Patent ID: 8125980

Claim:
A user terminal connection control method in a network including a packet forwarding apparatus for connecting a plurality of user terminals to an IP network by establishing a session with each user terminal in accordance with a Point to Point Protocol (PPP), and an authentication server for performing user terminal authentication in response to an authentication request issued by said packet forwarding apparatus, said authentication server having a user management table including a plurality of subtables each prepared for each user group, respectively, each of said subtables storing user identifiers belonging to the same user group, a maximum number of connections allowed to simultaneously connect to the IP network, a current number of connections, and a preferential terminal identifier indicating a user terminal to be preferentially connected to the IP network, said method comprising: transmitting from said packet forwarding apparatus to said authentication server an authentication request message including a user identifier and a password notified from one of said user terminals and a user terminal identifier of the user terminal, prior to connecting a user terminal to the IP network; performing user authentication by said authentication server based on the user identifier and the password indicated in said authentication request message, and if the user authentication succeeds, transmitting from said authentication server to said packet forwarding apparatus an access-accept message specifying an IP address assigned to the user terminal after confirming that the current number of connections is smaller than the maximum number of connections within the user group to which the user identifier belongs, by referring to said user management table; and notifying from said packet forwarding apparatus, in response to an IP address request from said user terminal, the user terminal of the IP address specified in said access-accept message, wherein said authentication server checks said user management table to determine whether said user terminal identifier indicated in said authentication request message matches the preferential terminal identifier defined in the subtable of said user group when the current number of connections has reached the maximum number of connections for said user group, said authentication server selects one of sessions having been established by the other access allowed user terminals in said user group when the user terminal identifier matches the preferential terminal identifier, requests said packet forwarding apparatus to disconnect the selected session and transmits said access-accept message to said packet forwarding apparatus, and said authentication server transmits an access-reject message to said packet forwarding apparatus when the user terminal identifier does not match the preferential terminal identifier.