SIP SERVER

PROBLEM TO BE SOLVED: To provide a SIP server for reducing a memory capacity including root set information held in a server for each session and suppressing the congestion of the server. SOLUTION: The SIP server 100 is provided with: a first memory 20 for making address information on a record root header among pieces of the root set information specified by a SIP signal for each session associate with a logical number and holding a root management table which sets a single logical number about the address information on a common record root header; and a second memory 30 for holding session information excluding the address information on the record root header, instance management information used for session control, and the logical number. On the basis of the logical number held in the second memory 30, the address information on the record root header held in the first memory 20 is read. COPYRIGHT: (C)2008,JPO&INPIT