Allen-Bradley armorstratix 5700, User Manual, Page: 334 / 458

334 Rockwell Automation Publication 1783-UM007I-EN-P - December 2017
Chapter 5 Troubleshoot the Switch
Troubleshoot Switch
Performance The following table includes basic troubleshooting for issues that are related to
switch performance.
Issue Resolution
Speed, duplex, and autonegotiation Port statistics that show a large amount of alignment errors, frame check sequence (FCS), or late-collisions errors can
indicate a speed or duplex mismatch.
Common speed and duplex issues occur when duplex settings are mismatched between two switches, between a switch
and a router, or between the switch and a computer. These issues can occur from manually setting the speed and duplex
or from autonegotiation issues between the two devices. A mismatch occurs under these circumstances:
• A manually set speed or duplex parameter differs from the manually set speed or duplex parameter on the
connected port.
• A port is set to autonegotiate, and the connected port is set to full-duplex with no autonegotiation.
To maximize switch performance and be sure of a link, follow one of these guidelines when changing the settings for
duplex and speed:
• Let both ports autonegotiate both speed and duplex.
• Manually set the same speed and duplex parameters for the ports on both ends of the connection to the same
values.
• If a remote device does not autonegotiate, configure the duplex settings on the two ports to the same values.
The speed parameter can adjust itself even if the connected port does not autonegotiate.
Autonegotiation and network interface cards (NICs) Issues sometimes occur between the switch and third-party network interface cards (NICs). By default, the switch ports
and interfaces are set to autonegotiate. It is common for devices like laptops or other devices to be set to autonegotiate
as well, yet sometimes autonegotiation issues occur.
To troubleshoot autonegotiation issues, try manually setting both sides of the connection. If the issues persist, try
upgrading the NIC driver to the latest firmware or software.
Cable distance If the port statistics show excessive FCS, late-collision, or alignment errors, verify that the cable distance from the switch
to the connected device meets the recommended guidelines.