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Schneider Electric
Network Certification Services
Technical Services Report
Month / Date, Year
Prepared for:
Company Name
Facility Description
City, State
Meeting Dates:
Attending
Schneider Automation Inc
b
One High Street
North Andover, MA USA
01845
Tel. (1) 978-794-0800
Fax (1) 978-975-9400
www.schneiderautomation.com
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Table of Contents
Executive Summary
3
Primary Technical Objective
3
SCADA Issue
6
Customer Action Items
7
Network Certification Services Recommendations
7
Inter-Switch Links
10
Switch Inventory
10
Discovered Topology Schematic
11
Cable Test Results
11
Switch Port Schedule
13
Contact
15
Glossary of Terms and Test Parameters
16
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Executive Summary

This case illustrates an actual customer problem experienced by a food processor and the
steps Schneider Electric - Network Certification Services (NCS) took to resolve the problem.
In addition, the NCS Engineer found additional issues that when addressed, would benefit the
customer. Those benefits included increased performance, reliability and management.
Our customer was experiencing repeated losses of communication with a PLC which is documented in
our Schneider Technical Support case tracking database. This PLC was equipped with a Quantum NOE
771-00 Ethernet module, at the current firmware revision and located in the Canning facility. The module
would appear to drop all network communications at random. Additional Logic was then installed in the
affected controller to remedy the problem. However, the communication interruptions persisted and the
customer was concerned that production could be adversely affected. A Network Engineer from the NCS
team was sent to visit the customer and determine the root cause and secure a remedy.
The customer dealt with this problem for a year without finding a solution. Our customer had also brought
in outside network integrators for a fee to analyze the network. Though a substantial report was
produced, there was no root cause identification, or solution found to the problem.
After onsite analysis using a variety of NCS test tools and methods, the root cause was determined to be
a faulty Ethernet patch cord connecting the module to the Ethernet switch at a patch panel located in a
MCC cabinet. This was not uncovered earlier because the affected switch port paper inventory did not
reveal the actual location of the NOE 771-00 connection. The patch cord was replaced and no such
communications loss has occurred since that replacement.
However, during the course of routine examination of our customers network, several issues were
uncovered that could improve the resilience of the customers network. These issues are unrelated to the
principal objective of the NCS visit, yet could improve the overall performance and stability of their control
network. These uncovered items are included in this report in the section Customer Action Items on page
6 and in the section Network Certification Services Recommendations on page 7. Optionally, the NCS
team can provide assistance with the items and recommendations outlined. Review the Contact section
on page 15 at the end of this document for additional information, and to obtain a proposal for additional
services.
Interrogating a selection of available network switches within the control subnet assembled a Switch Port
Schedule on page 13. This may help our customer reconcile any changes to their existing port schedule
due to any undocumented moves, adds, or changes.
Primary Technical Objective

