Siemens Applied Automation Advance Network Gateway with Ethernet (ANG_EN) December 2000 User’s Manual 2000590-001
Copyright Notice 2000 by Siemens Applied Automation Bartlesville, Oklahoma, 74005, U.S.A. All rights reserved. This publication is for information only. The contents are subject to changes without notice and should not be construed as a commitment, representation, warranty, or guarantee of any method, product, or device by Siemens Applied Automation.
Table of Contents Chapter 1: Chapter 2: Chapter 3: Chapter 4: 2000590-001 Preface Technical Support Safety Practices and Precautions iii v vii Advance Network Gateway 1 Introduction Specifications 1 3 Installation 9 Introduction Unpacking & Inspection Pre Installation Planning Wall or Rack Mounting Installation CE Installations Wiring Connections AC Power (Mains) Connections Data Hiway Connections Ethernet Connections 9 10 11 14 14 17 18 20 23 Data Communication Setup 25 Introduction Confi
Table of Contents, Continued Chapter 5: Parts Catalog 57 Introduction Available Parts Power Supply Assembly Removal 57 58 59 Appendix Data Hiway Testing 61 Glossary Definitions of Important Terms 63 ii • Table of Contents 2000590-001
Preface Audience & Purpose This manual is intended to introduce users to the Advance Network Gateway Ethernet (ANG_EN) unit that uses the ANCB Communications Board P/N 2020951-001. The manual includes complete instructions for proper and safe installation of the ANG_EN by installation personnel. Chapter Contents The manual provides the following information: Topic 2000590-001 Page Chapter 1. Advance Network Gateway 1 Chapter 2. Installation 9 Chapter 3. Data Communication Setup 25 Chapter 4.
Technical Support Getting Help At Siemens Applied Automation we take pride in the on going support we provide our customers. When you purchase a product, you receive a detailed manual, which should answer your questions; however, our technical support service provides a special “hot” line as an added source of information.
Safety Practices and Precautions Safety First This product has been designed and tested in accordance with IEC Publication 1010-1, Safety Requirements for Electronic Measuring Apparatus, and has been supplied in a safe condition. This manual contains information and warnings, which have to be followed by the user to ensure safe operation and to retain the product in a safe condition.
Safety Practices and Precautions, Continued Correct Operating Voltage Before switching on the power, check that the operating voltage listed on the equipment agrees with the available line voltage. Danger Arising from Loss of Ground Any interruption of the grounding conductor inside or outside the equipment or loose connection of the grounding conductor can result in a dangerous unit. Intentional interruption of the grounding conductor is not permitted.
Chapter 1 Advance Network Gateway Introduction Overview The Advance Network Gateway with the Ethernet (ANG_EN) option connects Siemens Applied Automation’s equipment residing on an Advance Data Hiway to a high speed Ethernet communication system. The ANG_EN is a selfcontained unit with its own power supply and electronics. It is available for 19-inch rack or wall mounting.
Introduction, Continued Available Configurations The Advance Network Ethernet Gateway is available in the following configurations: Description 2 • Advance Network Gateway SAA Part Number CSA/NRTL, Div 2, ADH to Ethernet, Wall Mount, CE (Copper) 2015840-001 CSA/NRTL, Div 2, ADH to Ethernet, Rack Mount, CE (Copper) 2015838-001 CENELEC, ZONE 1, ADH to Ethernet, Wall Mount, CE (Copper) 2015850-001 2000590-001
Specifications Media Interface Advance Network Communication Board (ANCB): 10BASE-T RJ-45 STP connector Ethernet Specifications Data rate: 10Mbits/sec. Maximum Cable Length Per Ethernet Specifications Maximum length to adapter concentrator/hub: 100m (328 ft) Cable Type (minimum req.
Specifications, Continued Housing, Explosion Protection, Ratings and Certifications Wall Mounted Configuration NEMA 3 (IP-54) CSA Certified for Class I, Division 2, Group A,B,C,D CENELEC non-Ex (Air purge is not required for fire protection as indicated; however, the unit may be air purged, if desired, for additional protection from environmental elements.
Specifications, Continued Figure 1-2. Rack Mount Dimensions A A D C F E B Rack Mount, Front View Rack Mount, Side View L M M Rack Mount, Rear View Figure 1-2 Description U.S.
