Gigabit (1000BASE-X) Autonegotiation

[SATORU SAEGUSA]

Hi,

I want to check the details of the Gigabit autonegotiation on Catalyst switches.

Please teach me the debug commands that can check the details of the negotiation of duplex and flow control.

Thank you for your cooperation in advance.

[Drew Browning]

This command will show you what the duplex, speed, and type is negotiating to for every interface

switch#sh int status

OR

To show you details about the interface in question use this command where the "x" is the interface number.

switch#sh int gix/x/x

[Leo Laohoo]

I want to check the details of the Gigabit autonegotiation on Catalyst switches.

You have several commands: 

1.  sh interface ; or

2.  sh interface status

However, this is totally irrelevant because fibre optics only have one speed (100 Mbps, 1 Gbps or 10 Gbps) and full duplex.

The speed is totally dependent on the type of SFP module.  Current Cisco SFP do not support multi-speed. 

[SATORU SAEGUSA]

dbrowning88-san and Leo Laohoo-san:

Thank you for your answers.
However, these commands show the results of the negotiation.
I want to check the sequence details of the Gigabit autonegotiation.