Configuring Auto Negotiation

Autonegotiation is a signalling mechanism in which two devices connected over Ethernet can choose common transmission parameters such as speed, duplex, mode and flow control.

In this process, the connected device first shares its capabilities regarding these parameters and then chooses the highest performance mode that both support.

Reference

Command	[no] autoneg disable
Description	Enable/disable auto negotiation
Parameters	None
Mode	INTERFACE

Example

pbnoscli# configure terminal 
pbnoscli(config)# interface ethernet Ethernet1/1
pbnoscli(config-if)# autoneg 
  disable               Disable Auto-Negotiation
pbnoscli(config-if)# autoneg disable
pbnoscli(config-if)#  

//to enable again
pbnoscli(config-if)# no autoneg disable 
pbnoscli(config-if)# 

You can verify the configuration by using the command(s) below:

pbnoscli# show interface status 
================================================================================================
Port            Name                            Oper    Admin   Vlan    Speed   MTU     AutoNeg 
================================================================================================
Ethernet1/1     etp1                            up      up      trunk   100000  9100    off     
Ethernet2/1     etp2                            up      up      trunk   100000  9100    N/A     
Ethernet3/1     etp3                            up      up      trunk   100000  9100    N/A     
Ethernet4/1     etp4                            down    up      trunk   100000  9100    N/A     
Ethernet5/1     etp5                            down    up      trunk   100000  9100    N/A     
Ethernet6/1     etp6                            down    up      trunk   100000  9100    N/A     
Ethernet7/1     etp7                            down    up      trunk   100000  9100    N/A     
Ethernet8/1     etp8                            down    up      trunk   100000  9100    N/A     
Ethernet9/1     etp9                            down    up      trunk   100000  9100    N/A     
Ethernet10/1    etp10                           down    up      trunk   100000  9100    N/A     
Ethernet11/1    etp11                           down    up      trunk   100000  9100    N/A     
Ethernet12/1    etp12                           down    up      trunk   100000  9100    N/A     
Ethernet13/1    etp13                           up      up      trunk   100000  9100    N/A     
Ethernet14/1    etp14                           up      up      trunk   100000  9100    N/A     
<...>
Ethernet60/1    etp60                           down    up      trunk   100000  9100    N/A     
Ethernet61/1    etp61                           down    up      trunk   100000  9100    N/A     
Ethernet62/1    etp62                           down    up      trunk   100000  9100    N/A     
Ethernet63/1    etp63                           up      up      routed  100000  9100    N/A     
Ethernet64/1    etp64                           up      up      routed  100000  9100    N/A     
pbnoscli#   

pbnoscli# show running-config 
configure terminal
!
interface ethernet Ethernet1/1
autoneg disable
!
interface ethernet Ethernet4
description interface description
!
interface mgmt
ip address 10.4.4.53/23 gateway 10.4.4.1
!
pbnoscli#