Cisco Catalyst 9400 Series Hardware Installation Manual page 146

Cannot Connect to a Switch Through the Console Port
• Console port speed
• Start-up configuration
Note
The factory default for the the BAUD environment variable is an explicit setting: BAUD variable=9600. This
variable also defaults to 9600 (implicit setting) when a variable is not set explicitly.
During initial switch configuration, proceed as follows:
1. Ensure that the terminal configuration matches the switch console port speed configuration. The following
example uses a Cisco switch as the console, and the console port number is 8. Enter the appropriate console
port number when you configure the console port speed.
Switch# configure terminal
Enter configuration commands, one per line.
Switch(config)#line 8
Switch(config-line)# speed 9600
2. Access ROMMON prompt and verify the BAUD setting on the switch—Connect the console to system
and while system is booting, after you see the the prompt, press CTRL+C to stop booting and access
ROMMON prompt. In the example, the factory default setting is retained.
rommon 1> set
BAUD=9600
<output truncated>
If you want to change this setting, you can do so now
rommon 2> set BAUD <enter new speed>
If you enter a new speed, you must redo step 1 because you will lose ROMMON access immediately after
setting a new speed.
3. Boot the image.
rommon 4> boot
During bootup, the BAUD rommon setting on the active supervisor is automatically synced to the standby.
4. Save the running configuration:
Switch# copy system:running-config nvram:startup-config
When the BAUD rommon variable is set in ROMMON mode, this value is extracted for the line console
in the running configuration, when the system reloads. However, when the system parses the
startup-configuration, the startup-configuration speed supercedes the value retrieved from BAUD. This
step gets the BAUD and startup-config line console speed to match. A mismatch can cause loss of access
to the console port.
Note Any time you manually change the BAUD speed in the ROMMON (explicitly set a new speed), you may
lose console port access after a reload, or when switch boots, depending on what the BAUD speed and the
console port speed is in the startup-configuration. The console port speed must be changed to match the new
speed setting. After console access is restored, save the configuration to synchronize BAUD ROMMON
speed, startup-configuration, and line console speed. Enter the show bootvar command to verify the new
BAUD variable setting.
Cisco Catalyst 9400 Series Switches Hardware Installation Guide
140
End with CNTL/Z.
Troubleshooting