Specifications, Continued Figure 1-3. Wall Mount Dimensions G H K I A J D E Bell housing shields to provide for hazardous area connection of field wiring. Wall Mount, Front View Wall Mount, Left Side View Dimension Table 6 • Advance Network Gateway Figure 1-3 Description G H I D E J K Wall Depth Wall Width Wall Mount Holes Horizontal Spacing Wall Height of Case Only Wall Height Including Cable Housing Wall Mount Holes Vertical Spacing Left Side Wall Clearance for Door Opening U.S.
Specifications, Continued Figure 1-4.
Chapter 2 Installation Introduction Overview This chapter is intended for installation personnel. After completing the procedures, within this Chapter, the Advance Network Gateway will be ready for operation. WARNING Ensure that all AC Power (Mains) Specification requirements and advisories are met. Failure to do so, and operating the equipment in a manner not specified, may impair the safety protection provided by the equipment.
Unpacking & Inspection Instructions After opening the carton containing the unit, remove the unit from the carton and inspect it for damage that my have occurred during transportation. Points of inspection are: Reporting Damage • Inspect exterior of unit for dents, chipped paint, scratches, etc. • Open unit and visually inspect interior mounted assemblies, connectors and printed circuit boards for damage. If there is any damage, notify your local Siemens Applied Automation representative.
Pre Installation Planning Description This section provides information that can help you in preplanning your installation. Subsequent information includes examples of how an Advance Network Gateway (ANG_EN) can be used to physically extend a single loop of the Advance Data Hiway (ADH) and a Fiber optic installation. CAUTION Before installing the Advance Network Gateway (ANG_EN) within an existing LAN consult with the LAN administrator.
Pre Installation Planning, Continued Figure 2-2 illustrates how a ANG_EN can be used to physically extend a single loop of the Advance Data Hiway (ADH) by providing a conversion from the ADH media to Ethernet, and back to the ADH media. Figure 2-2. ANG_EN Installation All segments of the system labeled “Advance Data Hiway” are according to standard installation practices (9182 Belden cable or equivalent); see Chapter 1. Specifications; page 3.
Pre Installation Planning, Continued Figure 2-3 shows an ANG_EN in a 10BASE-T to fiber optic installation. Fiber optic equipment including converters, hubs and interconnecting cable are not provided by Siemens Applied Automation. Figure 2-3. ANG_EN Fiber Optics Installation As shown in Figure 2-3. multiple ANG_EN’s may be interconnected into a single large system by using appropriate Ethernet hubs.
Wall or Rack Mounting Installation Instructions The Advance Network Gateway Unit (ANG_EN) should be: • • • Installed in a location that is free from shock and vibration. Protected from direct sunlight and extremes of temperature. It is recommended that the ANG_EN be mounted within a shelter. This prevents ANG_EN from being exposed to outside environmental conditions.
CE Installations Description This section should be used for installation sites that must conform to CE (Conformite Europeene) Certification. Typically, this does not apply to installations outside the EC unless the equipment was purchased with the explicit requirements and expectations that it shall conform to EC Electromagnetic and Radio Frequency Interference (EMI/RFI) rejection specifications. CE Installation Kit Available from Siemens Applied Automation CE Installation Kit P/N 2020264-001.
CE Installations, Continued 3. A split ferrite must be clamped to Data Hiway cables and fixed immediately to the outside of the ANG_EN; use Siemens Applied Automation part number 1173000-013 ferrite contained in CE Installation Kit. This is required to meet the Conducted Immunity requirement for CE/EMC Heavy Industrial. All other CE/EMC Heavy Industrial requirements are met without the use of a ferrite clamp. 4.
Wiring Connections Description All input ac power and communications connections are made to connectors located on the chassis power supply assembly. To gain access to the assembly, open the front panel of the ANG_EN. For Zone 1 units refer to the Figure 1-4, Zone 1 Outline Drawing. Figure 2-4.
AC Power (Mains) Connections ANG_EN Power Supply The ANG_EN Power Supply can accept 90-264 VAC, 47-63 Hz inputs without the need for setting switches or jumpers. WARNING Installation personnel shall adhere to all AC Power (Mains) Specification requirements; see Chapter 1. Specifications; page 3. Failure to do so, and operating the equipment in a manner not specified, can impair the safety protection provided by the equipment. Instructions Installation Note 18 • Installation Step Action 1.
