I would like to upgrade my EX4550 with a minimal service disruption.
I read there is a ISSU or NSSU procedure which sould accomplish this task.
First of all I would like to understand if there is a difference between ISSU and NSSU (aprt from the acronym).
Then I would ask you if there is a minimal Junos version from which the ISSU or NSSU is possbile. At the noment my EX4550 run with the 12.3R10.2 image.
ISSU system requirements
NSSU and Junos OS Release Support
Understanding Nonstop Software Upgrade on EX Series Switches