Abstract: Provided is a semiconductor integrated circuit capable of reducing power consumption while continuously detecting presence of connection of a device. The semiconductor integrated circuit includes: a first pad including a detection pad and a communication pad; a plurality of IO cells each having a high-withstand voltage device which receives a voltage of the detection pad and the communication pad, and a low-withstand voltage device which outputs a voltage obtained after the voltage is stepped down. Furthermore, the semiconductor integrated circuit includes a main circuit capable of detecting the connection of the device based on a voltage output from the IO cell connected to the detection pad, and performing data communication with the device; and a sub-circuit that is connected to the high-withstand voltage device included in the IO cell connected to the detection pad, and detects the connection of the device based on a voltage of the detection pad.

Abstract: When an IPv4/v6 dual stack terminal communicating via TCP on IPv6 fails to promptly switch over to IPv4 after the ICMPv6 fails due to a soft error, the problem should be resolved at the prior stage server rather than on the complicated terminal. The server at a stage prior to the terminal receives TCP packets from the terminal to find the TCP connection status on the terminal. When the terminal connection status is SYN-SENT or SYN-RECEIVED, and the server receives an unaddressed soft error such as ICMPv6 “Destination Unreachable: no route to destination (ICMP type=1: code 0)” for that terminal, the server rewrites the ICMPv6 contents as a hard error such as “Destination Unreachable: communication with destination administratively prohibited (ICMP type=1: code 1)” and sends it the terminal.

Abstract: A conventional DHCP authentication method could not cope with a one-phase two-messages DHCP sequence involved in a Rapid-Commit option. Further, in the conventional DHCP authentication method, it is possible to replay attack at lease renewal timing and, when information used in a retransmission method between a client and a server becomes the loss of synchronization, the conventional DHCP authentication method cannot detect the loss of synchronization and has such a problem that unnecessary traffics are continuously produced. A DHCP client device includes a means that stores a user ID, a secret key, and retransmission detection method (RDM) information. A DHCP server device includes a database that is available for the retrieval of a secret key and RMD information based on a user ID as a key or an access mechanism to an external DB with the same function as that of the database.

Abstract: An object of the present invention is to solve a problem that when multicast is utilized in a network configured with virtual routers, traffic in the relay network is increased. According to the present invention, the number of multicast packets via the relay network is reduced by performing a multicast packet transfer across the virtual routers within the same router. Specifically, it is allowed to register in a multicast routing table held by each virtual router, a line interface identifier of another virtual router as outgoing line interface information, whereby multicast packet transfer from a virtual router to another virtual router is made possible. In order to specify a virtual router to share the multicast packet, each virtual router holds information to specify a virtual router having a line interface to receive the multicast traffic indicated by the multicast group address.

Abstract: Even when session control traffic such as SIP traffic to be unitarily subjected to QoS management by a manager of a session control network such as an SIP network, and loopback traffic to be freely subjected to QoS management by users coexist, QoS processing can be appropriately performed. The edge router checks a routing table and the address information of an SIP message to derive an SIP stream direction. The edge router timely selects a table that can be set by only SIP network managers, and a table that can be set by user network managers as well, determines QoS setting information by collating other SIP/SDP message information, and sets it in a QoS function unit.

Abstract: L2TP packet forwarding apparatus to be connected to at least two LACs (L2TP Access Concentrators) via L2TP sessions to receive packets transmitted from a gateway, which accommodates user terminals, in the form of a L2TP packet encapsulated in Bridge over PPP, has a lookup table indicating the correspondence of tunnel ID/session ID pairs to an identifier (VPN-IDs) of a wide area network to which a plurality of user terminals belong. The packet forwarding apparatus specifies an VPN-ID from the lookup table based on the tunnel ID and the session ID of a received packet and forwards, if it is confirmed that another tunnel ID/session ID pair associated with the same VPN-ID exists in the lookup table, the received packet to another L2TP session identified by the another tunnel ID/session ID pair in the form of a L2TP packet.