AC Power (Mains) Connections, Continued 2000590-001 Step Action 6. Locate the power-input connector on the power supply assembly. Loosen the wire retaining screws on top of connector. Strip the insulation ¼ -inch back from each of the power supply leads. Insert each lead in the correct location, and tighten down retaining screws. 7. Locate the ANG_EN chassis ground lug and connect wire from it to the building’s ground connection. 8. Inspect all connections for shorts or loose connections. 9.
Data Hiway Connections Description This section provides instructions for connecting the ANG_EN to an existing Data Hiway. Figure 2-6. Data Hiway Connector Pin 1 Data Hiway Port 1 & 2 Connections Pin 1-ADH-A+ Pin 2-ADH-APin 3- Ground Pin 4-ADH-B+ Pin 5-ADH-BPin 6- Ground Data Hiway Cable 20 • Installation The Advance Data Hiway requires a low capacitance, twin axial, 150ohm cable. The cable can be purchased from Siemens Applied Automation.
Data Hiway Connections, Continued More Information Instructions For technical information on the Data Hiway refer to Appendix A in the Optichrom Advance Library Set, Volume 2, Board Installation and Strapping Manual. Step Action 1. Place the ANG_EN AC Power Supply (Mains) circuit breaker to OFF. On the ANG_EN Power Supply Assembly place toggle ON/OFF switch to OFF. WARNING Placing the Power Supply Assembly toggle ON/OFF switch to OFF does not remove the main voltage to the J1 terminals.
Data Hiway Connections, Continued Instructions, continued Step Action 3. Connect the Channel A Data Hiway cable to port 1, ADH + and - terminals. Repeat for port 2 for Channel B Data Hiway Cable. Pin 1 Data Hiway Port 1 & 2 Connections Pin 1-ADH-A+ Pin 2-ADH-APin 3- Ground Pin 4-ADH-B+ Pin 5-ADH-BPin 6- Ground Advance Data Hiway cable shields is grounded at one end only. If ground is at ANG_EN end, use GND terminal. 22 • Installation 4.
Ethernet Connections Description The DataNET Gateway connects to the Ethernet local area network via the RJ-45 STP connector located on the topside of the ANCB. Figure 2-7. RJ-45 STP Connector Before You Begin Read the following notes. 1. The 10BASE-T data cable requires a minimum of two twisted pair (transmit pair and a receive pair). Wire used should conform to the AT&T D-inside wire (DWI&PDS), or IBM Type 3 or better twisted-pair cable specifications, or Category 3 or 5 data grade cabling or better.
Ethernet Connections, Continued Installation Do not perform the following procedure until you have defined the IP and Subnetmask addresses; see Chapter 3. Data Communications Setup. Step 1. Action Connect the incoming Ethernet line from the Hub to the RJ-45 STP connector on the ANCB board. RJ45 STP Connector 24 • Installation 2. Place the ANG_EN AC Power Supply (Mains) circuit breaker to ON. On the ANG_EN Power Supply Assembly place toggle ON/OFF switch to ON (Figure 2-4). 3.
Chapter 3 Data Communications Setup Introduction Overview This chapter provides maintenance personnel instructions for configuring the Advance Network Gateway (ANG_EN). Once configured the ANG_EN will “tunnel” Advance Data Hiway (ADH) messages across Ethernet to another ADH by way of an Advance Maxum Analyzer or another ANG_EN. Getting Started … read through this Chapter prior to performing any procedures.
Configuring Your PC Description The Advance Network Gateway (ANG_EN) has a built-in utility for configuring the ANG_EN. The Windows HyperTerminal program, which resides on most PCs, can be used to access the utility. Other serial communication packages that support the following settings can also be used. Baud rate: Data bits: Parity: Stop bits: Flow control: Instructions 57.6k baud 8 none 1 none The following procedure uses the Windows HyperTerminal program, to connect to the ANG_EN. 1.
Configuring Your PC, Continued 5. Click OK. The Connect to dialog box opens 6. From the Connect Using scroll list choose the COM port number you will be using on the PC to connect to the ANG_EN configuration port. 7. Click OK to save the selection.
Configuring Your PC, Continued 8. Scroll each field and select the following Port Settings: Bits per second: 57600 Data Bits: 8 Parity: None Stop bits: 1 Flow Control: None 9. Click OK. The Main Menu will appear. 10. Click File and choose Properties from the drop-down menu. The Advance Network Gateway Properties box will appear 11. Click Setting tab. 12. From the Emulation scroll list select VT100. Do not change the default settings for the other parameters.
