If the low end of a connection determines that the primary trunk of a multi-trunk connection is no longer valid, a reset connection protocol is initiated. The trunk over which the reset control record is transmitted is usually the new primary trunk. The CES value will be set to indicate primary or secondary. Other conditions may cause a reset to be initiated from either end; however, the high end must never require the low end to answer the reset. Figure 1 illustrates primary assignment reset protocol.