Brocade Communications Systems 53-1002163-02 manual Deskew calculation failed for link link-name

8 LACP troubleshooting tips

•Make sure that LACPDUs are being received and transmitted on both ends of the link and that there are no error PDUs. This can be verified by entering the show lacp counters port-channel-numcommand and looking at the receive mode (rx) and transmit mode (tx) statistics. The statistics should be incrementing and should not be at zero or a fixed value. If the PDU rx count is not incrementing, check the interface for possible CRC errors by entering the show interface link-namecommand on the neighboring switch. If the PDU tx count is not incrementing, check the operational status of the link by entering the show interface link-namecommand and verifying that the interface status is “up.”

If a Brocade-based dynamic trunk is configured on a link and the link is not able to join the LAG:

•Make sure that both ends of the link are configured as Brocade for trunk type.

•Make sure that both ends of the link are not configured for passive mode. They must be configured as either active/active, active/passive, or passive/active.

•Make sure that the port-channel interface is in the administrative “up” state by ensuring that the no shutdown command was entered on the interface on both ends of the link.

•Make sure that the links that are part of the LAG are connected to the same neighboring switch.

•Make sure that the system ID of the switches connected by the link is unique. This can be verified by entering the show lacp sys-idcommand on both switches.

•Make sure that LACPDUs are being received and transmitted on both ends of the link and there are no error PDUs. This can be verified by entering the show lacp port-channel-numcounters command and looking at the rx and tx statistics. The statistics should be incrementing and should not be at zero or a fixed value. If the PDU rx count is not incrementing, check the interface for possible CRC errors by entering the show interface link-namecommand on the neighboring switch.

•Make sure that the fiber length of the link has a deskew value of 7 microseconds. If it does not, the link will not be able to join the LAG and the following RASLOG message is generated:

Deskew calculation failed for link <link-name>.

When a link has this problem, the show port-channelcommand displays the following:

Mux machine state : Deskew not OK.

If a Brocade-based static trunk is configured on a link and the link is not able to join the LAG:

•Make sure that both ends of the link are configured as Brocade for trunk type and verify that the mode is “on.”

•Make sure that the port-channel interface is in the administrative “up” state by ensuring that the no shutdown command was entered on the interface on both ends of the link.

If a standards-based static trunk is configured on a link and the link is not able to join the LAG:

•Make sure that both ends of the link are configured as standard for trunk type and verify that the mode is “on.”

•Make sure that the port-channel interface is in the administrative “up” state by ensuring that the no shutdown command was entered on the interface on both ends of the link.

86	Converged Enhanced Ethernet Administrator’s Guide
	53-1002163-02