Cisco Systems XR manual Outgoing Radius packets, SR-49

Authentication, Authorization, and Accounting Commands on Cisco IOS XR Software

radius source-interface

Examples	The following example shows how to make RADIUS use the IP address of subinterface s2 for all
	outgoing RADIUS packets:
	RP/0/RP0/CPU0:router# configure
	RP/0/RP0/CPU0:router(config)# radius source-interface Loopback 10

Cisco IOS XR System Security Command Reference

SR-49