This section outlines a description of the reported problem and the technology tools and
approach used by the NCS Engineer to diagnose the issue.
The problem was first described as a communications issue between the SCADA server the Quantum
NOE 771-00 at software revision 2.10 in the Canning facility. Interruptions in communication caused a
loss of operator control in the Canning facility packaging line. The packaging line moves completed
product from the pressure cookers to the area where the pouches are unloaded from the processing
cassettes to packaging for shipment. Two PLC’s, coordinate with each other for product location and
handling for the conveyor and shuttle systems servicing operations from vacuum processing to
packaging.
3
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One of two SCADA servers are Microsoft Windows 2000 Server SCADA that communicate with each
PLC and then serve as a proxy to furnish the data read from the PLC to the clients, which are operator
control terminals. The SCADA server then furnishes the updated register and coil data to multiple client
PC operator terminals. This architecture decreases the number of direct ModbusTCP client connections
to the PLC’s by coalescing communications from having multiple operator terminals query the PLC’s to
instead have two SCADA Servers query the PLC’s and proxy the data to the multiple operator terminals.
The result is a dramatic increase in operator terminal performance and a reduced communications
burden on the PLC’s by limiting the number of ModbusTCP server connections at the PLC. To illustrate,
instead of each PLC communicating with up to 15 PC operator terminals, each requesting the same or
similar data, the PLC’s now would communicate with two SCADA servers. The operator terminals then
draw the data from the SCADA servers. This offers a significant performance gain in terminal
responsiveness and boost in communications efficiency.
The SCADA servers were designed to provide redundancy for each other. Should communications be
interrupted to the primary SCADA server, the system could transfer communications to the secondary
SCADA server. However if communications were lost to a PLC (as was the case) the updated positioning
data would not be obtained. This could lead to problems as the operator terminals would not be able to
ascertain the quantity and location of product queued for packaging.
The NOE 771 00 module in question was replaced twice to rule out any possibility of hardware failure.
Reported communications failures appeared to be random but reportedly seemed to occur over a
weekend. However, it may be the case that the failure occurred during the weekend and was discovered
by the operator upon return to the plant. The plant operates on a 24x5 schedule and staff may not be
present to respond to the failure until startup at the beginning of the work-week.
Efforts prior to the site visit included installing “Reset Logic” in the CPU of the affected NOE module. The
logic would monitor Ethernet Transmit (TX) interrupt activity by comparing activity over a 10-second
period. If there was no change in the TX interrupt value over that sample period, it would assume that
transmit communications ceased and then would trigger an additional MBP_MSTR Option Module Reset
function block to automatically reset the NOE without operator intervention. However, communications
would be lost to this particular NOE and the tested logic would not trigger. This logic is meant to
circumvent temporary network disturbances such as broadcast storms, switch fabric interruptions and
cabling faults. The failure of this logic to respond in this circumstance prompted action by Schneider
Electric NCS team.
A methodology of installing a Protocol Analyzer and a switch setup mirroring the traffic on the affected
port to the Analyzer installed on the switch was used to study the ModbusTCP communications format,
response times and peer patterns, as well as trap an actual failure event and any events that may
precede the reported failure. The Ethernet switch MAC address tables and port statistics were also
studied. A resulting analysis of the switch address tables revealed that the location of the NOE module
did not agree with the paper inventory, likely due to an undocumented move.
The protocol analyzer successfully captured a failure event consistent with the report, and analysis
revealed that the NOE did in fact stop communicating. We received a warning that communications were
lost in the Control Room via a SCADA operator terminal and immediately attempted to “ping” the module
for a reply. The module did not respond. We then responded to the module location, secured the protocol
analyzer trace files and interviewed the first responder that had noted the error and reseated the RJ-45
connector on the NOE module.
4
s
The first responder found that the NOE was still actively flashing the TX and RX LED’s though there was
an interruption in communications. This suggests continued communications in the module, though there
was no Error or Fault LED indicator, and the module was unreachable over the network.
Suspicion that the cabling may play a role in this was deduced by theorizing that a single conductor or
pair of conductors transmitting from the switch to the NOE may be fine, but that a conductor or pair
transmitting from the NOE to the switch may not. As the NOE is a DTE device and the switch is a DCE
device, the transmit pair on the NOE connects to the corresponding receive pair on the switch.
A review of the Ethernet statistics page on the NOE revealed zero errors and normal operation. However,
the receive port statistics on the 3Com switch indicated FCS (Frame Check Sequence), errors. The FCS
is a 4 byte CRC added to the MAC layer at OSI Layer 2 Ethernet frame to ensure bit integrity that the
message is received exactly as it is sent. FCS errors in 100BaseTX environments indicate either of two
conditions; that the frame was damaged in transit to the receiver, or that the transmitter and receiver are
communicating with mis-matched duplex settings. Duplex operation was found to be properly matched at
each end by observing LED status on the switch and NOE, and by confirming the switch duplex through
the administrator console. Therefore, the logical conclusion suggested a faulty receive pair on the switch,
or possibly a faulty physical port on the switch.
A plan was assembled to replace the patch cord during production silence and move the NOE 771 00
connection to an open and available switch port to rule out both circumstances. The result was
successful.
Verification of the uninstalled NOE module patch cable revealed the cable was incompatible with 100Mbs
IEEE 802.3u 100BaseTX Full Duplex Ethernet communications. NCS references the use of IEEE 802.3u
“Fast Ethernet” 100BaseTX Ethernet cabling to be consistent with industry test specification TIA/EIA-A or
B. A time was arranged to replace the patch cord so as not to impact production. This occurred during a
shift change when the product shuttle/conveyor in the package area had cleared processed products for
packaging. At this time customer product was unaffected by the PLC to PLC coordinated communications
due to an empty queue. The test results on the patch cord in question are attached to this report in the
section entitled Cable Test Results on page 11.
Each Ethernet DCE to DTE cable end (between a switch and an NOE module) has 2 pair of conductors
Transmit (TX+/-) and Receive (RX+/-). At one end, the TX pair connects to the RX pair on the other end.
If in transit from one device to another, a frame is damaged, this event is not transferred to the transmitter
because the CSMA/CD (Carrier Sense Multiple Access/Collision Detection), algorithm is disabled in
100BaseTX Full Duplex operation. Therefore the sender has no knowledge that the frame sent is corrupt.
The function of recovering from this is managed by the application layer ordering a retransmission of the
TCP segment. However, in this event, all subsequent retransmission attempts, the Ethernet frames were
subsequently corrupted. This results in the TX Interrupt counter on the NOE continuing to increment,
while the switch records FCS errors and properly rejects the frames at the port interface as invalid.
This explains why the MBP_MSTR Reset Logic, installed in the controller, did not trigger the Option
Module Reset. Packets were leaving the NOE correctly but were received as FCS errors on the 3Com
SuperStack 3 switch port. This condition also caused the switch not to forward the frame to the “mirrored”
port where the protocol analyzer was capturing traffic and therefore the NOE appeared on the protocol
analyzer to cease communications.
The solution was obtaining a status of the Ethernet switch port statistics before and after the event.
Before and during normal operation the FCS error statistics on the affected port remained at 25,014.
However, after the captured event, the number increased by 1,100. This indicated that the NOE module
was unaware of any error condition yet the switch was dropping each frame sent by the NOE.
5
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
(Note that a complete system “snapshot” of NOE module memory, process buffers, TCP/UDP activity and
corresponding switch port statistics were captured at the arrival of the NCS Engineer. Over 20 data points
were collected on the NOE and a complete download of configuration/memory/port statistics from the
switches. These data points were continually monitored, stored, and continually referenced for changes).
Because the frames were dropped by the ingress port of the switch on which the NOE 771 00 module
was attached, they were not forwarded to peer hosts that were seeking to restore communications via
ARP Requests (IP Address Resolution Protocol), nor were the damaged frames forwarded to the egress
“mirrored” Analyzer port. Therefore, the NOE appeared to stop communicating, when it actually was
communicating.
Such a condition would also not generate an ICMP Reply message (Ping), in response to an ICMP
Request as was tested during a communications fault event.
SCADA Issue

This section describes how the NCS Engineer separated the SCADA issue from the Ethernet
module issue. This allowed in-depth examination of each.
Primary and secondary SCADA servers would read from the PLC to accumulate data for operator
terminal requests. At random intervals, the primary SCADA server would indicate a crash of the driver
service. Clients would then transfer to the secondary SCADA server as a backup. Actions taken to try and
identify what may be causing the primary SCADA server to crash included:





Separation of the server in the cabinet to improve cooling and to avoid Pentium 4 CPU’s being
stacked in a production area non-ventilated cabinet
Command line interrogation of all system statistics and capture to a file
Removal of unnecessary Windows 2000 services such as Web services, etc.
Review of the memory usage, kernel and process thread statistics
Analysis of protocol trace files via port mirroring for any improperly formatted ModbusTCP messages
The driver service crash on the Windows 2000 primary SCADA server was identified by the SCADA OEM
Technical Support group as resulting from an “improperly formatted Modbus message”. However,
analysis has not located such a message in an event captured by the NCS protocol analyzer.
Communications peers were PLC’s on TCP port 502, and PC clients at higher number TCP ports (over
port number 1024). A communications matrix and response time analysis revealed that delays increased
prior to a driver crash. Also, the number or TCP/UDP sessions analyzed ranged from 100 to 200 at the
primary SCADA server. Increasing the number of such connections, and the message sizes requested,
can deplete the available RX buffer memory to service each connection within an acceptable response
window. Slicing the available buffer memory into increasing smaller segments to service each connection
could theoretically cause overrun of the RX buffers. Incidents that may precipitate such an incident
include TCP/IP/WinSock distractions such as excessive IP broadcast or UDP NetBIOS traffic. Such
events were recorded when peer PC’s requested updated browse lists from an unresponsive Domain or
Workgroup NetBIOS Master Browser or Domain Controller. Repetitive requests for a known Domain
Controller as well as “Browser Election Force” NetBIOS packets were also recorded surrounding the
driver service failure event. A remedy indicated in Network Certification Services Recommendations on
page 7 suggests that the customer refine a host name resolution solution.
6
s
SCADA OEM representatives visited the site and removed the hard disk from the customers PC for
further study. The OEM is also in the process of developing and deploying an updated driver to address
the problem, though there is no direct correlation between the server failure event and the promised
improvements in the updated software release.
Customer Action Items

The NCS Engineer uncovered the following areas requiring immediate corrective action.
Though the customer was advised to implement these changes, the NCS team can be
contracted to implement the corrective action plan.
NCS recommends that the customer investigate the following items discovered during routine analysis of
their network. It is likely that such issues could prevent them from achieving maximum performance from
their network.