Configuring Your PC, Continued 13. Click Terminal Settings button. The Terminal Settings dialog box will appear 14. Click OK to accept the default settings. The Advance Network Gateway Properties box will appear 16. Click ASCII Setup button. The ASCII Setup dialog box will appear 17. Click OK to accept the default settings and return to the Settings tab. 18. Click OK to return to main menu. 19. From the Main menu select File/Save As. The Save AS dialog box will appear 20. Enter the short cut name.
Establishing a Connection Description Once your PC is set up, as described in Configuring Your PC, you are ready to connect to an Advance Network Gateway (ANG_EN). Getting Started … read through this Chapter prior to performing any procedures. Before You Begin 1. Ensure that the ANG_EN is not connected to the network by removing the RJ-45 plug from connector (J6) located on the edge of the Communications board; reference page 23. 2.
Establishing a Connection, Continued How to Log On The following procedure assumes that the Windows Hyper Terminal program residing on your PC has been configured, the ANG_EN is operational and the PC is connected to the ANG_EN. 1. Open Windows Hyper Terminal program on your PC or double click the shortcut icon to start; See Configuring PC. 2. Press ↵ Enter twice. The following dialog box appears 3. At the > prompt type: login password and press ↵ Enter.
Establishing a Connection, Continued Remote Connection Log On If your PC is connected to the ANG_EN configuration port you can connect to any other ANG_EN on the same network if you know the IP address of the device. 1. Open Windows Hyper Terminal program on your PC or double click the shortcut icon to start; See Configuring PC. 2. Press ↵ Enter twice, the Command Request dialog box will appear. 3. At the > prompt type: login password [IP Address].
Setting Network Address & Loop and Unit Numbers Description This section provides instructions to configure an Advance Network Gateway (ANG_EN) with its own Network Address. Before You Begin 1. Open Windows Hyper Terminal program on your PC; reference Configuring Your PC, page 26. 2. Connect and Log on to ANG_EN; reference Establishing a Connection, page 26. Important Definitions 2000590-001 Familiarize yourself with the following definitions.
Setting Network Address & Loop and Unit Numbers, Continued Instructions unit: Unit refers to a numeric number assigned to a device on the Advance Data Hiway (ADH). Typically an ANG device can have a unit number from 0- to 31. However, If the ANG is connected to an Advance Network Interface Unit (NIU), the ANG unit number must not be set to 0. iproute: The iproute variable defines the network path to the default router. This value may be set to zero if not used. 1. Log on locally to the ANG_EN.
Setting Network Address & Loop and Unit Numbers, Continued 3. Press ↵ Enter. The following message appears Configuration Change verified. Type: reset - to save configuration changes 4. To save your entry, at the Local > prompt type: reset 5. To configure the ANG_EN subnetmask, at the Local > prompt type: config netmask xxx.xxx.xxx.xxx Where xxx.xxx.xxx.xxx is the subnet mask for your network. Typically, this would be 255.255.0.0 or 255.255.255.0. 6.
Setting Network Address & Loop and Unit Numbers, Continued 10. Save all changes. At the Local > prompt Type: reset This forces the ANG_EN to save the Configuration Information and reboot using the new values. The ANG_EN has now been configured. To display the current settings, type at Local > prompt: config display 11. Connect the ANG_EN to the Advance Data Hiway; reference page 20. 12. Connect the ANG_EN to the network; see page 23.
Assigning an IP Address Overview Each Advance Network Gateway (ANG_EN) unit on a network must be assigned an IP address. This 32-bit number defines each ANG_EN’s network ID and host ID. The IP address is assigned by the user before the Gateway is physically connected to a network. See Setting Network Address & Loop and Unit Numbers, for instructions on how to enter the IP address. IP Address The IP Address consists of a 32-bit number divided into four 8-bit fields.
Editing the Address Translation Table Overview The Advance Network Gateway (ANG_EN) monitors the “local” ADH bus for messages with a “remote” destination address. The ANG_EN determines if the message destination is “remote” by searching it’s Address Translation Table (ATT). If the destination address is located remotely, the ANG_EN encapsulates the ADH message within the data portion of an IP packet and sends the message out the Ethernet port.
