A Remote Authentication Dial In User Service, RADIUS, capability negotiation method, comprising: transmitting, by a client, to a server a first message carrying RADIUS capability parameters of the client; acquiring, by the server, the RADIUS capability parameters in the first message, matching the RADIUS capability parameters in the first message with RADIUS capability parameters of the server to obtain a matching result, and transmitting the matching result to the client through a second message; and determining, by the client, whether to establish effective communication with the server according to the matching result in the second message, characterized in that the method further comprises: after the client transmits the first message to the server, transmitting, by the server, to the client a first announcement message carrying configuration information and/or load information and/or compulsory switching information of the server; and performing, by the client, corresponding operations based on the first announcement message; wherein the performing, by the client, corresponding operations based on the first announcement message comprises: configuring, by the client, its communication parameters according to the configuration information in the first announcement message, and performing effective communication with the server; and/or configuring, by the client, assignment of a broadband user accessing the client to a server for authentication, authorization and accounting according to the load information in the first announcement message; and/or transferring compulsorily, by the client, a broadband user accessing a server to any other server according to the compulsory switching information in the first announcement message. transmitting, by a client, to a server a first message carrying RADIUS capability parameters of the client; acquiring, by the server, the RADIUS capability parameters in the first message, matching the RADIUS capability parameters in the first message with RADIUS capability parameters of the server to obtain a matching result, and transmitting the matching result to the client through a second message; and determining, by the client, whether to establish effective communication with the server according to the matching result in the second message, characterized in that the method further comprises: after the client transmits the first message to the server, transmitting, by the server, to the client a first announcement message carrying configuration information and/or load information and/or compulsory switching information of the server; and performing, by the client, corresponding operations based on the first announcement message; after the client transmits the first message to the server, transmitting, by the server, to the client a first announcement message carrying configuration information and/or load information and/or compulsory switching information of the server; and performing, by the client, corresponding operations based on the first announcement message; wherein the performing, by the client, corresponding operations based on the first announcement message comprises: configuring, by the client, its communication parameters according to the configuration information in the first announcement message, and performing effective communication with the server; and/or configuring, by the client, assignment of a broadband user accessing the client to a server for authentication, authorization and accounting according to the load information in the first announcement message; and/or transferring compulsorily, by the client, a broadband user accessing a server to any other server according to the compulsory switching information in the first announcement message. configuring, by the client, its communication parameters according to the configuration information in the first announcement message, and performing effective communication with the server; and/or configuring, by the client, assignment of a broadband user accessing the client to a server for authentication, authorization and accounting according to the load information in the first announcement message; and/or transferring compulsorily, by the client, a broadband user accessing a server to any other server according to the compulsory switching information in the first announcement message.