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New Member

Sup 720 failover on Cat6509during IOS upgrade

Hi All,

I have a question on Sup720 failover,can someone clarify this?

Q.When I do a IOS upgrade from one cisco ios version to other,say from 12.2(18) SXF3 to 12.2(18) SXF4,when I do a reload will the Active Sup720 engine failover to the standby side?

Will I lose the connectivity?

I want to do this upgrade without the loss of connectivity(users connected to the switchport should not experience any loss of traffic),any ideas or suggestions?

My switch is running SSO as the redundancy mode.

Thanks in Advance



Re: Sup 720 failover on Cat6509during IOS upgrade

Hi Beno,

Yes The sup-engine will failover to standby sup-engine.With SSO for the layer2 protocol stacks which are syncd, you will not face the connectivity issues.


-amit singh

New Member

Re: Sup 720 failover on Cat6509during IOS upgrade

You need to do a FSU.

First upload de neu IOS to the slavedisk.

After change de startup-config, line boot system flash to the new IOS

Save the config using copy run sta

After this, reload the standby supervisor

When the standby supervisor come alive again, the new IOS will be loaded and the redundancy will come RPR.

Now you do the switchover to the standby and do the same procedure to update the IOS on the active.

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