In some examples, an authentication node of a telecommunications network can receive an authentication request from a terminal, and an authentication-control message. The authentication node can skip an authentication operation with respect to the authentication request in response to the authentication-control message. In some examples, a relay node of the telecommunications network can detect an overload or service-interruption condition and determine, in response, the authentication-control message. The relay node can send the authentication-control message to the authentication node. In some examples, an authentication node can detect that its load level satisfies a predetermined criterion and, in response, skip an authentication operation and send a first message. Another authentication node can receive an indication of the first message and, in response, perform a second authentication operation.