Switches Development, Canning facility, and Spare do not properly report Duplex settings. This could
be related to faulty firmware or configuration. Proper information in this regard is essential.

Some devices report 10 MB/s Half-Duplex connections. Refer to Inventory section. Network Adapters
capable of Full Duplex operation will significantly out-perform collision-based half-duplex systems.

Check reported mis-configuration between switches. CORE_2 port 35 is connected to Boiler port 27.
The CORE_2 port 35 is configured at Half Duplex, and the Boiler port 27 is configured for Full Duplex.
Impact is reported Frame Check Sequence, Alignment, Fragment and Collision errors. The segment
may operate, but at significantly reduced efficiency and slower response times.

Configure an IP Address on the second the SQL server network adapter. This SQL Server has two
network adapters. However, only one of the adapters is configured with a proper IP address. The
second adapter is configured for DHCP, but since no DHCP server exists on the subnet, it defaults to
169.254.155.42. The Mfr. OUI (Organizationally Unique Identifier), MAC prefix of the adapters
indicates that they are from Compaq. Check with HP/Compaq to see if perhaps your adapters can be
teamed together for load balancing and fault tolerance. It may also be a wise to check for current
version of SoftPaq’s and ROMPaq’s for your Proliant series servers as well.

Check speed and duplex settings on any intermediate devices such as transceivers. Duplex can be
mis-matched by proxy. For illustration, on side of the transceiver can be configured at maximum
speed and duplex, however, the other side could be not optimally configured. Depending on the
buffer memory available in the transceiver, this could result in a significant bottleneck and potentially
dropped Ethernet frames.
Recommendations

The NCS Engineer followed up with Best Practice recommendations to further improve the
performance and stability of our customer’s network.
The following bulleted items may offer additional stability and functionality on the customer network as
well as speed troubleshooting and problem isolation. Many cover routine best practice areas for network
maintenance.
7
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
Updated documentation of cabling and switch port population
While a paper inventory of switch port assignments is helpful, it may be best cross-checked with either
manual interrogation of the switch Address Tables, or through scheduled discovery using electronic
SNMP tools. Note that it would be advisable to perform SNMP discoveries during non-production hours
so that critical communications and response times are not impacted by the SNMP queries.

Enable and Configure the Spanning Tree Protocol on all Switches
The Spanning Tree protocol can prevent network loops. I noted that Spanning Tree appeared disabled in
many of the switches I interrogated; however, there was an instance of some Bridge Protocol Data Unit
(BPDU) traffic indicating that STP is enabled on some links. The BPDU’s are multicast to neighboring
switches to provide topology change information. This measure could also be potentially architected into
a redundant switch solution that does not require human intervention.

Implement periodic physical maintenance of switches
Include with this dust removal and ensuring that there is adequate cooling and ventilation sufficient within
the switch OEM published limits for warranty integrity. One of the switches in the core was indicating that
it was over-temperature. We opened the door on the cabinet rack to allow for additional air circulation. It
may also be advisable to provide more space between the rack mounted components, and/or to install
equipment fans on the top of the rack. Check the rack documentation for knockout panels to see if this is
possible.

Update firmware on Switches
The switches controlling the production network range in age from 1 to 4 years old and appear to have
the original firmware installed as when shipped. It makes sense to maintain current firmware if there is
derived benefit. Be sure to consult the OEM ReadMe with any released firmware upgrade. Upgraded
firmware usually addresses any known issues with the equipment and also may offer additional features
or enhanced support for new standards.

Updated PC NIC drivers
Updating drivers for the PC/Server network interface cards may allow additional features to be controlled
by the operator. One of the key features that may help improve response time is to increase the Receive
Buffers on the network adapter. This will allow for more memory to be devoted to each connection to the
PC. I noted that in the case of the primary SCADA server, there were over 100 TCP connections open. If
the receive buffer memory is insufficient to service the incoming requests, those requests could be
dropped. This may be consistent with the communications time-out by other PC”s trying to reach the
primary SCADA server though the primary SCADA server continues to operate.

Implement Host Name Resolution Services
Much of the remaining broadcast traffic is due to queries for NetBIOS services. Implementing Windows
Internet Name Services, (WINS), DNS, Dynamic DNS, or local host files would reduce the number of
queries generated. Each time a PC browses the network (Network Neighborhood), a request is issued for
the Domain Master browser. This NetBIOS over IP broadcast can reach thresholds where it could
interrupt or delay PLC and PC communications. This activity also expenses critical RX buffers on RealTime Ethernet devices.
8
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
Improved Cable Management
NCS suggests adding cable management rack components to switch and patch panels. These products
are one or more rack units high and can more effectively keep patch cables secure while ensuring cable
clearance per the industry specification. The wiring specification for 100Mbs Full Duplex Ethernet is
based upon TIA/EIA 568-A/B. The specification denotes minimum bend radii, and horizontal/vertical cable
handling procedures to maintain the integrity of the cable plant infrastructure. It should be noted as well
that Shielded Twisted Pair (STP), cabling could be beneficial in industrial applications. Particularly if there
is even a slight difference in ground potential between MCC’s where the horizontal cable is run. All of
Schneider Electric Transparent Ready products support the use of a shielded RJ-45 connector. Cable
management panels should be 1U (1 rack unit), per 24 ports per each port. (Example: A 24 port switch
and a 24 port corresponding patch panel would require 2 units of cable management)

Backup Switch Images
Consider using a TFTP server to store configuration files from switches should replacement become
necessary. Note that the replacement must be the same part number as the failed unit. If different units
are used, maintain a parallel configuration. Also remember to upgrade standby units as necessary when
upgrading production units.

