Resetting the Switch Module, Cabling Distance

Chapter 3 Troubleshooting

Resetting the Switch Module

Verify Switch Module Performance

Review this section when troubleshooting switch module performance problems.

Speed, Duplex, and Autonegotiation

If the port statistics show a large amount of alignment errors, frame check sequence (FCS), or late-collisions errors, this might mean a speed or duplex mismatch.

A common issue with speed and duplex is when the duplex settings are mismatched between two switch modules, between a switch module and a router, or between the switch module 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 module performance and ensure 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 speed and duplex parameters for the ports on both ends of the connection.

•If a remote device does not autonegotiate, configure the duplex settings on the two ports to match. The speed parameter can adjust itself even if the connected port does not autonegotiate.

Autonegotiation and Network Interface Cards

Problems sometimes occur between the switch module and third-party network interface cards (NICs). By default, the switch module 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 autonegotation issues occur.

To troubleshoot autonegotiation problems, try manually setting both sides of the connection. If this does not solve the problem, there could be a problem with the firmware or software on your NIC. You can resolve this by upgrading the NIC driver to the latest version available from the manufacture.

Cabling Distance

If the port statistics show excessive FCS, late-collision, or alignment errors, verify that the cable distance from the switch module to the connected device meets the recommended guidelines. See the “Cable and Adapter Specifications” section on page B-2for cabling guidelines.