What are two requirements for a unified in-service software upgrade? (Choose two.)
What are two requirements for a unified in-service software upgrade? (Choose two.)
For a unified in-service software upgrade (ISSU), two main requirements must be met: nonstop active routing (NSR) must be enabled on the device and the device must have dual Routing Engines. NSR ensures that the routing information is preserved during the upgrade, minimizing traffic disruption. Dual Routing Engines are necessary to perform a switchover, allowing one to take over while the other is upgraded, thus ensuring continuous operation.
The unified in-service software upgrade (ISSU) feature enables you to upgrade your device between two different Junos OS releases with no disruption on the control plane and with minimal disruption of traffic. Unified ISSU is supported only on dual Routing Engine platforms. In addition, the graceful Routing Engine switchover (GRES) and nonstop active routing (NSR) features must be enabled.