Cisco's In Service Software Upgrade (ISSU) service is actually a process or procedure to upgrade software for Cisco's hardware without actually bringing down your network or you can say with minimal disruption. alrite, Lets see how this magic works -
Cisco IOS In Service Software Upgrade significantly reduces the impact planned software upgrades and maintenance can have on service availability. ISSU changes the operational procedure for performing Cisco IOS software upgrades. The risk assessment criteria are also changed, since impact to users is much less than before.
Steps to do an ISSU are very simple -
Cisco IOS In Service Software Upgrade significantly reduces the impact planned software upgrades and maintenance can have on service availability. ISSU changes the operational procedure for performing Cisco IOS software upgrades. The risk assessment criteria are also changed, since impact to users is much less than before.
Steps to do an ISSU are very simple -
- Load new version on the standby RP
- Switchover
- Reload the new standby with the new version
And during all this process data plane continues to forward the data packets and to achieve this ISSU uses two technologies -
- Stateful Switchover (SSO)
- Non-Stop Forwarding (NSF)
lets get the best man for the presentation job into the arena, Jimmy would demonstrate the commands used along with the working of ISSU -