Dell Command Line Reference Guide for the S4048–ON System


negotiation auto

Enable auto-negotiation on an interface.

negotiation auto

To disable auto-negotiation, use the no negotiation auto command.

Command Modes
Command History

This guide is platform-specific. For command information about other platforms, see the relevant Dell EMC Networking OS Command Line Reference Guide.

Introduced on the S6010-ON and S4048T-ON.
Introduced on the S3148.
Introduced on the S6100–ON.
Introduced on the S3100 series.
Introduced on the Z9100–ON.
Introduced on the S4048-ON.
Introduced on the S3048-ON.
Introduced on the S6000-ON.
Introduced on the S6000.
Introduced on the S4820T.
Introduced on the Z9000.
Introduced on the S4810.
Introduced on the E-Series.
Introduced on the S-Series.
Introduced on the C-Series.
Introduced on the E-Series.
Usage Information

The no negotiation auto command is only available if you first manually set the speed of a port to 10Mbits or 100Mbits.

The negotiation auto command provides a mode option for configuring an individual port to forced-master/forced slave after you enable auto-negotiation.

NOTE: The mode option is not available on non-10/100/1000 Base-T systems.
If you do not use the mode option, the default setting is slave. If you do not configure forced-master or forced-slave on a port, the port negotiates to either a master or a slave state. Port status is one of the following:
  • Forced-master
  • Force-slave
  • Master
  • Slave
  • Auto-neg Error — typically indicates that both ends of the node are configured with forced-master or forced-slave.
CAUTION: Ensure that one end of your node is configured as forced-master and one is configured as forced-slave. If both are configured the same (that is, forced-master or forced-slave), the show interfaces command flaps between an auto-neg-error and forced-master/slave states.

You can display master/slave settings with the show interfaces command.

You can use the negotiation auto command to turn autonegotiation on or off only on fiber interfaces operating at 1G speed.

If you use a 1 G SFP, disable autonegotiation on both peer ends. If you do not disable autonegotiation, the link does not come up.

Example (Master/Slave)
DellEMC(conf)# interface tengigabitethernet 1/1
DellEMC(conf-if)# neg auto
DellEMC(conf-if-autoneg)# ?

end          Exit from configuration mode
exit         Exit from autoneg configuration mode
mode         Specify autoneg mode
no           Negate a command or set its defaults
show         Show autoneg configuration information
DellEMC(conf-if-autoneg)# mode ?
forced-master Force port to master mode
forced-slave  Force port to slave mode
Example (Configured)
DellEMC# show interfaces configured
TenGigabitEthernet 1/18 is up, line protocol is up
Hardware is DellEMCEth, address is 00:01:e8:05:f7:fc
   Current address is 00:01:e8:05:f7:fc
Interface index is 474791997
Internet address is
MTU 1554 bytes, IP MTU 1500 bytes
LineSpeed 1000 Mbit, Mode full duplex, Master
ARP type: ARPA, ARP Timeout 04:00:00
Last clearing of "show interfaces" counters 00:12:42
Queueing strategy: fifo
Input Statistics:
User Information

Both sides of the link must have auto-negotiation enabled or disabled for the link to come up.

The following details the possible speed and auto-negotiation combinations for a line between two 10/100/1000 Base-T Ethernet interfaces.

Port 0
  • auto-negotiation enabled* speed 1000 or auto
  • auto-negotiation enabled speed 100
  • auto-negotiation disabled speed 100
  • auto-negotiation disabled speed 100
  • auto-negotiation enabled* speed 1000 or auto
Port 1
  • auto-negotiation enabled* speed 1000 or auto
  • auto-negotiation enabled speed 100
  • auto-negotiation disabled speed 100
  • auto-negotiation enabled speed 100
  • auto-negotiation disabled speed 100
Link Status Between Port 1 and Port 2
  • Up at 1000 Mb/s
  • Up at 100 Mb/s
  • Up at 100 Mb/s
  • Down
  • Down

* You cannot disable auto-negotiation when the speed is set to 1000 or auto.

Rate this content

Easy to understand
Was this article helpful?
0/3000 characters
  Please provide ratings (1-5 stars).
  Please provide ratings (1-5 stars).
  Please provide ratings (1-5 stars).
  Please select whether the article was helpful or not.
  Comments cannot contain these special characters: <>()\