Test and Certify Ethernet Patch Cables
Though the installer inspected and tested the horizontal cabling, it may be beneficial to test and verify the
patch cable used to connect the field devices. Particularly in the case of PC”s, patch cords can be
damaged through movement and could impair error free operation. Many switch ports recorded errors in
the 48 hour period after the counters were zeroed during a weekend reset. This indicates that some links
are operating continually with errors. Eliminating the root causes of these errors will improve reliability,
decrease latency and provide deterministic response times. Cable plant testing services are available
through Schneider Electric Network Certification Services. Refer to the Contact section on page 15 of this
document for additional information. Note as well the electrical differences when interconnecting
DCE/DTE devices located in MCC”s that may be different electrical ground potentials when using
conductive media. The preferred method is to have shielded cabling terminated in “biscuit” jacks to isolate
electrical interference. Lastly, the use of shielded patch cables is preferred.

Investigate Redundancy Options
The customer currently maintains “hot spare” switches at each switch location, along with “dark fiber”
spares. However, recovery of that segment after a failure requires network personnel to physically move
to the affected location and disconnect devices from the failed switch and then reconnect them to the
backup switch. While it is always preferable to have “hot spare” backup devices handy, it will most likely
result in some system downtime on that segment, and potentially a loss of product. Note that if the
backup units are also powered up 24x7, much like the devices that they are intended to replace so that it
is not dissimilar to actually being in service. Therefore, it is not outside the realm of possibility that the
backup unit may experience a failure before the primary unit, as they are both advancing towards the
MTBF equally. Also, with fans operating in a powered-up condition, the backup is drawing in dust and
other particulates at the same rate, and is also subject to overheating as a result. Note that the operating
temperature for the 3Com Ethernet switches is a maximum of 40 degrees C, or about 104 degrees F. It is
advised to install a thermometer inside the MCC’s where the switches are located to determine the actual
ambient temperature.
9
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Alternatives to providing fault tolerance that can continue essential communications in such a scenario
without human intervention can be discussed with Schneider Electric NCS. Please refer to the Contact
section on page 15 of this document for additional information.

Switch Status Lights
A question was raised regarding the status of the LED’s on the 3Com switches. Note that the first
resource for interpreting these is your switch documentation. However, 3Com reports link status using a
"P” and “S” status LED for each port. P indicates Packet traffic and S indicates status. A table for
reference follows:

LED
Color
Indication
Packet
Yellow or
Blinking
Packets are being Transmitted/Received
Status
Green
Off
Link detected
No link detected
Discovery tools used by the NCS Engineer produced an inventory of network devices and
interconnections that had not been documented This allows the customer to monitor specific
links for errors that may affect other network segments. This inventory also allows our
customer to update their paper inventory of devices, addresses and connections. Any links
that may be suspect were pointed out to the customer for further investigation.
Inter-switch Links
The following outlines the port schedule for switch interconnects.
FROM
Switch
CORE_1
CORE_1
CORE_1
CORE_1
CORE_1
CORE_1
CORE_1
CORE_2
Port
1
2
4
5
6
8
9
35
TO
Switch
MFG_1
Development
CORE_2
Canning facility
PKG1B
PKG2B
Packaging
Boiler
Port
47
38
49
37
49
49
37
27
IP Address
10.72.4.201
10.72.4.208
10.72.4.207
10.72.4.204
10.72.4.206
10.72.4.210
10.72.4.211
Model
SuperStack 2 9300
SuperStack 3 4300
SuperStack 2 3900
SuperStack 3 4300
SuperStack 2 3900
SuperStack 3 4300
SuperStack 3 4300
Speed/Duplex
1,000 Mbs
1,000 Mbs
1,000 Mbs
1,000 Mbs
1,000 Mbs
1,000 Mbs
1,000 Mbs
100 Mbs
Switch Inventory
Switch
CORE_1
MFG_1
Development
CORE_2
Canning facility
PKG1B
PKG2B
Software
2.00
1.10
2.00
1.10
3.00
1.10
1.10
10
s
Packaging
Boiler
Spare
Router
10.72.4.203
10.72.4.205
10.72.4.202
10.72.4.1
SuperStack 2 3900
SuperStack 2 1100
SuperStack 2 3900
DEC
3.00
2.00
3.00
Unk
Discovered Topology Schematic
Below is a schematic as represented by the switch tables that were inspected. This can be reconciled
with your existing inventory. Additionally there is a Inter-Switch Link schedule below which switch ports
interconnect the switches. Note that there are some devices which were unresponsive to discovery and
warrant addition configuration verification.
PKG1B
MFG_1
Development
Spare
Unknown
Router
Core_1
Packaging
PKG2B
CORE_2
Canning facility
Boiler

