would like to do code upgrade one at a time in VSS 4500 switches . kindly suggest us if we are able to do that and also share the step by step procedure if possible. because cisco says that we need to completely reload VSS 4500 switch during IOS upgrade. if that is the case we need downtime but we need to maintain high availability. in VPC we are able to achieve what we are looking for but in VSS we are not sure how to do that
1. When dealing with chassis-based system, more so with VSS, there is NO SUCH THING as a "no downtime" with IOS upgrades. 2. You can try ISSU, FSU/eFSU (if it works). If it doesn't work, then your supervisor cards will take turn rebooting.
If you want to upgrade the IOS of the VSS pair, then follow this proven procedure: 1. Copy the IOS to the active supervisor card; 2. Copy the IOS to the secondary card; 3. Change the boot variable statement to instruct the supervisor card to load the new IOS and, when the new IOS fails to load, point to the old IOS; 4. Ensure the config-registry value is correct: 0x2102; 5. Save the config; and 6. Reboot. WARNING: Read the Release Notes carefully. Some IOS versions require a mandatory ROMmon upgrade before an IOS upgrade can proceed.
Thanks for your response. it seems you have given procedure for normal IOS code upgrade but I would expect procedure for the below .
as we know VSS switch is nothing but combination of two switches. while doing code upgrade how to upgrade one switch at a time in VSS without affecting traffic flow through this VSS. if this is possible we don't need to have downtime while doing code upgrade I believe. I would like to have step by step procedure for this.
1. When dealing with chassis-based system, more so with VSS, there is NO SUCH THING as a "no downtime" with IOS upgrades. 2. You can try ISSU, FSU/eFSU (if it works). If it doesn't work, then your supervisor cards will take turn rebooting.
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