There are two methods of performing an ISSU upgrade: a four command procedure and a one command procedure. This section details how to use the one command version. The ‘quick’ option is not used as it not recommended in the installation notes due to issues with Layer 3 links flapping.
A new s/w image was downloaded to the USB interface. It was then copied to each bootflash and the ISSU command issu changeversion was entered. Note: In order to run this procedure the configuration register on each supervisor had to be changed from the factory default of 0x2101 to 0x2102. This required that each supervisor be reset prior it the ISSU command being executed.
The procedure is as follows:-
Note that the procedure reloads the standby first and then the active so at the end of the procedure the new Active is the original Standby supervisor. To swap Active and Standby use the following command (assumes this done during a change window).
Please refer to the following document for details of configuring ISSU