The NCS Engineer used an advanced Ethernet media testing tool to support the conclusion
drawn. This tool inspects cabling to the latest international standards.
Cable Test Results
The patch cable used in the problem area NOE 771-00 was tested using equipment certified to TIA/EIA
568-A/B. This test certifies Ethernet media to the accepted standards for 100 Mb/s Full Duplex operation
11
s
of 100BaseTX / IEEE 802.3u. Reseating this cable at the NOE end likely restored conductivity to pair 1-2
sufficient to restart communications. Vibration, temperature and time though likely degraded
communications periodically to again require such a reseating of the connector. The connector in
question did not have proper connector strain relief.
This test report illustrates that the Pair 1-2 failed Near End CrossTalk (a key requirement for Cat 5e), and
an open on pin 3. Pin 3 is the RX+ conductor on the switch side. A glossary of test criteria and terms can
be found in the section Glossary of Terms and Test Parameters beginning on page 16.
Note that the RED line shown in the graphs indicates the minimum acceptable
threshold per TIA/EIA 568A for IEEE 802.3u 100BaseTX operation
12
s
Switch Port Schedule
Below is the inventory as represented by the switch tables. It may be helpful to reconcile this switch MAC
Address list with existing paper and electronic inventory lists. Links that are 10Mb/s or set at Half Duplex
should warrant inspection and verification to determine if greater performance from these links can be
achieved. Also, devices labeled “unknown” should be inspected to determine the nature of their role on
the network.
Switch
Boiler
Boiler
Boiler
Canning
Canning
Canning
Canning
Canning
Canning
Canning
Canning
Canning
Canning
Canning
Canning
Canning
Canning
Cloud
Cloud
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
Port
MAC Address
3
5
13
1
3
4
5
6
9
10
13
14
15
16
19
23
28
Unk
Unk
1
2
4
5
6
7
8
9
12
14
15
16
17
18
19
21
22
23
24
00-c0-4f-79-f0-0a
00-c0-4f-79-a5-74
00-00-54-10-cb-fe
00-c0-4f-68-af-30
00-b0-d0-62-d3-27
00-c0-4f-6b-f1-d6
00-b0-d0-90-4a-6c
00-08-74-41-7c-90
00-c0-4f-a0-45-86
00-c0-4f-6b-e7-6c
00-c0-4f-a0-45-8c
00-c0-4f-68-fa-1a
00-00-54-10-86-a8
00-d0-c9-19-24-58
00-00-54-10-3f-ad
00-00-54-10-80-0c
00-00-54-10-3f-a5
00-c0-4f-6b-b2-15
00-b0-d0-60-4a-61
00-00-54-10-6b-b5
00-c0-4f-6b-f1-ab
00-06-5b-dd-a1-38
00-08-74-40-36-67
00-c0-4f-79-ec-e3
00-c0-4f-60-33-d4
00-c0-4f-79-ec-a9
00-c0-4f-68-b6-ef
00-c0-4f-60-35-06
00-06-5b-0e-af-ae
00-b0-d0-61-02-10
00-06-5b-0e-ca-ee
00-00-54-10-89-d0
00-c0-4f-ac-1d-e2
00-c0-4f-6b-b2-00
00-08-74-41-dc-4a
00-08-74-41-dc-44
00-00-54-10-89-d3
00-00-54-10-3f-d2
IP Address Speed Duplex
10.72.4.101
10.72.4.102
10.72.5.30
10.72.4.77
10.72.4.80
10.72.4.67
10.72.4.81
10.72.4.82
10.72.4.70
10.72.4.86
10.72.4.75
10.72.4.68
10.72.5.53
10.72.5.151
10.72.5.68
10.72.5.54
10.72.5.58
10.72.4.18
10.72.4.24
10.72.5.34
10.72.4.41
10.72.4.32
10.72.4.31
10.72.4.36
10.72.4.50
10.72.4.34
10.72.4.44
10.72.4.51
10.72.4.35
10.72.4.33
10.72.4.37
10.72.5.44
10.72.4.39
10.72.4.49
10.72.4.59
10.72.4.60
10.72.5.46
10.72.5.31
10
10
10
100
100
100
100
100
100
100
100
100
100
10
100
100
100
Unk
Unk
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
FD
FD
FD
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
Description
Unknown
Unknown
Util
Can_Dev
Can_Tay1
Water_1
Can_Tay4
Can_Tay5
FMC3
Hydro_Mix
FMC1
Water_2
Seamer_BC_Chk/Wgh
Seamer_BC_Chk/Wgh
Seamer_F
Seamer_B
Mixers
Net_Monitor
Engr-WS5
VMP
Condux
MP_Tay2
MP_Tay1
SFM_1
MP_Line1
OFM_1
Bag_Dump
MACS2
OFM_2
MP_Tay3
SFM1_B
Tank
Waste
MP_Line2
MP_TagsServer1
MP_TagsServer2
OFM
Tank
Type
Notes
PC Dell PC
PC Dell PC
PLC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PLC
PC Check Link
PLC
PLC
PLC
PC
PC
PLC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PLC
PC
PC
PC
PC
PLC
PLC
13
s
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
MFG
Development
Development
Development
Development
Development
Development
Development
Development
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
25
26
