Considerations for applying the network cabling system on campus

This article mainly explains how to correctly select the network cabling system and precautions in the campus network system. When using the campus network system, many people may understand the network cabling system, it doesn't matter. After reading this article, you will certainly have a lot of GAINS and hope to help you solve the problem.

1. FF Optical Fiber Connector product materials (indoor twisted pair wires)

According to authoritative statistics, more than 70% of network faults are caused by twisted pair wires. I believe in this sentence. We believe that our colleagues engaged in system integration often encounter "inexplicable" problems. For example, when the network is disconnected; when the distance is near, the distance will be a little longer (not more than 100 M); when 10 Mbps is normal, Mbps is not normal; the number of workstation is small, the task is not very busy, and it still uses cat5e lines, and the network speed is surprisingly slow.

The twisted pair wire technology was born at AT&T In The Middle Of 1980s. It was introduced to China in the middle of 1990s. During this period, it went through four major application stages. First, from the middle of 1980s to the early 90 s, with the popularity of 10 Mbps Ethernet, three types of unshielded twisted pair wires have replaced various non-balanced cables (such as coarse and fine coaxial cables ). Then, from the early s to the mid s, with the vigorous promotion of Mbps Fast Ethernet, Category 5 unshielded twisted pair wires replaced Category 3 markets. Later, by the end of 1990s, with the full potential of the 1Gbase-T network, cat5e unshielded twisted pair wires became the mainstream of the network cabling system market. Now, with the official release of the standard for the TIA/EIA cat6 unshielded network cabling system, the official launch of 1Gbase-TX has gradually become the preferred product for key projects. Through this process, we can clearly see that the development speed of wiring is amazing. The so-called manufacturer's technical level of cabling for 15 or 20 years is completely impractical. The choice of twisted pair cable type must fully consider the development of network applications in a certain period of time in the future.

In the current situation, the campus network cabling system type should be selected, and areas with different network application levels should be treated with caution. For example, the student dormitory area, teaching area, teacher dormitory area, office area, logistics area and other networks use a gigabit trunk Based on cat5e twisted pair wires combined with a 10-Gigabit desktop, which is more than enough to deal with current applications, in the future, we can smoothly transition to a gigabit network to a desktop, which can truly meet the network application requirements for the next 10 to 20 years. However, in areas with high requirements on data transmission margin, such as the Library area, network center, scientific research center, and multimedia classroom, whether or not to uniformly adopt the cat5e system is worth seriously discussing. From the perspective of the whole process of several large-scale campus network construction projects that I have participated in, I believe that, when the financial conditions permit, it is necessary to consider using six types of cabling systems in these areas during initial design, to meet the demand for bandwidth in the future.

On the whole, cat5e cable is a very mature industrial product. At present, the overall cost effectiveness of network applications is very high, and it is suitable for large-scale procurement of campus networks. However, it is worth noting that we must pay attention to preventing the abuse of fake and shoddy products. In the computer city where fake goods are flooded, various types of twisted pair wires from Yuan to several hundred yuan are dazzling. As a user, how can we identify genuine and false lines?

First, identify whether a cat5e twisted pair is a counterfeit manufacturer. Domestic users usually use cat5e cables of imported brands, because the quality of cat5e cables is indeed much better than that of domestic ones, and the product construction is rich and the project is easy to pass the acceptance test. Therefore, some illegal manufacturers in China began to copy foreign twisted pair wires. How can I sign off if it is fake? A technician who is engaged in cargo inspection at the Customs gave a simple inspection method: the imported twisted pair outer leather PVC material is usually made of DuPont (Du Pont) chemical materials, plastic outer skin tensile elasticity, fold a piece of network cable, if you can immediately bounce back, basically can think of this network cable as genuine. Cable outer covers produced by many counterfeit manufacturers in China are generally made of low-cost inferior PVC material. The outer skin of the finished twisted pair wires is thin or thick, but the tensile strength is usually very low.

Second, we need to test its speed. The phenomenon of "Selling sheep and dogs" also exists in the twisted pair cable market. Currently, the network is generally composed of cat5e and cat5e twisted pair wires, which are already obsolete products. However, some irresponsible twisted pair cable manufacturers, after becoming the mainstream in the market, will unsalable cat5e encapsulation change labels and packaging, often sold in the name of cat5e China Telecom broadband line. This type of inferior cat5e linear cables can be significantly lower than the regular cables of the same type. The implementation of such cables leaves little richness for construction providers. After the implementation of the network, the actual speed can only reach the level of cat5e cabling. This fraud method is very concealed and hard to be discovered by users.

