Description

After connecting/disconnecting PD (Powered device) to the switch-port which enables auto-negotiation by default, this switch-port continues to have the previous 100mbps settings and does not auto-negotiate with the end device until the speed is manually set to 1000mbps.

Symptoms

Auto-negotiation is on by default. It works if a PoE device is not plugged in first, without needing to manually set the switchport speed. Auto-negotiation works fine if a 1000m laptop connection is directly connected to the switch port.

A conference phone with a 100mbps LAN connection is plugged into a switchport. It is then taken out and a laptop with 1Gbps (1000mbps) speed is plugged into the same switchport. This port will stay at 100mbps despite auto speed and full-duplex settings configured on all interfaces by default.

Taking the following steps do not resolve the issue.

  • Disable and re-enable the switchport.
  • Reboot the EX3400 switch.

Solution

The workaround is to manually set the switchport speed to 1000mbps using the command below.  The laptop then gets 1000mbps speed.

root@switch# # set interfaces ge-0/0/0 speed 1g