27
28
29
31
32
33
34
35
36
43
47
1
2
3
4
6
13
14
17
1
2
3
5
6
9
11
13
15
16
18
19
20
21
23
26
28
30
31
00-00-54-10-52-a5
00-00-54-10-89-cd
00-00-54-10-89-d1
00-00-54-10-89-d2
00-00-54-10-3f-71
00-b0-d0-55-69-dc
00-c0-4f-c9-f9-f6
00-00-54-10-89-ce
00-00-54-10-52-58
00-b0-d0-81-92-d4
00-b0-d0-61-02-17
00-08-74-41-92-8e
00-c0-4f-6b-80-71
00-06-5b-0e-af-a8
00-06-5b-1d-95-eb
00-60-b0-41-c4-1f
00-b0-d0-f5-34-e7
00-06-5b-0e-af-b2
00-c0-4f-79-a5-80
00-c0-4f-98-d3-68
aa-00-04-00-02-6c
00-b0-d0-90-4a-69
00-c0-4f-68-b6-63
00-08-74-41-82-b8
00-b0-d0-c6-d1-80
00-08-74-41-7c-f4
00-c0-4f-68-b6-72
00-b0-d0-b1-03-10
00-c0-4f-79-a5-7d
00-60-b0-f2-41-da
00-c0-4f-98-ba-ca
00-c0-4f-79-ef-f4
00-c0-4f-79-ec-f7
00-c0-4f-68-84-29
00-c0-4f-b9-b2-ad
00-00-54-10-3f-d1
00-b0-d0-60-ff-0a
00-b0-d0-b5-2d-e7
00-b0-d0-63-a9-1a
00-20-bd-06-93-0e
10.72.5.32
10.72.5.45
10.72.5.33
10.72.5.42
10.72.5.43
10.72.4.55
10.72.4.54
10.72.5.47
10.72.5.41
10.72.4.57
10.72.4.56
10.72.4.45
10.72.4.48
10.72.4.43
10.72.4.46
10.72.4.132
10.72.4.47
10.72.4.52
10.72.4.38
10.72.4.40
10.72.4.1
10.72.4.63
10.72.4.64
10.72.4.85
10.72.4.116
10.72.4.71
10.72.4.111
10.72.4.160
10.72.4.76
10.72.4.133
10.72.4.61
10.72.4.73
10.72.4.74
10.72.4.66
10.72.4.72
10.72.5.59
10.72.4.79
10.72.4.114
10.72.4.118
10.72.4.99
100
100
100
100
100
100
10
100
100
100
100
100
100
100
100
100
100
100
100
100
FD
FD
FD
FD
FD
FD
HD
FD
FD
FD
FD
FD
FD
Unk
Unk
Unk
Unk
Unk
Unk
Unk
100
100
100
100
100
100
100
100
100
100
100
100
100
10
100
100
100
100
10
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
HD
FD
FD
FD
FD
HD
Batch
Batch
OFM
SFM2
Dries
SFM2_B
MP_Tay7
SFM_2
CIP
SFM2_C
SFM2_B
SFM2_D
MACS1
MP_Tay4
MP_Dev1
Engr_DJ890
MP_Dev2
MP_Tay5
MP_Dock1
MP_Dock
Router
Seamer_F
Seamer_D
Mix_Tay
Depal_Tay
Gravy_WW2
PKG_WW
CVS_1
Mixers
Cannery_LJ4P
Can_Office
Mixer_1
Mixer_3
Seamer_C
Seamer_A
Gravy
Gravy_WW3
PKG_Tay3
PKG_WW3
Power_Mon_Meter
PLC
PLC
PLC
PLC
PLC
PC
PC Check Link
PLC
PLC
PC
PC
PC
PC
PC
PC
PRN
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PRN
PC
PC
PC
PC
PC Check Link
PLC
PC
PC
PC
PC Check Link
14
s
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Core_2
Packaging
Packaging
Packaging
Packaging
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
PKG1B
11
13
15
16
18
19
20
21
23
26
28
30
31
33
36
9
10
11
12
2
3
4
5
6
7
8
9
10
13
14
15
16
18
19
22
23
26
27
28
29
00-b0-d0-b1-03-10
00-c0-4f-79-a5-7d
00-60-b0-f2-41-da
00-c0-4f-98-ba-ca
00-c0-4f-79-ef-f4
00-c0-4f-79-ec-f7
00-c0-4f-68-84-29
00-c0-4f-b9-b2-ad
00-00-54-10-3f-d1
00-b0-d0-60-ff-0a
00-b0-d0-b5-2d-e7
00-b0-d0-63-a9-1a
00-20-bd-06-93-0e
00-b0-d0-b5-30-aa
00-00-54-10-47-d1
00-06-5b-0e-ca-f1
00-b0-d0-55-4a-20
00-b0-d0-b5-2d-e3
00-b0-d0-82-6a-59
00-00-54-10-3f-b7
00-00-54-10-3f-a3
00-00-54-10-47-da
00-00-0a-30-92-f9
00-b0-d0-61-02-0f
00-00-54-10-47-8a
00-00-54-10-3f-b6
00-00-54-10-3f-b9
00-00-54-10-3f-b0
00-06-5b-0e-cb-05
00-00-54-10-3f-a6
00-00-54-10-48-c5
00-b0-d0-61-01-6d
00-06-5b-0e-af-aa
00-00-54-10-a5-bb
00-06-5b-0e-ca-ea
00-30-11-02-00-b9
00-b0-d0-61-01-fd
00-06-5b-0e-c5-72
00-b0-d0-f2-ff-e7
00-00-54-10-3f-a4
10.72.4.160
10.72.4.76
10.72.4.133
10.72.4.61
10.72.4.73
10.72.4.74
10.72.4.66
10.72.4.72
10.72.5.59
10.72.4.79
10.72.4.114
10.72.4.118
10.72.4.99
10.72.4.119
10.72.5.101
10.72.4.115
10.72.4.117
10.72.4.121
10.72.4.113
10.72.5.89
10.72.5.82
10.72.5.90
10.72.4.149
10.72.4.141
10.72.5.84
10.72.5.81
10.72.5.83
10.72.5.94
10.72.4.175
10.72.5.95
10.72.5.87
10.72.4.148
10.72.4.156
10.72.5.92
10.72.4.153
10.72.5.152
10.72.4.155
10.72.4.162
10.72.4.157
10.72.5.97
100
100
100
100
100
100
100
10
100
100
100
100
10
100
100
100
100
100
100
100
100
100
10
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
FD
FD
FD
FD
FD
FD
FD
HD
FD
FD
FD
FD
HD
FD
FD
Unk
Unk
Unk
Unk
FD
FD
FD
HD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
FD
CVS_1
Mixers
Cannery_LJ4P
Can_Office
Mixer_1
Mixer_3
Seamer_C
Seamer_A
Gravy
Gravy_WW3
PKG_Tay3
PKG_WW3
Power_Mon_Meter
PKG_WW4
Gravy_Pouch
PKG_Tay4
PKG_WW2
PKG_Tay5
PKG_Tay2
Cassete_Shuttle_Cell-1
Chunk_Conveying
Cassete_Shuttle_Cell-2
Toyolink_Node