Finally, the really good quality twisted pair has a certain heat resistance, tensile, flame retardant, easy to bend characteristics. You can test the twisted pair wires in a high-temperature environment. When the surrounding temperature of the twisted pair wires reaches 35 ℃ to 40 ℃, the outer skin will not become soft, but false. At the same time, in order to ensure the safety of cabling and connection, the outer rubber of a good twisted pair cable has strong tensile strength, but not false. In addition, the twisted pair Cable uses copper, some domestic manufacturers add other Cheap metals to copper to reduce costs during production. The performance is that the wire cores of inferior twisted pair wires are obviously hard and hard to bend than normal ones, it is easy to break during construction. In addition, the high quality twisted pair outer skin also has a flame retardant function. ul cm twisted pair has the characteristics of transverse non-combustion, and ul cmr twisted pair has the characteristics of horizontal and vertical non-combustion, ul cmp-grade twisted pair wires are flame retardant at high-burning temperatures of PVC materials. Fake goods are made of inferior materials and can be tested with fire. North America, South America, Asia Pacific, and China all adopt the North America-based cable fire prevention standard UL and National Electronical Code ), in some parts of Europe, low halogen or low smoke halogen-free green cable standards are adopted, however, the cables of this type of outer skin have some disadvantages, such as low burning point, spontaneous combustion, fire prevention and soft outer skin, and the electrical characteristics of cables are easy to be damaged by construction.

It should be noted that, such as Jiangsu leting Cable Factory, Shanghai kanghua Cable Factory, Jiangsu Zhongtian Cable Factory, and other domestic cable factories, at present, multiple production lines have been introduced for domestic OEM production for multiple foreign brand products. This is called OEM in the IT industry. I was invited to visit some of these factories and found that many foreign brands of twisted pair wires (including cat5e, cat5e, and cat6) are produced here. The products produced in the same production line have different brands, the price difference is also very large, OEM products are usually two to three times the price of the original brand products. Therefore, when selecting a product, you must make a careful distinction. Instead of selecting a foreign brand for cabling, you can choose a high-quality product of the same type imported from abroad to avoid the failure of the network wiring system construction name. The construction of many campus network cabling systems cost RMB from original imports. In fact, they have bought domestic products labeled with foreign brands, wasting a lot of valuable money.

2. Work Area jumper

Manufacturers usually claim the importance of dedicated jumpers for the overall performance of the network cabling system. I believe that the advantages of dedicated jumpers mainly include the following advantages:

First, the electrical performance of the dedicated jumper is higher than that of the manual production product. Dedicated jumpers and self-made Jumpers are used to test the same cat5e cabling link. Generally, the channel performance difference is about 30%. Secondly, the dedicated jumper adopts the multi-core wire core (usually 8 cores) and dedicated Wire Core fixing technology, the physical characteristics, especially the flexibility of jumper and the reliability of RJ45 contact, are significantly higher than the manual jumper made by the horizontal single-core twisted pair. Therefore, dedicated jumper has a long service life and higher reliability. Finally, the impedance matching performance of dedicated jumpers from specialized cabling suppliers is better. The production standards of cabling manufacturers are usually far higher than industrial standards. I have visited the R & D laboratories of a well-known international brand, and the cabling channel impedance production standards are 100 Ω + 6 Ω, that is, the impedance error range of industrial finished products of this brand is controlled within 94 Ω to 106 Ω, which is far higher than the requirements of the international standard plus and minus 15 Ω. The full channel product applications of the same brand of products, the coupling performance between different components products can reflect the manufacturer's laboratory design standards, to minimize the signal reflection caused by impedance mismatch, when such signal reflection is severe, the packet loss rate of network data is astonishing, which greatly affects the actual running speed of the network.

However, in practical campus network engineering applications, we found that the disadvantages of large-scale application of dedicated jumper are also very obvious. First, the price of the original patch cord is too high compared with the cost of 10 yuan for manual patch cord production. Second, the specification of the original jumper is limited, usually only 3 feet, 5 feet, 7 feet, 10 feet and other specifications, lack of application targeted. For example, the jumper in the faculty and staff residential buildings on the campus network is a headache. In addition, the supply cycle of the dedicated jumper is also difficult. Because the application of dedicated jumper is not large, the retail circulation channels are very poor. It is hard to imagine that it takes 3 months for a user to order from abroad to buy an original jumper!

The author believes that, as an important part of the campus network cabling system, jumper issues need to be carefully analyzed. Generally, the jumper in the equipment room and management room may take into account a large number of plug-ins, which has high requirements on product reliability. We recommend that you select the original jumper at a time based on port usage and retain sufficient spare parts (generally 10% of the purchased quantity ). The jumper in the work area can be manually created and pressed by RJ45 clamp based on the specific application requirements. There are two main issues worth noting: first, RJ45 crystal head and cable must select products with good quality control to meet the requirements of system impedance matching to the maximum extent; secondly, manual Jumper should pay attention to the line order, in principle, the EIA/TIA 568B standard is recommended for better system compatibility.

The methods described above are limited to system applications of the cat5e category. When cat6 network cabling systems are used for campus networks and jumpers are selected, you can only select cat6 jumpers for the system to meet the design requirements. cat6 jumpers cannot be customized. However, we can also adopt a step-by-step approach to temporarily use manual jumpers to meet the cat5e application standards. In the next few years, when the network is transitioned to a gigabit desktop, we will then order dedicated cat6 jumpers for phased and rational application.