Editing the Address Translation Table, Continued Displaying the ATT The Address Translation Table (ATT) can be displayed using the Configuration Management routines. 1. Log on locally to the ANG_EN. 2. To display the entire ATT type at the Local > prompt: display all 3. To display a single Loop only type: display adh x Where x is the ADH Loop number. Allowable values are 1 - 8. If you leave off the x value then the Loop number will default to the Loop number of the local ANG_EN.
Editing the Address Translation Table, Continued 4. To display the ATT by IP number type: display ip xxx.xxx.xxx.xxx Where xxx.xxx.xxx.xxx is the IP address. If you leave off the IP address, the IP portion will default to the value of the local ANG_EN. Note: 255.255.255.255 and 0.0.0.0 are not allowed. Editing the ATT 1. To delete a single entry from the ATT type: del adh loop unit Where loop is the ADH loop number (1 - 8) and unit is the ADH unit number (1-31). All parameters must be specified.
Editing the Address Translation Table, Continued 2. To delete all ATT entries associated with a single IP address type: del ip xxx.xxx.xxx.xxx Where xxx.xxx.xxx.xxx is the IP address in dotted decimal notation. Note: 255.255.255.255 and 0.0.0.0 are not allowed. 3.
Editing the Address Translation Table, Continued 4. To add entries to the ATT type: add adh loop unit Where loop is the ADH loop number (1 - 8) and unit is the ADH unit number (1-31). All parameters must be specified. You can only add entries that are local to the ANG_EN. If it is not directly connected to the ADH terminals you cannot edit it.
Firmware Updates Description Periodically we will provide our ANG_EN users with firmware upgrades. Perform the following instructions to download a new ANG_EN firmware upgrade to the Communications board. A firmware upgrade will take approximately 5 minutes. Instructions The following procedure assumes that the Windows Hyper Terminal program residing on your PC has been configured, the ANG_EN is operational and the PC is connected to the ANG_EN. 1. Log on to the ANG_EN. 2.
Firmware Updates, Continued 4. Click on Send Text File. The Send Text File dialog box will appear. 5. Under Files of type select All files (*.*). 6. Under File name type in the upgrade version file name (for this example Gateway.hex). This will start the down loading of the files. Once the download has begun the block numbers will be displayed as they are transmitted. The upload will take approximately 5 minutes to complete.
Command Summary Description This section summarizes the command syntax for the Advance Network Gateway (ANG_EN) software. add Adds an ADH Unit to the Address Translation Table format: add adh loop unit Where loop is a number in the range 1- 8. Where unit is a number in the range 1-31. config This command permits configuration of the ANG_EN format: config display format: config time server ip xxx.xxx.xxx.xxx Where xxx.xxx.xxx.xxx is the IP address of the time server format: config address ip xxx.xxx.
Command Summary, Continued download This command starts download of ANG_EN firmware (used for upgrades) format: download errorlog Generates and displays error log format: errorlog Help Displays Command Summary List login Permits User access to display and configuration commands format: login password logout Permits a User to end a User session format: logout Note: The user is automatically logged out after 5 minutes netstat net Displays network statistics for Ethernet port.
Chapter 4 Troubleshooting Introduction Overview This chapter provides installation personnel with troubleshooting information to solve problems associated in the setup of the Advance Network Gateway. Chapter Highlights Before beginning the installation process read through this Chapter to familiarize yourself with the information provides.
ANCB Description Description The ANCB (Advance Network Communication Board) is the communications electronics for the unit. The ANCB plugs into to PCI slot located on the power supply assembly. A bracket fastens it to the chassis. See Figure 2-4 Power Supply/ANCB Assembly. Figure 3-1. ANCB Board A D H -A J10 D a taN E T Operation LEDS Config Port RS232 57.
ANCB LEDs Description & Operation Description This section provides maintenance personnel with information on how to use the ANCB LEDs for troubleshooting the Advance Network Gateway (ANG_EN).
ANCB LEDs Description and Operation, Continued ADHA and ADHB - During normal operation the Green LED for ADHA or ADHB will blink to indicate either receive or transmit activity on the ANG_EN channel. If a message retry is sent the Yellow LED will blink. The ADHA and ADHB LEDs are status indicators. During reset all of the LED’s will blink for ½ second while the board goes through self-test.
