Shulou(Shulou.com)06/01 Report--

Development trend of Integrated cabling testing Technology

-- 2010 China Integrated cabling Market Development Summit

Yin Gang: Yin Gang, Technical Manager of Fluke Co., Ltd. Over the years, he has focused on the quality inspection and diagnosis of computer network technology, participated in the acceptance of local standards of Shanghai wireless local area network, and also served as one of the editors of many technical white papers in the integrated cabling working group.

Time is tight, but it's finally my turn. My time is 15 minutes. I will try to finish my speech at 13 minutes. Basically, there is a problem with testing, which is MPO. Do you want to test MPO? Some friends told me that the preset optical fiber has not been tested, in fact, it is a formal test, but some of our friends have thought of some ways. I have seen several photos they have taken of me, but I have not actually tested what they have done. In the photo, they omitted an intermediate compensation connector, which can be increased by about 0.3 to 0.5 decibels at most. How much can such a little help? Let's not forget that there is only such a short distance, within 300 meters, and the overall 10-gigabyte requirement basically cannot exceed about 2.78 decibels, so there is a "pseudo lift" of 0.3 or 0.5 decibels, which is actually quite considerable for 2.78 decibels.

The quality of residential wiring has always been neglected, the original is five types of lines, but some high-end housing, we found that there are still a lot of problems. Last week I went to test two high-end houses, one cost more than 4 million, two floors with an underground floor totaling three floors, and the other cost 14 million, a square meter of 70, 000 square meters. However, the design of the information base is relatively crude, or the grade is a little too different from its price. For example, the kitchen, bathroom, balcony and other information sockets are not designed, it is difficult to cope with information appliances and information leisure information equipment into the family; there is only one socket in the living room, which is obviously not enough compared with such a large living room.

Let's first talk about the diversity of wiring structure. Intelligent centers, green buildings, energy-efficient buildings, Ethernet, including the current relatively hot Internet of things, these actually pose a challenge to the wiring mode. We were familiar with the wiring structure, you found that they are not arranged in this way. But they do use it this way, and in terms of performance testing, as long as it meets the requirements, we have failed to keep up with some of its current specifications. Of course, this is a feature. In addition, there are more and more things, including visible light, infrared, and wireless access. Some are a little less mentioned, but they will be used in the Internet of things in the future, even using ultrasonic waves to connect sensors. Cabling in the data center, the main increase in requirements is 10 gigabytes for cables. But what exactly does ten thousand trillion choose? Now we all agree, 6A. But some users also complained to me that you mentioned 6A now, but why did you ask us to put so many 6 categories in the first place? In that case, you might as well let me choose 6A, you push a lot of 6 categories, what do you want me to do in the future? The cost of 6A is much higher than category 6 now, and you can't grow from category 5 to 6A. But we basically agree on what to use in the data center, using 6A. I personally have the same attitude, because there are several costs to consider in the data center. Is it all-optical or cable? is the cable shielded or unshielded? Basically, these choices have a lot to do with cost. The money is very small, but what should I do if I have to spend 10 trillion yuan? It's the unshielded 6A. Some management methods, structures and other changes in the data center are more frequent, which means that the basic links should remain unchanged as far as possible.

With regard to the detection content of the data center, what is mainly introduced is the external interference test, which has some requirements. Due to the time constraint, I will not talk about it any more. how to select the tested object? If you test it all, it may be an astronomical figure, of course, you don't have to test it all, just pick a few, pick out the worst and test the worst, otherwise, the massive test cannot be completed. There is also some type selection in the design stage, and many manufacturers have already begun to make some substantial advances. The selection test can guarantee the quality of the final system. From the 6A network built now, there are few external interference tests, because the TIA942 is divided into several levels, our country is divided into ABC, it is divided into one, two, three, four, level four requirements are very high. In addition, it requires a 1:1 physical backup. So what do we do? You haven't done a quality assessment before, so there's bound to be something wrong with the test. Second, jumper. The line is good. It's been tested. During the operation, it is found that there is something wrong with the operation of the equipment, take a jumper and go up to a pair, it still won't work. This is also a common problem. In fact, jumpers of six types and above were not allowed to be done by hand a few years ago, and now some manufacturers have come up with some micro-modules that can be made by hand, so there will be some problems in quality assurance, but for 6A, basically, it is not recommended to do jumpers by hand. How do you know if the quality of the jumpers you bought is up to standard? In fact, it is also very simple, test it. This is called an in-store test, or an on-site test. Jumper adapters are used for testing before entering the library.

