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The Science of ValidatorTM Over the course of the past few months, we have had dozens of conversations with customers, manufacturers, industry magazines, technical committee members, and just interested potential end users about how Validator works, what it is measuring and how it correlates to what is already out there, etc., etc., etc. I have piecemealed a lot of these discussions into some communications to the field. Now I want to update and clarify some elements of the Validator story and add some things that are more current than what you have seen thus far. This paper will help potential customers understand what the Validator is and how it works. The main question we are asked about Validator is whether it is “really” a Certifier. This can be answered with a resounding YES. Validator is a Certifier. It certifies cable runs against TIA568 Interconnect Standards and with TIA568 noise and delay measurements. In addition it does an additional test called BERT that will be explained in this paper. We feel that Validator not only complies with TIA5689, but actually goes one step further in proving the actual capacity of CAT5, 5E and CAT6 network cables. History The original formation of the TIA568 committee was to codify and structure the proper way of installing data cable, so that it would work correctly and establish levels of performance that led to higher levels of measurement requirements. They called the cable levels “Categories” and this led to CAT5, CAT5E, CAT6, etc. At the time of the initial formation of the committee, there was no real concurrence as to where the network architecture was going to land. It only became clear after IEEE adopted specifications on Ethernet systems (IEEE802.3) and defined speed standards as 10Mbit, 100Mbit, and Gigabit. So, the initial TIA568 committee members decided on physical parameters and measurements that were linked to frequency signals that would infer performance against a set standard of bandwidth, because there was no “digital” profile on what network speeds or data requirements were going to be necessary. That is why everything in TIA568 is anchored in frequency instead of speed. Speed standards did not exist when the spec was first formulated. This is no surprise. since most of the testing metrics in TIA 568 were adopted as much as 15 years ago! Gigabit Ethernet upset this applecart, because it uses all four pairs simultaneously and created conditions that needed further “refinement” for test that resulted in the creation of a measurement for Power Sum Near and Far End Crosstalk (PSNEXT and PSFENEXT). This despite Gigabit Ethernet having the same frequency spectrum or content as the 100Mbit Ethernet system. In other words, the only way to help measure a noise potential in Gigabit Ethernet systems was by looking at another noise factor that added up the other three pairs influence under test instead of only one pair’s influence as on 100Mbit. Frequency measurement techniques required this added level of testing complexity for TIA568 to be relevant for Gigabit Ethernet. All of these frequency measurements were attempts to match the medium (cable) data carrying capability and infer what would happen at a given speed. No empirical true demonstrations of error free transmissions were even contemplated. Validator vs. Traditional Certifiers So what is the basic difference between the Validator certifier and traditional certifiers from Fluke and Ideal Industries? It is that the traditional certifier uses frequency sweep signals to measure likely conditions for failure on a cable and measures the results of these signals against a set of pre-determined limits on each measurement (the metrics of TIA568). The Validator uses digital signal generation to measure the actual noise levels on a cable run, Signal-to-Noise ratio (SNR) and adds the BERT test as a demonstration of error free transmissions of actual digital data over that line. In effect, our BERT test is an advanced version of the PSFENEXT measurement mentioned in TIA568. It sees actual data flow rates from BOTH ends of the cable run while Far End NEXT and Power Sum NEXT try to infer data carrying capability by simulation with transient frequency signals. The BERT result is a true measurement of real data flow and error levels and with this in mind it is easy to see that the Validator does match all of TIA568 test specifications, since the SNR contains all the noise measurements of TIA568 and the SKEW measurement is the same. We just do the tests with a different method. In fact, we maintain that the digital BERT test is a more accurate measurement of return data loss than the FENEXT and PSNEXT tests called for in TIA568. What does the Signal-to-Noise Ratio shown in Validator test results represent? Remember that this is a compilation of measurements off of the Gigabit Ethernet Transceiver. They include Return Loss, Attenuation, NEXT and Channel Response from all four pairs which is necessary to measure noise for Gigabit. The PASS/FAIL level of 20dB is a correlation off of the Ethernet Transceiver chip which was arrived at by analyzing cable failures in all types of environments and conditions. This chip was tested and measurements correlated by the University of New Hampshire Commercial Network Test Laboratory that is the gold standard for all network equipment manufacturers. We took the same PASS/FAIL levels from these tests and applied them to the software/firmware programs we created for the Validator. The correlation of data is every bit as valid and accurate as a $6,000 traditional certifier. Remember that the higher the SNR is the better the level of signal over the ambient noise on the line. You might think of it as the bars on a cell phone, the more bars the higher the signal strength. The same goes for the SNR measurement that shows up on the results screen of a cable test. We put the upper limit as 30dB that is an almost perfect propagation level for any type of data cable. This limit is displayed at the top of the SNR bar on the Test Results screen at every cable test. Our SKEW measurement is a way of showing if there is any delay on any pair in getting data to the other end at a different rate than the other pairs. SKEW causes loss or dropped data bits and can “confuse” network equipment. SKEW is measured in nanoseconds (ns) and a SKEW of more than 45 nanoseconds is bad. This is the same level of failure that is called for in TIA568/570. Both of these measurements, SKEW and SNR, have roots in TIA568. They provide the data for a first look at a cable and let’s us know if some physical impediment exists before any data can flow. Noise and signal delays can usually be traced to bad terminations or improper cable installation. Even poor quality components will cause failures. However we use these measurements as only a tripwire. The BERT test is the real test of cable functionality. BERT itself was a bit of trick for us to adapt to the Validator. We had to obtain and test every PHY or Physical Interface Link on the market today to make sure that our return information would match acceptance formats for these PHY chips on various brands of network