An OVF, or Open Virtualization Format, is a package format that allows for the distribution of virtual appliances or virtual machines. It is platform-independent and can include one or more virtual disks and a VM configuration file (typically an .ovf or .ova file). The OVF package can be used to easily deploy complex multi-tier applications across different virtualization platforms.
References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials

Priority values are 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864, 40960,
45056, 49152, 53248, 57344, and 61440. All other values are rejected.

Before you can configure Locator/ID Separation Protocol (LISP), you will need to determine the type of LISP deployment you intend to deploy. The LISP deployment defines the necessary functionality of LISP devices, which, in turn, determines the hardware, software, and additional support from LISP mapping services and proxy services that are required to complete the deployment.
LISP configuration requires the datak9 license.
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_lisp/configuration/xe-3s/irl-xe-3s- book/irl-overview.html

Stateful Switchover (SSO) provides protection for network edge devices with dual Route Processors (RPs) that represent a single point of failure in the network design, and where an outage might result in loss of service for customers.