ANCB LEDs Description and Operation, Continued Ethernet Controller - The Green TX LED blinks whenever a message is transmitted on the Ethernet channel. The Green RX LED blinks whenever a message is received on the Ethernet channel. The Red CL LED indicates there was a collision on the Ethernet. Note: collisions are a normal occurrence on an Ethernet network.
Ethernet Troubleshooting Guide Description The most common problems associated with the Ethernet and how to correct them are given in the table below. Fault 52 • Troubleshooting Probable Cause Collisions Excessive collisions are most often caused by a physical media problem such as: 1. missing or incorrect terminators (10Base2) 2. impedance discontinuities (such as defective connectors, cable stubs, crushed cables, incorrect cable types) 3. defective network interface cards (NIC) 4.
Ethernet Troubleshooting Guide, Continued Fault 2000590-001 Probable Cause Jabber Error Jabbering can be caused by faulty NIC or driver, cabling, or grounding problems Possible causes (listed by highest probability): 1. Faulty Cable/Connectors 2. Ground problem - Induced noise 3. Faulty NIC or HUB Ghosts Error Possible causes (listed by highest probability): 1. Poor grounding 2.
Guide to Network Health Recommendations for Network Health There are no magic numbers for good, or bad, network parameters (such as: utilization and collisions). The parameters that are acceptable for a healthy network are determined by many variables. 1. Utilization should average less than 40%. If you have extended peaks of greater than 70% you may want to investigate the causes and consider configuration changes to lower the average utilization.
Obtaining Diagnostics Information Description You can access the following Diagnostic information from an Advance Network Gateway (ANG_EN). • • • Ethernet Network Status ADH Channels Status Error Log Before You Begin The following procedures assumes that the Windows Hyper Terminal program residing on your PC has been configured, the ANG_EN is operational, the PC is connected to the ANG_EN and you have logged on.
Obtaining Diagnostic Information, Continued ADH Channel Information To display the current diagnostic information for the ADH channels: 1. Log on to the ANG_EN. 2. At the > prompt type: netstat adh (a or b). The display shows the number of packets received, transmitted and the number of errors detected for each of the 31 units on the assigned loop. Error Log To display an error log specific to each ANG_EN: 1. Log on to the ANG_EN 2.
Chapter 5 Parts Catalog Introduction Overview This chapter provides maintenance personnel with a list of replaceable parts and assemblies for the Advance Network Gateway (ANG_EN). Subsequent information includes how to remove and replace the replacement part or assemblies.
Available Parts Description 58 • Parts Catalog The available ANG_EN assemblies and parts and applicable part numbers are shown below.
Power Supply Assembly Removal Instructions The following procedure removes the power supply assembly from the ANG_EN enclosure. Step Action 1. Open the front panel of the ANG_EN by loosening the four captive screws located on each corner; use 4mm Allen wrench. 2. Shut off the primary AC Power Supply line to this location. Place Power Supply toggle switch to OFF. WARNING Placing the Power Supply Assembly toggle On/Off switch to OFF does not remove the main voltage to the J1 terminals.
Appendix Data Hiway Testing How to Test the Data Hiway Post Installation Test The following test procedure tests the Channel A and Channel B Data Hiway cable connections. These test procedures insures that the signal lines are correctly installed. Referenced testing points are CH A and CH B (+) and negative (-) and shield ground termination's.
How to Test the Data Hiway, Continued Measuring Shield Continuity Data Hiway shield lead continuity can be checked by performing the following procedures: Ground Data Hiway cable shields at only one end of each segment. This practice reduces ground loop noise. Step 62 • Data Hiway Testing Procedure 1. With Data Hiway communicating with connected Nodes, temporarily disconnect Channel A shield lead from ground. 2.
Glossary Definitions Overview This section defines important Terms. Advance Network Gateway Ethernet The Advance Network Gateway Ethernet (ANG_EN) is a wall- (or rack-) mounted unit that is self-contained with power supply and all electronics. It provides internal field termination points to connect standard Advance Data Hiway cable “on one side” and Ethernet 10BaseT cabling (Unshielded Twisted Pair) “on the other side”. The Gateway unit requires 120 VAC power wired directly to it.
Definitions, Continued Late Collision A Late Collision is one that occurs after the first 64 bytes in a frame or packet. Since the smallest Ethernet frame (packet) is 64 bytes in length, late collisions will not be detected on small packets. Ethernet controllers do not retransmit packets with late collisions resulting in lost packets. Late Collisions usually appear as a bad FCS frame.
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