3. workspace panel

The choice of workspace panel is easily overlooked. The Panel provided by the system integrator is often unsatisfactory in terms of functionality and appearance, and it is difficult to satisfy. As a user, we have the right to choose products with fine workmanship and complete functions.

I once visited the campus network of a school. nearly 8 million of the campus networks are named "leading in China and internationally. During the visit, I fully experienced the luxurious and well-organized configuration of the school's network center data center and regional management center data center. In stark contrast, the work area of the network cabling system uses a simple and non-innovative domestic counterfeit panel, which forms a clear contrast with the school office decoration style, some teachers who do not know the truth even doubt whether such poor products in the office are really worth the money.

The panel of the work area must have the following features:

1) General: high degree of generalization, wide combination range, choose imported PC plastic as panel material, good strength, smooth appearance. The Panel frame has a right angle (type) arc angle (type) and a variety of styles to choose from;
2) Slim: The Panel Thickness generally does not exceed 6mm. The product is light and beautiful;
3) Easy: The snap-on connection is easy to install and the installation screws are shielded. The installation screws are more concise and bright in appearance, and can work closely with each other even after multiple disassembly and removal;
4) colorful: The Panel can be selected in multiple colors to meet the indoor decoration requirements for various occasions and environments.

Currently, the vast majority of well-known wiring product suppliers can provide imported or domestic National Standard Panels for users to choose from. There are two main types of panel for import: one is the North American style panel, which is represented by the United States. This type of panel usually does not include dust spring covers, but uses a plug-in type dust cover. The advantage is that the RJ45 module can be installed on the panel in any way of 90 ° or 45 °, and has good functions. Another European style is represented by French, German, and English products. These panels are usually equipped with dust-proof spring LVS and replaceable label blocks. Their products are quite elegant and elegant, fully embodies the personality style. Due to the global popularity of wiring products in the United States, electrical panel manufacturers in Europe have also customized European-style panels for wiring manufacturers in the United States for users with different preferences, A typical example of this is China's first building-Shanghai Jinmao Tower. It is said that Jinmao building has installed more than 20000 information points. The full set of network cabling systems adopts AVAYA cat5e products, and all its panels adopt European-style products originating in France.

At present, after years of technological innovation, domestic panel manufacturers headed by songben electric have also launched the corresponding network wiring system supporting panels for users to choose from. These products usually have a strong appearance aesthetic and a suitable price, but there is still a certain gap between the product manufacturing process and product service life and the imported products.

In addition, there are some Counterfeit imported panels produced by small-scale manufacturers in jiangyi and zheyi belts. These products are often rough and of poor quality, but they are cheap. In order to reduce costs, system integrators often like to recommend similar products. Many schools also neglect to guard against the impact on system performance. It seems that a small problem has damaged the external image of the entire network cabling system.

4. Lightning Protection

In addition to the outdoor cables, special outdoor lightning-proof and armored cables should be used as the standard for campus network cabling systems. The grounding of outdoor optical cables is also worth your attention. There are two types of lightning intrusion: direct lightning attacks and induction lightning. In general, it is very unlikely that the network equipment in the building is directly hit by lightning. Generally, it is not necessary to install the equipment that protects the direct hit by lightning. Inductive lightning is the powerful electromagnetic field changes produced by lightning and the overvoltage induced by the conductor, and lightning strikes are formed by overcurrent. There are three main ways for inductive lightning to intrude into electronic equipment and computer systems: first, the ground potential of lightning counterattacks the voltage through the grounding body intrusion; second, lightning is infiltrated by the AC power supply line; finally, lightning is infiltrated by communication signal lines. If you do not manage the form or method of intrusion, network devices and computer systems will be damaged to varying degrees.

The campus network cabling system lightning protection method recommended by experts is as follows: using optical fiber cables as the backbone network connection medium, lightning arresters do not need to be installed and can be directly laid over the air. If the twisted pair wires are used for outdoor connection, it is best to use a special metal armor Directly Buried Cable, otherwise the pipe must be buried. Indoor twisted pair wires, preferably laid in potential weak current metal trays or metal pipes, metal trays and metal pipes need to be well connected with the grounding system, grounding resistance shall not exceed 1 Ω. Network cabling systems cannot share metal trays or metal pipes with strong electrical wires. For an overhead cable, lightning protection measures must be taken at the network input end, such as the installation of lightning arresters, the addition of varistor, and a strong filter circuit, to suppress interference. Commonly used grounding resistance testing instruments include: Italy HT234E digital display precision grounding resistance tester, Austria GEOX double clamp multi-functional precision grounding resistance tester, French C.A6411-C.A6413 clamp grounding resistance tester, etc.

1. Comprehensive analysis of issues that should be paid attention to during the test of the Integrated Wiring System
2. Analysis of the future development direction of data center Cabling Technology
3. Analysis on how to improve the security of smart Wiring
4. Best Choice for low smoke, halogen-free, and flame-retardant cables and data center cabling
5. Measure the test taker's knowledge about the quality of network cabling products.