An entity, located in an MTA, that is responsible for controlling the MTL.It controls the operation of the protocol to other peer entities in the MTL.; 處于報(bào)文傳送代理中的一個(gè)實(shí)體,負(fù)責(zé)控制報(bào)文傳送層。 該實(shí)體對(duì)報(bào)文傳送層中其它對(duì)等實(shí)體的協(xié)議操作進(jìn)行控制。