How Can I Enable or Disable Auto-Negotiation with FTOS?


This document provides a general description of port speed auto-negotiation and takes you step by step through configuring and verifying port speed with and without auto-negotiation using FTOS.

By default, auto-negotiation is enabled in FTOS on all Force10 10/100/1000 interfaces. The local interface and the directly connected remote interface must have the same setting, and auto-negotiation is the easiest way to accomplish that, as long as the remote interface is capable of auto-negotiation.

Note: As a best practice, Force10 Networks recommends keeping auto-negotiation enabled on all interfaces. Auto-negotiation should only be disabled on switch ports that attach to devices not capable of supporting negotiation or where connectivity issues arise from interoperability issues.

Step 1: Determine the current interface status.

Check the speed/duplex/auto-negotiation settings on both the local and remote ports to ensure compatible configuration.

On the Force10 switch, use the following command to determine how interfaces are currently configured:
show interfaces [interface | linecard slot-number] status

Force10#show interfaces status
Port    Description Status Speed      Duplex Vlan
Gi 0/0              Up     1000 Mbit  Auto    --
Gi 0/1              Down   Auto       Auto    1
Gi 0/2              Down   Auto       Auto    1
Gi 0/3              Down   Auto       Auto    --
Gi 0/4 Force10Port  Up     1000 Mbit  Auto   30-130
Gi 0/5              Down   Auto       Auto    --
Gi 0/6              Down   Auto       Auto    --
Gi 0/7              Up     1000 Mbit  Auto   1502,1504,1506-1508,1602
Gi 0/8              Down   Auto       Auto    --
Gi 0/9              Down   Auto       Auto    --
Gi 0/10             Down   Auto       Auto    --
Gi 0/11             Down   Auto       Auto    --
Gi 0/12             Down   Auto       Auto    --
Gi 0/13             Down   Auto       Auto    --
Gi 0/14             Down   Auto       Auto    --
Gi 0/15             Down   Auto       Auto    --
[output omitted]

! show run int
interface GigabitEthernet 0/0
no ip address
no shutdown
interface GigabitEthernet 0/1
no ip address
interface GigabitEthernet 0/2
no ip address
interface GigabitEthernet 0/3
no ip address
[output omitted]

Step 2: Set the port speed and disable auto-negotiation.

If you discover that the remote interface does not support auto-negotiation, use the command
speed {10 | 100 | 1000 | auto}, in INTERFACE mode, to set the preferred speed to 10 or 100. Then use the no negotiation auto command to disable auto-negotiation on the port. (Setting the speed to 1000 does not require disabling auto-negotiation.) Optionally, use the duplex {half | full} command to set full- or half-duplex:

Force10(config)#interface gig 0/1
Force10(Interface 0/1)#speed 100
Force10(Interface 0/1)#duplex full
Force10(Interface 0/1)#no negotiation auto

Step 4: Verify your configuration change.

You can use the show interfaces status command, as shown above, to see the updated setting.

You can also use the show config command, from within the INTERFACE mode, to verify that you set the speed and duplex mode as you intended:

Force10(Interface 0/1)#show config
interface GigabitEthernet 0/1
no ip address
speed 100
duplex full

no shutdown

Information to Collect if You Open a TAC Case

If you would like assistance from Force10 Networks after following the steps above, please use the Create Service Request form on the iSupport page and include the following information if available:

  • Console captures showing the steps taken
  • Output from the show tech-support command to capture the installed hardware and the SFTOS version
  • Network diagrams or other descriptions of the network design, including VLAN configurations and IP address ranges
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