1.
Power off the newly created switch stacks.
2.
Reconnect them to the original switch stack through their StackWise Plus ports.
3.
Power on the Device.
For the commands that you can use to monitor the switch stack and its members, see the
Displaying Switch
Stack Information
section.
Preventing Autonegotiation Mismatches
The IEEE 802.3ab autonegotiation protocol manages the device settings for speed (10 Mb/s, 100 Mb/s, and
1000 Mb/s, excluding SFP module ports) and duplex (half or full). There are situations when this protocol
can incorrectly align these settings, reducing performance. A mismatch occurs under these circumstances:
• A manually set speed or duplex parameter is different from the manually set speed or duplex parameter
on the connected port.
• A port is set to autonegotiate, and the connected port is set to full duplex with no autonegotiation.
To maximize the device performance and ensure a link, follow one of these guidelines when changing the
settings for duplex and speed:
• Let both ports autonegotiate both speed and duplex.
• Manually set the speed and duplex parameters for the ports on both ends of the connection.
If a remote device does not autonegotiate, configure the duplex settings on the two ports to match. The speed
parameter can adjust itself even if the connected port does not autonegotiate.
Note
Troubleshooting SFP Module Security and Identification
Cisco small form-factor pluggable (SFP) modules have a serial EEPROM that contains the module serial
number, the vendor name and ID, a unique security code, and cyclic redundancy check (CRC). When an SFP
module is inserted in the Device, the Device software reads the EEPROM to verify the serial number, vendor
name and vendor ID, and recompute the security code and CRC. If the serial number, the vendor name or
vendor ID, the security code, or CRC is invalid, the software generates a security error message and places
the interface in an error-disabled state.
The security error message references the GBIC_SECURITY facility. The Device supports SFP modules and
does not support GBIC modules. Although the error message text refers to GBIC interfaces and modules, the
security messages actually refer to the SFP modules and module interfaces.
Note
If you are using a non-Cisco SFP module, remove the SFP module from the Device, and replace it with a
Cisco module. After inserting a Cisco SFP module, use the
errdisable recovery cause gbic-invalid
global
configuration command to verify the port status, and enter a time interval for recovering from the error-disabled
state. After the elapsed interval, the Device brings the interface out of the error-disabled state and retries the
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Troubleshooting the Software Configuration
Preventing Autonegotiation Mismatches
