When using separate PSNs for different sites, the network device must be added to all PSN nodes in the deployment, so that the device can communicate with the appropriate PSN based on the location of the user1. If the device is not added to all PSN nodes, the user may encounter an EAP-TLS authentication failure when moving between sites, as the device may not be able to reach the PSN that issued the certificate2. The other options are not relevant for this scenario, as they do not address the issue of PSN communication.