Two statements that are true about the process of performing an EPLD upgrade on a Cisco MDS 9000 series Switch are:
* If an upgrade is interrupted, the upgrade continues after a connection is restored. This means that the EPLD upgrade process is resilient to network or power failures and can resume from where it left off once the connection is reestablished.
* The upgrade can be performed from the standby supervisor module. This allows the active supervisor module to continue to provide management and control functions while the EPLD upgrade is in progress. The standby supervisor module can also take over the active role if needed during the upgrade.
The other statements are not true because:
* The active supervisor cannot be upgraded. The EPLD upgrade process requires the supervisor module to be in standby mode before it can be upgraded. The active supervisor module must be switched to standby mode manually or automatically before the upgrade can begin.
* Modules do not need to be online to be upgraded. The EPLD upgrade process can upgrade modules that are offline or powered down as well as modules that are online. The offline modules are upgraded when they are brought online or powered up.
* The upgrade process disrupts all modules that are being upgraded. The EPLD upgrade process requires a module reload for each module that is being upgraded, which causes a temporary disruption of traffic and services on that module. The disruption can be minimized by using hitless or non-disruptive EPLD upgrade modes, which preserve the forwarding state and configuration of the module during the reload.
References: For more details on how to perform an EPLD upgrade on a Cisco MDS 9000 series Switch, please refer to the following resources:
* Cisco MDS 9000 Family NX-OS System Management Configuration Guide
* Cisco MDS 9000 Family EPLD Upgrade Release Notes