Tyco Electronics and Simon USA. Comms?systimax Solutions believes that the GigaSPEED X10D UTP unshielded) and FTP shielded) Solutions provide the same functional advantages, it also surpasses IEEE 802.3an 10GBase-T cabling channel specifications and TIA Category 6A and ISO/IEC Class EA specifications. Whether UTP or FTP is used as the wiring media depends on factors such as performance, reliability, cost, environment, space, convenience of installation and use, and whether a good grounding point exists, depends on the installation/environment. For most users, the GigaSPEED X10D UTP unblocking solution is recommended for comms1_effecimax Solutions. This is a truly globalized, portable solution that keeps installation and maintenance convenient and beyond the standard. GigaSPEED X10D FTP shielding) The solution is mainly used in customer environments that prefer to block cabling. It overcomes the internal performance bottleneck of traditional shielding solutions and fully meets the performance requirements of 6A Class/Class EA.

The company has such a description in related technical whitepaper, which directly shows the viewpoint of comms?#imax Solutions: in the information technology field, it is generally believed that the foil shielding in the cabling infrastructure can meet the needs of IEEE 802.3an 10GBase-T applications in the network, and is the only method to eliminate crosstalk interference. Although the shielding system does have its own advantages, 10GBase-T applications do not need to be foil shielded in the wiring system.

At CommScope, we design, produce and sell unshielded twisted pair UTP solutions and unshielded twisted pair FTP solutions. We believe that, in terms of eliminating adjacent channel crosstalk interference, ISO/IEC 11801 EA-level 6A) 4-the advantages of symmetric UTP cabling solutions far exceed the advantages of Class 6 E installation) FTP system. Although FTP has some advantages in security and industrial applications for most data centers and users in commercial environments, EA-level 6A) UTP is still the preferred choice for copper Media Running 10GBase-T applications. We respect that FTP is the best choice for customers and are very willing to provide them with the best FTP solution on the market.