Patent ID: 8095681
Filing Date: 2012-01-10
Classification: H04L

Abstract:
1. A load balancing system connected to a plurality of terminals within a local domain and terminals and session control servers in one of other domains, said load balancing system comprising: a plurality of session control servers; and a load balancing server, the load balancing server comprising: wherein, upon determining that the source is a terminal or session control server in said one of other domains, the control unit transmits the packet via the transmitting/receiving unit to one session control server of the plurality of session control servers for performing session control that belongs to a same domain as a destination terminal of said packet, wherein if the control unit determines the source to be a terminal within said local domain, said control unit determines a session control server that performs session control for the terminal within the local domain out of said plurality of session control servers, and notifies the terminal of the address of the determined session control server via said transmitting/receiving unit, wherein if the control unit determines the source to be a terminal within said local domain, said control unit further registers a relation in a location database of the load balancing system between the terminal within the local domain and the session control server that performs session control for the terminal, wherein, upon the session control server that performs session control for the terminal receiving a logout notification from the terminal, the session control server instructs said location database to delete the registered relation, wherein each session control server of said plurality of session control servers, upon receiving a packet, refers to the location database to determine whether a source of the packet is a terminal for which the session control server that received the packet is responsible for performing session control, and, upon a determination that the source is not a terminal for which the session control server that received the packet is responsible for performing session control, determines to not forward the packet, wherein each of said plurality of session control servers further comprises a local location database storing the addresses of each terminal for which the session control server of the plurality of session control servers is responsible for session control, and wherein, for each of said plurality of session control servers: the session control server, upon receiving a packet, determines whether a destination of the packet is a terminal within the local domain, if the session control server determines the destination is a terminal within the local domain, then the session control server searches said local location database and determines whether the destination of the packet is a terminal for which the session control server itself is responsible for session control, if the session control server determines the destination is a terminal for which the session control server itself is responsible for session control, the session control server transmits said packet to the destination, and if the session control server determines the destination is not a terminal for which the session control server itself is responsible for session control, the session control server refers to said location database, searches for an address of a session control server that performs session control for the destination terminal, and forwards said packet to the session control server thus found.