What about high-speed optical fiber? Now there are more and more problems. I basically have to answer at least two such consultation and distress calls every month. Users say that I am upgrading from gigabit to 10 gigabit. I use OM3 optical fiber. I used to work in gigabit. Now I can't even connect with a 10 gigabit machine. The original detection of 10-gigabit optical fiber is basically in accordance with the first-level test, and the test is to measure attenuation and loss. For example, when there is an axis alignment error at the connection point of OM3 fiber, the refraction of light in it will be different, and the dispersion will increase. The common question is "there was no error code in the past, but why is it so high now that it is 10 trillion?" So, you can't just use the first-level test to measure 10 gigabit fiber. Dispersion has a great influence on 10-gigabit links, the earliest definition is to measure dispersion directly, but on-site dispersion is basically laboratory equipment, which is more expensive, bulky, inconvenient to operate, and too demanding for personnel. this scheme was rejected six years ago. The premise of six years is to use OTDR to measure, which can indirectly show the connection quality of the connector.

After measuring with high-precision OTDR, see if those connection points and fusion points can meet the requirements. There are also joints that are dirty, such as fingerprints, like a string of tiny water droplets. Many photons transmitted in parallel will change direction and increase dispersion after passing through these "water droplets". Take a look at this optical fiber on the screen. It is 217 meters long and does not exceed the standard limit of 300 meters. The total attenuation value is 2.15 decibels, and the loss has no excess difference. I think it should be no problem to run 10 gigabytes, but not after 10 gigabytes of equipment is added. Or the bit error rate is very high. At this time, the problem is to take the time to try to change the optical module and equipment first. If it doesn't work, you wonder, why is there something wrong with it? The length did not exceed, the attenuation did not exceed, at this time began to pay attention to this problem. We call this problem "upgrading pains", especially a typical problem in the transition from 1 trillion to 10 trillion. You are in the test, at 107 meters to look for, first, clean, most of the time will be fine. Second, the connector may need to be replaced or the optical fiber may have to be remelted.

How to measure high-density optical fiber? Now that there are more MPO, we suggest to choose the adjusted method B. However, the connection and connection for testing needs to be provided by the manufacturer or the user. The first method is to test the jumper with SC-MPO. This jumper is SC at one end, MPO at the other end, and the benchmark is set with a MPO coupler in the middle. When testing, follow the third picture. The second way is to use the penultimate graph method to set the benchmark, which will use the MPO jumper. When testing, follow the diagram below it. This picture shows that the connector uses a single needle test head, and the end connected to the MPO needs to be made into a single needle, which can be independently inserted into any MPO fiber needle during the test. But this requires high manufacturing precision, which is a challenge for manufacturers. Another method is relatively easy: make some transfer compensation lines before doing it, which requires that the calibration error of each compensation line should not exceed 0.1 decibels (pre-check to pass).

With regard to the high-speed optical fiber testing in ordinary networks, that is, non-data centers, due to the limited investment in equipment, optical fiber connectors are usually not MPO, and the general inspection method is to introduce some standard OTDR tests. TSB140 default values can be used for quality determination-although these default parameters may be used less because of its conservative requirements for ordinary networks. Therefore, in addition, some suggestions are provided to some demanding users, because the general default connector has a minimum loss of 0.75dB, which allows you to customize it, because TSB140 is an open standard, users can reduce the loss requirements of joints and fusion points to 0.3,0.1dB.

Let's talk about housing. Housing is now relatively neglected. I tested two high-end houses last week, and the price is very high. In fact, the testing standard of residential wiring, such as 15018, has introduced some relatively standard things, such as introducing the main wiring and secondary wiring structure, which is similar to the horizontal wiring of the original intelligent building. but in fact, the quality requirements are leaning up. There will be more test objects defined, such as ICT, BCT, and CCCB control. The measurement method used in control is not extensive in terms of comprehensive wiring, so how to carry out this test is still a question mark. A wide range of testing objects, such as we test on railway locomotives, they have done some modified test jumpers, requiring only 10 megabytes, or better if you can meet the Category 3 line standards.

Finally, what does the Fluke network do? First, focus on the media data guarantee. Second, focus on network quality assurance. Third, wireless network guarantee. Then there is performance evaluation, plus troubleshooting-these are Fluke networks. This is the end of my content. Thank you.

Mr. Yin Gang of Fluke Company of USA

2010 China's top ten wiring brands, glorious bloom! Http://network.51cto.com/network/cteam/ccb2010

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