On Data Throughput in Structured Cabling Systems

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Cabling infrastructure providers are following KRONE’s lead regarding the importance of having the lowest bit error rate possible. This white paper confirms that zero bit error rate is a practical reality that Network managers can rely on. More and more network managers are demanding that their networks operate to their maximum potential, rather than merely operate as a standardscompliant solution. Downtime or a slowdown in network performance can be crippling to an organisation in today’s global e-commerce environment. The network cabling infrastructure must be able to support an enterprise’s increasing rates of data transmission now and in the future....

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Nội dung Text: On Data Throughput in Structured Cabling Systems

WHITE PAPER ZERO BIT ERROR RATE On Data Throughput in Structured Cabling Systems Released by KRONE Australia Asia Pacific Test Laboratory (Certified by Underwriters Laboratories) February, 2001
ZERO BIT ERROR RATE Cabling infrastructure providers are following KRONE’s lead regarding the importance of having the lowest bit error rate possible. This white paper confirms that zero bit error rate is a practical reality that Network managers can rely on. More and more network managers are demanding of the signal. Events such as noise, impulses due to that their networks operate to their maximum switching surge or lightning, transmission equipment potential, rather than merely operate as a standards- fault plus others can all cause a bit error (eg. it is the compliant solution. Downtime or a slowdown in reception of 0 when 1 was transmitted or vice versa). network performance can be crippling to an The Bit Error Rate (BER) is a measure of how often organisation in today’s global e-commerce these errors occur. environment. Statistical Method Some measurement techniques are based on statistical The network cabling infrastructure must be able to analysis which predict the number of bit errors with a support an enterprise’s increasing rates of data certain degree of accuracy using common statistical transmission now and in the future. It’s imperative distribution methods. For example: that mission-critical information which is transmitted in P (e)_ packages of bits is delivered immediately, without Log2M < Pb (e) < P (e) costly delays. Bit Error Rate (BER) testing is one way of measuring a network’s performance - of seeing how Pb(e) is bit error probability which equals BER. quickly and efficiently information is delivered from P(e) is the probability that a waveform is detected sender to receiver. Zero Bit Error Rate (ZBER) has been incorrectly. the goal that now is a practical reality, thanks to M is the number of discrete signal levels (eg 3 for KRONE’s TrueNet solution. PAM-3, 5 for PAM-5). However, controversy reigns in the cabling industry Practical Method today disputing the ability to actually measure an Although KRONE uses both statistical and practical absolute zero. Amid claims that ZBER is no more than methods, we put more emphasis on a new buzz-acronym and, therefore, cannot be the measurement of real errors as a way of achieved, this White Paper outlines KRONE’s understanding the nature of an error. Any modern methodology of testing for, achieving and, indeed, LAN hardware and network analysis software can guaranteeing Zero Bit Error Rate. perform this real physical measurement. WHAT THE STANDARDS SAY Practical measurement techniques use the cyclic The IEEE 802.3 Standard defines the lowest acceptable redundancy check (CRC) to determine actual bit error value for Bit Error Rate (BER) for 1000 Base-T as being failures in any period of time. 10-10. This BER limit is set for levels of line encoding using pulse amplitude modulation (PAM-5). This is the For example, there may be two CRC failures after encoding scheme for Gigabit Ethernet. running a system using PAM-5 encoding for, say, 100 hours. CRC uses a frame check sequence, developed WHAT IS BER? by the transmitter, that is checked by the receiver to A bit error occurs when the transmitted signal is see if it is valid or not. If it is not valid, because at corrupted by an event which changes the voltage level least one bit contains an error, the receiver rejects the