Abstract: A dummy operation instruction circuit (100) is provided for issuing a dummy operation instruction (113) to a cryptographic control circuit (101) instead of a CPU (109) or the like after being notified of execution of a cryptographic operation instruction (111) from the CPU (109) or the like. By causing operation resources (103 to 108), such as a memory, an operator, a register and the like, after the execution of the cryptographic operation instruction (111), though they are normally inactivated for that period, so that a current is consumed, it is difficult to identify timing of the end, start and the like of a cryptographic operation process based on the magnitude of a consumed current. The dummy operation instruction (113) is issued only for a period of time for which the cryptographic operation instruction (111) is not issued from the CPU (109) or the like. Therefore, the performance of the cryptographic operation process is not deteriorated.

Abstract: The present invention relates to a domain name solution method in dynamic DNS and a device for domain name solution. A dynamic DNS server includes an address translation means which assigns a host a virtual address corresponding to an actual address of the host. The dynamic DNS registration method comprises a step in which the address translation means assigns a virtual address to the host upon a registration request issued from the host and a step of storing a tuple of the actual address, virtual address, and domain name of the host, which are associated with each other.

Abstract: Even when session control traffic such as SIP traffic to be unitarily subjected to QoS management by a manager of a session control network such as an SIP network, and loopback traffic to be freely subjected to QoS management by users coexist, QoS processing can be appropriately performed. The edge router checks a routing table and the address information of an SIP message to derive an SIP stream direction. The edge router timely selects a table that can be set by only SIP network managers, and a table that can be set by user network managers as well, determines QoS setting information by collating other SIP/SDP message information, and sets it in a QoS function unit.

Abstract: When an IPv4/v6 dual stack terminal communicating via TCP on IPv6 fails to promptly switch over to IPv4 after the ICMPv6 fails due to a soft error, the problem should be resolved at the prior stage server rather than on the complicated terminal. The server at a stage prior to the terminal receives TCP packets from the terminal to find the TCP connection status on the terminal. When the terminal connection status is SYN-SENT or SYN-RECEIVED, and the server receives an unaddressed soft error such as ICMPv6 “Destination Unreachable: no route to destination (ICMP type=1: code 0)” for that terminal, the server rewrites the ICMPv6 contents as a hard error such as “Destination Unreachable: communication with destination administratively prohibited (ICMP type=1: code 1)” and sends it the terminal.

Abstract: A packet transfer apparatus connected to an internal subnetwork formed by a set of broadcast segments each accommodating terminals and for transferring, when a MAC frame including a IP address which designates a destination terminal connected to one of the segments is received from a terminal connected to another segment in the internal subnetwork, an IP packet in the MAC frame to the segment connected to the destination terminal in accordance with a terminal management table which indicates a relation of address information of each of the terminals belonging to the internal subnetwork and the segment to which the terminal is connected.

Abstract: A method of providing web accessing service and a server apparatus for carrying out the method, wherein access from a user in a LAN to a search engine is monitored, and keyword information is stored. Then, based on the keyword information, the access to the search engine is made again by a web site storage server, and resulting contents of web sites are all stored in the web site storage server.

Abstract: Even if a mistaken reply to a host name resolution request of IPv6 is issued by a DNS contents server, a requesting terminal can still acquire an IPv4 address. When a host name resolution request of IPv6 (AAAA query) is received, a DNS proxy server generates a host name resolution request of IPv4 having an identical domain name, transmits this together with the AAAA query to the DNS contents server, and determines the DNS reply which should be returned to the terminal from the contents of the DNS reply of IPv6 (AAAA reply) and the DNS reply (A reply) of IPv4 received from the DNS contents server. Hence, even if a reply message showing a domain name error is received from the DNS contents server, if the A reply is correct, the DNS proxy server generates an AAAA reply showing that the desired address does not exist, and returns this to the terminal.

Abstract: L2TP packet forwarding apparatus to be connected to at least two LACs (L2TP Access Concentrators) via L2TP sessions to receive packets transmitted from a gateway, which accommodates user terminals, in the form of a L2TP packet encapsulated in Bridge over PPP, has a lookup table indicating the correspondence of tunnel ID/session ID pairs to an identifier (VPN-IDs) of a wide area network to which a plurality of user terminals belong. The packet forwarding apparatus specifies an VPN-ID from the lookup table based on the tunnel ID and the session ID of a received packet and forwards, if it is confirmed that another tunnel ID/session ID pair associated with the same VPN-ID exists in the lookup table, the received packet to another L2TP session identified by the another tunnel ID/session ID pair in the form of a L2TP packet.