PO_Dev1
Cassette_Loading_Cell-2
Retort_Cooling
Cassette_Loading_Cell-1
Retort_1C
PO_Garvens
Retort_2A
Cassette_Unloading_Cell-2
PO_Training2
Cell1_Retort
Retort_1A
Cell2_Retort
Unknown
Cell1_Filler
Cell2_Unload
Chunk2
Retort_2C
PC
PC
PRN
PC
PC
PC
PC
PC
PLC
PC
PC
PC
PC
PC
PLC
PC
PC
PC
PC
PLC
PLC
PLC
Unk
PC
PLC
PLC
PLC
PLC
PC
PLC
PLC
PC
PC
PLC
PC
Unk
PC
PC
PC
PLC
Check Link
Check Link
Check Link
HMS_Fldbus
15
s
PKG2B
PKG2B
PKG2B
PKG2B
PKG2B
PKG2B
PKG2B
PKG2B
PKG2B
PKG2B
PKG2B
PKG2B
PKG2B
Spare
Spare
Spare
Spare
Spare
Spare
Spare
Spare
Spare
Spare
Spare
Spare
Spare
Unk
7
8
8
9
10
11
12
13
15
19
25
26
37
1
3
4
6
12
14
15
20
23
24
25
31
36
Unk
00-00-54-10-89-cf
00-c0-4f-96-bf-9c
00-00-bc-1e-15-aa
00-00-bc-1e-2f-63
00-06-5b-0e-b2-2a
00-06-5b-40-d1-c1
00-08-74-92-35-ce
00-08-74-92-35-cc
00-06-5b-40-d2-2f
00-b0-d0-d9-b8-28
00-06-5b-de-85-60
00-06-5b-de-85-7e
00-00-d1-89-59-41
00-b0-d0-61-02-16
00-04-75-87-dd-60
00-b0-d0-84-07-0c
00-c0-4f-98-ba-a4
00-c0-4f-79-76-1a
00-30-c1-ab-a7-a4
00-c0-4f-8f-9a-be
00-80-5f-c1-89-6e
00-80-5f-9f-6c-41
00-b0-d0-90-4a-6d
00-c0-4f-79-a5-de
00-b0-d0-61-01-6c
00-08-74-40-36-23
Unknown
10.72.5.105
10.72.4.106
10.72.5.106
10.72.5.107
10.72.4.167
10.72.4.171
10.72.4.173
10.72.4.174
10.72.4.172
10.72.4.166
10.72.4.170
10.72.4.169
10.72.4.176
10.72.4.22
10.72.4.179
10.72.4.14
10.72.4.20
10.72.4.25
10.72.4.136
10.72.4.27
10.72.4.11
10.72.4.12
10.72.4.29
10.72.4.30
10.72.4.147
10.72.4.28
10.72.4.200
100
10
10
10
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
Unk
FD
HD
HD
HD
FD
FD
FD
FD
FD
FD
FD
FD
FD
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
Unk
PCP2
Waste_Boil1
Pouch_Palletizer
Pouch_Case_Conveyor
Unknown
Cell1_TrayLoader
PO_TagSrvr1
PO_TagSrvr2
Cell2_TrayLoader
PO_Palletizer
Cell2_Packaging
Cell1_Packaging
Unknown
Engr_WS2
Unknown
Engr_WS1
Sun_Flower
Tank_Receive
HPC_Laser
Engr_WS7
NT_Srvr_P
NT_Srvr_B
Power_Monitor
Office_1
PO_Training1
Unknown
Unknown
PLC
PC
PLC
PLC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PRN
PC
PC
PC
PC
PC
PC
PC
Check Link
Check Link
Check Link
Dell PC
Adaptec NIC
3Com NIC
Dell PC
Contact
For a detailed network analysis including assistance with re-configuration, optimization and
testing contact Schneider Electric Network Certification Services toll free at 888-266-8705.
Schneider maintains an experienced staff of IT/Automation professionals with specialized tools to
certify cabling and skills in all major network OEM platforms with unique experience in Ethernet
Control Networks.
16
s
Glossary of Terms and Test Parameters
Each segment of media was tested using a swept frequency instrument. Each test is performed by
scanning and reporting tests on each pair of media, at up to six frequencies raging from 1 MHz to 100
MHz. At each frequency, an algorithm based upon TIA/EIA 568-A is applied to determine an acceptable
result for that frequency. The difference between the acceptable value at that frequency, and the actual
valued measured, is termed the Margin. For tests involving multiple pairs on the same cable, the “worst
case” margin result of the pairs tested is termed the Overall Margin.
Each network segment is tested in a non-destructive process, from the termination at the field device, to
the termination at a hub or switch. Such a test requires that the device end termination and hub/switch
end termination be disconnected briefly during the procedure. This method of testing accommodates all
terminations, patch panels, cabling sections and punch down blocks for an accurate measurement of
segment performance. Such a method can detect failing segments, or segments in which marginal effects
are cumulative and thus may not be detected by tests on individual sections. Should an overall Ethernet
segment fail, each media component in that segment is tested individually to determine the source of the
failure. Test data analysis from the failed component, and careful visual inspection, will determine the root
cause of the failure. Physical inspection involves examining each component for:






