Assessment: To reflect the changing roles of U.S. troops on the Korean peninsula, Reception, Staging, Onward Movement and Integration (RSOI), the historical name of the annual exercise with ROK troops, was changed to Key Resolve. Key Resolve is primarily a command-post exercise with computer-based simulations that focus on deploying troops and equipment to Korea in the event of an attack, while Foal Eagle includes a series of field exercises that involves training of both nations troops. As with previous events, the United Nations Command informed Pyongyang of the routine annual defensive exercises, only to have Pyongyang immediately issue its customary war rhetoric. A stronger response than seen in recent exercises, Pyongyang also severed communications with Seoul, warned that commercial airspace over North Korea was not safe, and closed its border, temporarily stranding South Korean workers at the Kaesong Industrial Complex. On a historic note, two participating U.S. Aegis destroyers were commanded by Korean-American officers.