Abstract: A state control circuit gives an inactive state control signal to a CPU and an active state control signal to a data transmission circuit. In response to this, the CPU goes into the halt state and the data transmission circuit goes into the receive state. When receive processing is completed, the state control circuit gives an active state control signal to the CPU. In response to this, the CPU restores from the halt state to the operative state. The CPU gives an instruction signal to the state control circuit. The state control circuit gives an inactive state control signal to the data transmission circuit. In response to this, the data transmission circuit goes into the halt state.

Abstract: In the IGMP/MLD Proxy, a link to an upper router must be formed in a tree structure. However, in this case, if a fault is generated in the link to the upper router, multicasts to the lower networks are all disabled. Plural links to the upper router may be set up using a routing protocol such as PIM, but light and easier operations of the IGMP/MLD Proxy are lost. In view of solving this problem, alternative links may be set in addition to the links which are usually used as the links to the upper router. Usually, the IGMP/MLD is exchanged only with the links which are usually used but with the alternative link. If link-off is detected in the link to the upper router used generally, the IGMP Membership Report/MLD Listener Report packet is transmitted to the side of the alternative link and thereafter the upper link is switched through exchanges of the IGMP/MLD only with the side of the alternative link.

Abstract: In a system in which communication is performed among a plurality of devices having a mechanism of disassembling a packet into ATM cells to send them and a plurality of devices having a mechanism of assembling the received ATM cells into the packet, a frame is prevented from being lost owing to change of virtual connections in the course of transferring the frame, improving reliability of the communication on the packet level. When the switch receives a request for change of switching, it does not processes that request at once, but confirms that the cell located at the boundary of the frame has been processed, before processing the change request, so as to protect the frame. When the switch receives a request for change of switching, it protects a frame by multicasting the cells to both destinations before change and after change, for a given period of time.

Abstract: An object of the present invention is to solve a problem that when multicast is utilized in a network configured with virtual routers, traffic in the relay network is increased. According to the present invention, the number of multicast packets via the relay network is reduced by performing a multicast packet transfer across the virtual routers within the same router. Specifically, it is allowed to register in a multicast routing table held by each virtual router, a line interface identifier of another virtual router as outgoing line interface information, whereby multicast packet transfer from a virtual router to another virtual router is made possible. In order to specify a virtual router to share the multicast packet, each virtual router holds information to specify a virtual router having a line interface to receive the multicast traffic indicated by the multicast group address.

Abstract: A router apparatus 5 is provided with an ATM switch, an IP controller for performing routing control as a controller for layer 3, plural kinds of interfaces which are individually provided to plural transmission paths in which various communications are performed, and a cell multiplexing/demultiplexing unit, and manages the cell communications between respective parts on the basis of identification information. The input packet is subjected to IP processing in an interface to be converted to a cell in a common format, and the cell is serially multiplexed with a cell from another interface on a cell basis, and transmitted to the ATM switch at the cell multiplexing/demultiplexing unit. Each interface and each cell multiplexing/demultiplexing unit sets and switches the identification information for the header portion of the packet and the cell to be communicated by using a table in which the corresponding relationship of the identification information is registered.

Abstract: A server having a function of authenticating a user, a function of confirming a connection state of the user by periodically transmitting a re-authentication request packet or a connection confirmation packet to the user and receiving a response, and a function of setting policy routing of an access server is used. A terminal communicates with the server instead of a Web browser to perform authentication at the initial start-up stage, and activates a client for responding to the re-authentication request packet or connection confirmation packet to thereby retain the connection state. Alternatively, a server having a function of authenticating a user is installed at the position of the authentication Web server. The terminal communicates with the server instead of the Web browser to perform authentication at the initial start-up stage, and a client for periodically performing authentication is activated thereafter to thereby retain the connection state.