Issue
ConneXium managed switches occasionally reboot automatically when one or more of the following devices are connected to the switch:
1. Ethernet hub
2. Network interface card with auto-negotiation turned OFF


Product Line
Connexium managed switches


Resolution
The cause of this problem is a duplex mismatch between the ConneXium switch and the other device. By default, ConneXium switches are set to auto-negotiate so that the link parameters

Speed ( 10 / 100 / 1000 Mbps)
Duplex (Half / Full)

are negotiated automatically. However, if one link partner is set with auto-negotiation turned OFF this automatic configuration cannot occur, and the other link partner will be forced into a pre-determined default state (likely 100Mb/Half duplex). If there is a mismatch in speed and/or duplex capability, the port on the switch may hang and the switch is designed to automatically reboot as a self-recovery mechanism.

The solution to this problem is to configure the port settings properly on all devices. It is advised to:

1. Leave all Ethernet ports set to auto-negotiate if they are capable
2. If auto-negotiation is not available or must be disabled for some reason on one of the link partners, be sure to disable auto-negotiation on the other link partner and set the speed and duplex to match

Note that even if the switch does not reboot, duplex and speed mismatches among link partners usually results in very poor network performance so this should be avoided. In addition, this general rule of either setting both link partners to auto-negotiate or setting both link partners to the same manual settings is best practice for ALL Ethernet based devices, including non-Schneider Electric switches and devices.