Basically, Cisco Aggregation Services Routers (ASR) can be used as edge devices in enterprise environments. This routers supports data, voice and video conferencing traffics.
Cisco Permanent License Reservation is an offline solution benefits the customers in order to register their IOS XR devices, resides in a highly secure networks, permanently and without any direct or indirect connection to the Cisco licensing portal (CSSM).
Within Cisco Aggregation Services Router Series, Cisco ASR 900 PLR can be applied on these series activating all the features on the device permanently. For knowing about ASR 900 PLR activation process please check the link below: