Rockwell Automation 1783-BMxxx Stratix 5700 Ethernet Managed Switches User Manual - Manual (Page 237)

Rockwell Automation Publication 1783-UM004E-EN-P - June 2014 237
Troubleshoot the Switch Chapter 6
Switch Performance These are some basic troubleshooting for issues related to switch performance.
Access Direct Managed Mode You can display the Device Manager Web interface and manage the switch
through a physical connection between one of the switch ports and your
computer or laptop. This type of management connection is referred to as the
Direct Managed mode. This mode is typically used to connect to the switch by
using the Device Manager Web interface when the IP address of the switch is
unknown.
Before you can access Direct Managed mode, you must make sure of the
following:
• You must have physical access to the switch.
• Make sure that at least one switch port is enabled and is not connected to a
device.
Issue Resolution
Speed, Duplex, and Autonegotiation If the port statistics show a large amount of alignment errors, frame check sequence (FCS), or late-collisions errors, this
can indicate a speed or duplex mismatch.
A common issue with speed and duplex occurs when the duplex settings are mismatched between two switches,
between a switch and a router, or between the switch and a workstation or server. This can happen when 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 is different 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 this does not solve the issue,
there could be an issue with the firmware or software on your NIC. You can resolve this by upgrading the NIC driver to the
latest firmware or software available from the manufacturer.
Cabling 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.