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- 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
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