Abstract: When a connection control device determines that the connection control device is in a congested state, based on whether a usage of at least one of hardware resources necessary for call processing to establish a call connection is equal to or more than a predetermined threshold value, the CPU of the connection control device forcefully disconnects an established call connection after a connection available time elapses, and, when an INVITE message is transmitted from a terminal device, the CPU of the connection control device receives the INVITE message, calculates the wait time, creates and transmits a response message stating the wait time, and stores the message as a reserved call on a reservation list.

Abstract: A network quality monitoring device includes a packet receiving unit that receives packets used by a signaling protocol server device that is a server device for processing the signaling protocol, a signaling protocol packet extracting unit that extracts signaling protocol packets for controlling the signaling protocol from packets received by the packet receiving unit, a session management table storing unit that stores the session management tables, a signaling protocol quality analyzing unit that collects quality information regarding the network quality from a session management table corresponding to sessions that have transitioned to a predetermined communication state among the session management tables stored in the session management table storing unit and, based on the collection result, analyzes statistical information regarding the network quality.

Abstract: A SIP server 100 includes a first memory 20 storing a route management table in which, of route set information specified by a SIP signal on a session-by-session basis, address information as of each Record-Route header value is associated with a logical number, the same address information as of a Record-Route header values being set to the same single logical number; and a second memory 30 storing session information other than the address information as of each Record-Route header value, instance management information for use in session control, and logical numbers. The address information as of each Record-Route header value, which is stored in the first memory 20 is read on the basis of the logical numbers stored in the second memory 30.

Abstract: A network quality monitoring device includes a packet receiving unit that receives packets used by a signaling protocol server device that is a server device for processing the signaling protocol, a signaling protocol packet extracting unit that extracts signaling protocol packets for controlling the signaling protocol from packets received by the packet receiving unit, a session management table storing unit that stores the session management tables, a signaling protocol quality analyzing unit that collects quality information regarding the network quality from a session management table corresponding to sessions that have transitioned to a predetermined communication state among the session management tables stored in the session management table storing unit and, based on the collection result, analyzes statistical information regarding the network quality.

Abstract: The SIP server includes a SIP communication controller for controlling transmission/reception of a SIP message complying with SIP, a SIP call controller for controlling calls by using SIP, a call data manager for managing communication state information which indicates communication state with the opposing server and bypass requirement information which indicates the need of skipping the opposing server determined for each session communication on the basis of recovery state of the opposing server, a bypass controller for determining whether to skip the opposing server which is set to be the next destination for each session communication in relaying the SIP message on the basis of the communication state information and the bypass requirement information of the opposing server, and a SIP header controller for editing a Route header of the SIP message in accordance with the result of the determination by the bypass controller.

Abstract: A SIP server 100 includes a first memory 20 storing a route management table in which, of route set information specified by a SIP signal on a session-by-session basis, address information as of each Record-Route header value is associated with a logical number, the same address information as of a Record-Route header values being set to the same single logical number; and a second memory 30 storing session information other than the address information as of each Record-Route header value, instance management information for use in session control, and logical numbers. The address information as of each Record-Route header value, which is stored in the first memory 20 is read on the basis of the logical numbers stored in the second memory 30.

Abstract: A communication state between a session initiation protocol server and another session initiation protocol server to be a destination for transmitting a request message is determined. When it is determined that the communication state is in a communication unavailable state, a subsequent session initiation protocol server of the session initiation protocol server designated as the destination is determined to be a new destination based on information on a relay order of the session initiation protocol servers set in header information of the request message.

Abstract: When a connection control device determines that the connection control device is in a congested state, based on whether a usage of at least one of hardware resources necessary for call processing to establish a call connection is equal to or more than a predetermined threshold value, the CPU of the connection control device forcefully disconnects an established call connection after a connection available time elapses, and, when an INVITE message is transmitted from a terminal device, the CPU of the connection control device receives the INVITE message, calculates the wait time, creates and transmits a response message stating the wait time, and stores the message as a reserved call on a reservation list.

Abstract: A printed-circuit board according to the present invention includes: a plurality of insulating layers; a plurality of conductive patterns formed in each insulating layer; and a plurality of closed and curved patterns each formed around the conductive patterns in each insulating layer, and each formed by a material having a coefficient of linear thermal expansion smaller than that of the insulating layer. In this case, each closed and curved pattern is made of copper and formed of same material as that of each conductive pattern. Further, when the coefficient of linear thermal expansion of each insulating layer is &agr;1, when the coefficient of linear thermal expansion of each conductive layer is &agr;2, and when the coefficient of linear thermal expansion of each closed and curved pattern is &agr;3, the following condition, i.e., &agr;1>&agr;2≧&agr;3, is satisfied.