equipment, routers, switches, hubs, etc. We did this to make sure that when we certified a cable at Gigabit speeds the data transference rate that was measured would work with installed equipment, no matter who the manufacturer is. This was possible, since there is only about a half dozen PHY chip manufacturers in the world. Our innovative and technologically advanced approach shows that this is an entirely different way of addressing the need to determine whether or not a cable can carry data at a given speed. Traditional certifiers infer and we use actual conditions that interface with actual network components. It is that simple. The Belief vs. Science – Superstition vs. Empirical Proof Despite the legitimacy of the Validator science in certifying a cable’s capability, the fact is that TIA568 is taken as the only “standard” by much of the BICSI cabling industry. The logic here is that there is no competing “spec” to refer to. However, the truth is that IEEE802.3 defines a speed specification and an error rate that has to be matched for an Ethernet system to be able to transfer data at given speeds. That is why we refer to IEEE802.3. It discusses actual Ethernet needs, not cable potentials as TIA568/570 do. The trouble is that some people believe TIA568 is the only standard and that IEEE is just a guideline. This belief is rooted in years of the traditional certifier companies beating the drums on all the committees they sit on and grinding out PR, technical papers, and articles in industry journals. It is this preaching, and the lack of a competing idea that has lent such credibility to TIA568 and is why we are asked about its role in Validator’s measurements. TIA568 has done its job. It has shown the way on how to install and test cables for networks. However the technology has changed dramatically in the 15years, since TIA568 was first envisioned. Digital technology now allows each cable installer to actually put live digital data packets down a cable run and see exactly how real life data will flow and at what speed. This was simply not thought of, nor possible, when TIA568 was first constructed. Speed standard testing that we are doing with Validator will become more and more adopted as the true way to see how a cable will work in a real network condition and the TIA568 “Standard” will be just another set of specifications to be used as a guideline. The standard Ethernet systems, 10Mbit, 100Mbit, and 1 Gigabit are the only ones in use today for practically every network in existence. They are all well defined and operate at set speeds. Every piece of network equipment manufactured is tuned to these speeds. No matter how much “headroom” or how many frequency sweeps are measured a cable is only going to carry data at a given rate, 10Mbit, 100Mbit, or Gigabit depending on the Ethernet equipment attached. It can’t be any better than that. Testing for anything more than 1 Gigabit Speed capability, at this time, is a waste of customer money and time. The traditional certifier manufacturers know that questions are raised about the “natural” limits of the Ethernet speed standard and constantly search for and promote “future proofing.” To do this they have to come up with new performance levels. Thus, the beginning of the talk about 10 Gigabit over copper and the need to reach ever higher frequency levels of test. The truth is, as most network scientists know, 10 Gigabit will not be able to get out of the labs and data centers for the foreseeable future, since there are no applications where it is necessary, nor copper cable or components available to carry 10Gigabits more than 10 meters. However by promoting the possibility of this new speed limit there is hope to justify the need for headroom and all the other possible measurements for something that doesn’t now exist. However it helps to sell more traditional certifiers or “new” versions of these same devices and obsoletes all the existing field equipment now in use. It may be a great marketing tool but is definitely not in the best interests of the networking world in general. Take the creation of Level I, II, and III ratings which are simply levels of accuracy of the frequency oriented tests done by traditional certifiers. This is pure marketing one-upmanship and has nothing to do with the performance of the network cabling on an empirical level. It is just another method of cloaking the entire process in some form of mythical cloud or belief. Accuracy of tests should not be even in question and are not when it comes to Validator. We certify the Speed and Performance of the cable without reservation or needing to turn to excuses due to accuracy of our equipment. How many of us are worried about the “accuracy” of our cell phones or have to send them in once a year for “calibration” like what has to be done on a traditional certifier? Digital technology has put an end to this. Conclusion The best analogy we can give is that a traditional certifier is like estimating the time it will take to drive between two cities by analyzing the road, looking at the weather report, and listening to the traffic condition on the radio. Validator actually puts a car on the road and drives to the designated city and reports back on how long it ACTUALLY took. It is real time and real data. No estimates, no inferences, no guesses. The landscape of certification is changing. With the changes in digital technology, it is inevitable! As more and more installers and network owners understand the need for real data transference (BERT) to determine cable carrying capability they will ask questions about the relevancy and accuracy of many of the TIA568/570 tests. Validator uses the latest and most advanced methods of testing network cables and provides the most accurate information possible in determining cable capabilities up to 1 Gigabit in speed. No equivocation, no apologies. Validator has created a superior way to tell how cable runs will work in actual network conditions. It is the beginning of a new era in network testing and will help network installers and owners have increased confidence that installed cables will work correctly and without trouble. Much of the mythology of certification has been created to sow fear instead of striving to enlighten. Fear of not meeting cable manufacturers guarantee schemes, fear of some liability due to a cable that does not work as the network owner desires, fear of not being able to “guarantee” a job’s worth. We reject this shabby and purposely deceptive method of marketing. Validator is not here to make its customers afraid. It is here to bring hope for an easier and more effective way to test network and other forms of cables that takes advantage of the latest in digital technology. There is enough fear in the world. We don’t need it in testing. We intend to upgrade functionality and capabilities of Validator over and over again to give our customers not only the most advanced certifier on the market but the most flexible and long lasting one as well. Look for these upgrades and new functionality for Validator in coming months. It is our way of keeping it current and of the best possible help to our customers. you can find it here