whole packet of data that may contain up to 1500 equipment available on the market such as Netcom bytes x 8 bits = 12,000 bits for an Ethernet Frame. Systems Smartbits SMB-2000, Vigilant Big Tangerine, This means that one bit error can cause up to 12,000 and Fluke DSP 4000. These tools are recognised as bits to be re-transmitted. the best by all international test laboratories such as The Tolly Group, BiCSi, Bell Laboratories, etc. WHAT IS A ZERO BIT ERROR RATE? In the example below, KRONE used Smartbits SMB- IEEE 802.3 defines the occurrence of errors at 10-10 as 2000 Signal Generators generating up to being its worst case. At this condition any bit errors 19 Gigabits of continuous traffic in both directions at which may exist do not degrade the performance of once. A Pentium 200MHz laptop computer was used the network because all network hardware and to monitor the traffic for four days while the site was software is built to meet this condition. Therefore, any influenced by neighbouring external noise sources. noise present at this condition will be insufficient to There were zero delivery errors. alter the bit value at the receiver and cause an error. KRONE went even further, analysing network latency using advanced Netcom SmartFlow v. 1.14 network analysis software generating different groups KRONE has selected a level 100 times lower than the of data streams. worst case in the Standard and has called this BER condition of 10-12 as ZERO BIT ERROR RATE. Zero Bit Error Rate (ZBER) means less than one error in a million-million bits. WHAT KRONE DOES In-House Testing We consider field network testing to be the most accurate way to correlate theoretical base to real world performance. To do this, we measure the product performance in the laboratory under severe noise conditions (simulating worst case real life environment) and then we test the installed cabling systems at the customer’s site to verify the laboratory performance in The results showed that during the tests no frames were no-load and live network conditions (eg the network is lost on KRONE’s TrueNet™ cabling system. fully functional). Field Testing TrueNet C6T For field testing of commercial and industrial sites, KRONE Platinum Solution KRONE uses an advanced 24-port Vigilant Network Test 1 Test 2 Test 3 Gigabit Card No 01 GX-1420B 01 GX-1420B 01 GX-1420B Monitor to evaluate the health and integrity of a Tx Frames 237,644,979 13,115,406 11,393,017 customer’s structured cabling system on a Rx Frames 233,998,500 12,648,131 11,631,058 Rx Bits 14,975,904,000 19,199,862,858 17,655,946,044 continuous basis. From this testing, measurements Rx Triggers 0 0 0 of impedance versus distance and frequency are CRC Errors 0 0 0 Over Size 0 0 0 made, finding the impedance mismatches and Frag/Under Size 0 0 0 discontinuities in a network channel that cause BER 0 0 0 network traffic to slow down. When testing, KRONE uses the latest test technologies We found that impedance mismatch was the main and the most sophisticated digital measurement factor that caused performance loss in
a structured cabling system. TIA/EAI-568A standard Most impedance mismatch problems happen in the specifies the impedance variation to be +/-15 Ohms cross-connect patch cord in the closet, the but KRONE’s TrueNet™ Cabling System goes even consolidation point, and the connectors at the further, restricting it to ±3 Ohms. telecommunications outlet. The first few metres on The test equipment captures noise, interference and the graph relate to the temporary use of the cross-talk events in the network and analyses the injecting patch cord - which is the connection effect they have on performance. From these between the tester and the cable run. The rest of measure-ments we have been able to verify that the graph shows that the cable run and all correctly installed TrueNet™ Cabling Systems have components are within ±3 Ohms resulting in impedance which is within ±3 Ohms throughout negligible impedance mismatches that will not the cabling channel. cause bit errors and thereby data retransmissions. The graph below shows test results from a TrueNet THE RESULT cable run in a customer’s structured cabling system. Both in-house testing and on-site testing confirm KRONE’s technical approach to proving the feasibility of achieving Zero Bit Error Rates is correct. More importantly, KRONE customers confirm that Zero Bit Injecting patchcord Cable run Error Rates are achievable on their installed sites. Because KRONE components are tuned to remove impedance mismatches, the TrueNet™ Cabling System does perform with a bit error rate lower than 10-12. This well exceeds the standards requirements of 10-10. Therefore, KRONE can offer a 5-year “ZBER” throughput warranty to sites that install a KRONE TrueNet™ structured cabling system. Berkeley Vale, Australia February, 2001 By Boris Torban Peter Meijer Telecommunications Engineer Technical Training Manager KRONE (Australia) Holdings Pty Limited KRONE (Australia) Holdings Pty Limited For further information please contact: KRONE (N.Z.) Technique Limited KRONE (Australia) Holdings Pty Limited PO Box 38-177 PO Box 335, Wyong NSW 2259 Wellington Mail Centre 2 Hereford Street, Berkeley Vale NSW 2261 Wellington, New Zealand Tel: 02 4388 4422 Tel: 0800 657 663 Fax: 02 4388 4499 Fax: 0800 355 100 Email: kronehlp@krone.com.au Email: sales@krone.co.nz Web: www.krone.com.au 5549 10/01