Proper matching of components
Adequate strain relief and bend radii
Sufficient airflow, temperature and humidity control where necessary
Fit, condition and cleanliness of connector contacts
Earth grounding of devices
Ethernet topology rules application
Pass/Fail test values are based upon an established standard temperature of 20 degrees Celsius/ 68
degrees Fahrenheit.
Media Classifications
Category
Twisted Pair cabling is rated by Category levels, 3, 4, 5, 5e and 6. The category a cable is
rated at is dependent upon compliance with Transmission Performance specifications
outlined in TIA/EIA 568-A and the published addenda. These performance specifications
cover the frequency at which the cable is rated to operate and other operating
requirements such as Cross Talk and Attenuation values. Category 3 cable is rated up to
16 MHz and is suitable for 10 Mbit CSMA/CD networks. Category 4 cable is rated up to
20 MHz. Category 5 cable is rated up to 100 MHz. Category 5e, (enhanced), is rated at
100 MHz but with a more stringent requirement for NEXT, PSNEXT, Attenuation, number
of twists per foot, etc. Category 6 cabling, ratified by TIA/EIA 568-B is certified to operate
at 250 MHz
UTP
Unshielded Twisted Pair cabling is eight conductors of 22 AWG copper. Each copper
conductor has a thermoplastic coating. The eight conductors are each twisted into four
pairs with a specified number of twists per foot, (as outlined in the Category). The four
pairs are then twisted around each other, again for a specified number of twists per foot.
The twists are to reduce cross talk by canceling out opposing electrical signals. UTP
cable is also available with a Plenum fire resistant coating.
17
s
FTP
Foil Twisted Pair cabling is of similar construction to UTP, but with metallic foil shielding
over each pair to reduce interference EMI and RFI from external sources. FTP can be
rated using the same TIA/EIA Category ratings as UTP. FTP cable has an embedded
ground wire, which must be grounded at both ends.
SFTP
Similar to FTP, Shielded Foil Twisted Pair cabling has a metallic braid or sheath covering
all four pair. SFTP also has a metallic ground wire.
Multi-Mode
Fiber
Offers much higher performance with data rates up to 2 Gbs, distances up to 2 km, and
immunity from EMI or Cross Talk. Multi-mode fiber, (MMF), consists of a glass core of
varying diameters, (typically 50 or 62.5 micros), and a protective cladding of typically 125
microns. Surrounding the cladding on many manufacturer types of Multi-Mode Fiber
media is a member for strength and PVC jacket. Multi-mode fiber is typically orange in
color and is terminated by SC, (Subscriber Connector), ST (Straight Tip) bayonet
connectors, or the higher density, keyed MT-RJ connector. Multi-mode fiber is a common
and cost effective medium for Industrial Ethernet deployment. MMF Connectors are
typically beige in color.
Single-Mode
Fiber
Single-Mode Fiber-Optic media has construction similar to MMF but with a smaller core
diameter, (typically 8-9 microns), of low loss glass, and with less refraction can drive
signals much greater distances, (up to 40km). The optical lasers used for SMF
installations and labor costs associated with installation and termination can command a
substantially higher price for installation. SMF jackets are commonly yellow to distinguish
it from MMF. SMF connectors are typically blue in color.
Testing Parameters
Attenuation
Is the decrease in signal strength as it travels along the wire. This loss increases as cable
length, temperature, and frequency increase. Attenuation is also greater in smaller
`diameter than larger diameter wire. Stranded wire media also has greater attenuation
than solid conductor media. Other causes of excessive attenuation are, a poor grade of
cable, or not maintaining twists on UTP at termination points.
Cable
Length
Is determined by protocol and media used as referenced by the IEEE 802.3 standard for
Ethernet LAN Communications.
Delay
Is Propagation delay. The amount of time it takes a signal to travel along copper or fiberoptic media. Delay is one of the primary reasons there are limitations on the length or
diameter of an CSMA/CD Ethernet LAN. Maximum delay for an Ethernet segment is 570
nanoseconds, or 5.7 nanoseconds per meter. This is a result of a sender listening during
transmission to transmit the minimum frame size, (64 bytes), plus preamble (64 bits), to
detect a collision.
ELFEXT
Equal Level Far End Cross Talk is a derivative of the Far End Cross Talk measurement.
While Far End Cross Talk is a measurement similar to Near End Cross Talk, ELFEXT is
the signal transmitted from the local end and measured at the far end. However, because
the signal is attenuated, similar conductors of different lengths may have very different
results. For this reason, ELFEXT subtracts the value of attenuation from the result for a
18
s
more precise reading thus accommodating differences in length. Causes of ELFEXT
failures are similar to those for NEXT failures.
Margin
The test result Margin is the difference between an acceptable result and an actual result,
for a test on an individual pair at a given frequency. As the media is scanned at a variety
of frequencies, the acceptable result changes along with the frequency. A positive margin
value indicates, in decibels, how much a segment, or pair, exceed the test standard at
that frequency. A negative value indicates, also in decibels, the amount that the segment
does not meet the standard for that frequency.
Overall
Margin
Overall Margin represents the “worst case” condition among all pairs in a section of
segment tested. Many tests require that each pair on a cable must be tested individually,
or in conjunction with another pair. The resulting deviation, or Margin, is compared with
other results from the same cable. The worst case condition among the tests conducted
on that cable is termed the Overall Margin.
Near End-
The test device consists of two units, each unit connected to one end of the cable under
test. One unit
Far End
generates the test signal, the other unit, (remote or Far End), records the result or
reflection. This ensures that the cable is tested thoroughly and that the errors or faults
can be pinpointed as to location.
NEXT
Near End Cross Talk is the ability for a signal on one wire to propagate a signal onto an
adjacent wire. The Electro-magnetic field generated by the signal current on the wire can
interfere with transmission on other wires. Therefore, the wire pairs are twisted to cancel
each other’s opposing fields. Maintaining the twists is critical to proper Ethernet operation.
Problems could result where the receiver cannot distinguish between a legitimate
received signal and a signal that is the result of cross-talk from another pair. Causes of
NEXT failures are, failure to maintain twists at connector, (max. untwisted length at
connector for Category 5 is 0.5”), non-compliant connectors, use of flat 8 conductor patch
cables, use of Type 66 voice grade punch down blocks instead of data grade type 110
blocks, carrying other applications on pairs unused by Ethernet, and reversed, crossed or
“split pairs” which are pairs not logically grouped.
Noise
Noise is unwanted electrical or electromagnetic energy present on a line that can degrade
the quality of the signal on a cable. Noise is sometimes a contributing factor in unreliable
links thus causing many retransmissions. Passing a cable through an electromagnetic
field could cause noise (Ex. Near high power lines, motors, and generators). Ethernet
operates at +2.5v / -2.5v totaling 5v peak to peak. Noise is measured as Impulse Noise,
(IEEE 802.3 Section 12.7.4.1), expressed in the number of times over a 30 minute test
period that the induced voltage level exceeds a Butterworth Low-Pass filter threshold for
an assigned frequency. The maximum voltage levels are: 170mV @ 2 MHz, 275 mV @ 4
MHz, and 560 mV @ 10 MHz. Noise is measured on an open-ended, (disconnected both
ends), line. The noise voltage on wire pairs terminated at both ends shall not exceed the
corresponding threshold voltages more than 9 times per 1800 second interval.
PSELFEXT
Similar to PSNEXT, Power Sum Equal Level Far End Cross Talk is an algebraic
summation of the ELFEXT affects on each pair by the other three pairs. Typically
PSELFEXT results are up to
3 dB lower than the worst-case ELFEXT result at each end of the link.
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s
PSNEXT
Similar to PSELFEXT, Power Sum NEXT (PSNEXT) is actually a calculation, not a
measurement. PSNEXT is derived from an algebraic summation of the individual NEXT
effects on each pair by the other three pairs. PSNEXT and ELFEXT are important
measurements for qualifying cabling intended to support 4 pair transmission schemes
such as Gigabit Ethernet. There are four PSNEXT results at each end of the link per link
tested. Typically PSELFEXT results are up to 3 dB lower than the worst-case NEXT result
at each end of the link.
Return
Loss
Measures the uniformity of the media impedance. The measurement is relative to a
current UTP standard source impedance of 100 Ohms. Return Loss measures the
difference between the transmitted signal and the reflected signal. As cabling has
mismatches in impedance, return loss is measurable. Causes for Return Loss failure may
include non-specification cable or terminators, changes in twists, handling, installation,
and varying copper diameter.
Segment
A Network Segment is equivalent to an Ethernet segment that extends from a Data
Terminal Equipment device or DTE, (such as a PLC with an Ethernet interface), to an
Data Communications Equipment or DCE device such as a switch or hub. Qualifying a
segment for Ethernet is critical in CSMA/CD or Full Duplex Ethernet.
Section
A section is described as a length of media from one termination to another, such as a
patch cable. An Ethernet segment may be comprised of several sections as the link
passes through patch panels and punch down blocks.
Wiremap
Measures continuity of each wire end to end. Pins should be terminated for all eight
conductors with same assignments. Exception is an IRL (Inter Repeater Link) “crossover
cable” where pin assignments are TD, (Transmit Data), on one end and RD, (Receive
Data), on the other end. As Ethernet, (excepting 100BaseT4), uses only 2 pair of
conductors, (pins 1,2,3 & 6), it is possible to have a wiremap fault on an otherwise
functioning connector if conductors 7 and 8 are crossed, open or shorted. Wiremap
failures may also be due to a faulty connector, improper termination or nicked conductor
sheathing.
Standards used in Testing

IEEE 802.3 (2000 Edition) and Applicable Supplements - Carrier Sense Multiple Access with Collision Detection
(CSMA/CD) Access Method and Physical Layer Specifications

TIA/EIA 568-A (October 1995) Commercial Building Telecommunications Cabling Standard

TIA/EIA 568-A-1 (September 1997) Propagation Delay and Delay Skew Specifications for 100 Ohm 4 Pair Cable

TIA/EIA 568-A-2 (August 1998) Corrections and Additions to TIA/EIA 568-A

TIA/EIA 568-A-3 (December 1998) Addendum No. 3 to TIA/EIA 568-A

TIA/EIA 568-A-4 (December 1999) Production Modular Cord NEXT Loss Test Method and Requirements for
Unshielded Twisted Pair Cabling

TIA/EIA 568-A-5 (February 2000) - Transmission Performance Specifications for 4 Pair 100 Ohm Category 5e
Cabling
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