摘要:
When a packet transfer equipment receives a packet, it extracts several types of information contained in the received packet such as the destination IP address and the destination port number and, using the extracted information as the key, inquires of a packet transfer method resolution server about the information related to the packet transfer method. The server keeps the correspondences between several types of information contained in the packet and one or more type of information related to the packet transfer method in the database and, in response to the inquiry from the packet transfer equipment, replies one or more type of information related to the packet transfer method. The packet transfer equipment rewrites several types of information such as the destination IP address and the destination port number according to one or more type of information obtained and transfers the received packet.
摘要:
When a packet transfer equipment receives a packet, it extracts several types of information contained in the received packet such as the destination IP address and the destination port number and, using the extracted information as the key, inquires of a packet transfer method resolution server about the information related to the packet transfer method. The server keeps the correspondences between several types of information contained in the packet and one or more type of information related to the packet transfer method in the database and, in response to the inquiry from the packet transfer equipment, replies one or more type of information related to the packet transfer method. The packet transfer equipment rewrites several types of information such as the destination IP address and the destination port number according to one or more type of information obtained and transfers the received packet.
摘要:
A VPN connection method and a communication system are provided, each which can omit the setting of a firewall and the installation of a relay server and can establish communications from the outside of a firewall to the inside thereof. The internal network 2 is connected to the external network 1 via the firewall 13. The internal network 2 enables communications by an e-mail from the external network 1 (outside the firewall) to the mail server 21 in the internal network 2 (inside the firewall) or communications by telephone or radio, which is not via the firewall 3. The feature of the firewall 3 is utilized that access from the outside to the inside of the firewall through VPN connection is very difficult but the access in the reverse stream can be simply performed. Using the mail server, telephone line or radio line, the internal network 2 receives an e-mail, which requires for VPN connection from the external network 1, or control information through the telephone line. Thus, the internal network 2 sends callback for VPN connection to the e-mail transmission source. As a result, the callback allows the external network 1 to pass through the firewall 3.
摘要:
A base node (100) and a base node (101) transmit a keep alive frame broadcast by a relay node forming a communication medium (106) and a communication medium (107) from a port 1 and a port 2, monitor an arrival state of the keep alive frame at each port, and in normal operation, assume the two communication media connected to the port 1 and the port 2 as one node to expand a communication band and at failure detection, continue communication by using only a communication medium connected to a port at which no failure is detected.
摘要:
A VPN connection method and a communication system are provided, each which can omit the setting of a firewall and the installation of a relay server and can establish communications from the outside of a firewall to the inside thereof. The internal network 2 is connected to the external network 1 via the firewall 13. The internal network 2 enables communications by an e-mail from the external network 1 (outside the firewall) to the mail server 21 in the internal network 2 (inside the firewall) or communications by telephone or radio, which is not via the firewall 3. The feature of the firewall 3 is utilized that access from the outside to the inside of the firewall through VPN connection is very difficult but the access in the reverse stream can be simply performed. Using the mail server, telephone line or radio line, the internal network 2 receives an e-mail, which requires for VPN connection from the external network 1, or control information through the telephone line. Thus, the internal network 2 sends callback for VPN connection to the e-mail transmission source. As a result, the callback allows the external network 1 to pass through the firewall 3.
摘要:
An information processing system operated by an active system and a standby system can reduce the load of a status synchronizing process. In a pair of an active information processing device and a standby information processing device closest to a transmitting terminal in the information processing system, the standby information processing device is arranged closer to the transmitting terminal. In a pair of an active information processing device and a standby information processing device closest to a receiving terminal in the information processing system, the standby information processing device is arranged closer to the receiving terminal. In other pair, a standby information processing device can be arranged closer to either the transmitting terminal or the receiving terminal.
摘要:
A fast reservation protocol type ATM switching method and ATM switching equipment which are capable to suppress deterioration in transmission efficiency by reducing a cell discarding rate even in case of transmitting a huge ATM cell burst is provided. A buffer monitoring circuit monitors the number of idle slots in a buffer of an ATM switching equipment. A resource management (RM) cell processing circuit compares the number of idle slots with the total number of cells consisting an ATM cell burst contained in an RM cell locating at the top of the ATM cell burst stream when receiving the ATM cell burst from an ATM subscriber equipment. If the number of idle slots is not available for storing all cells in the ATM cell burst, the RM cell processing circuit instructs a gate circuit to pass same number of cells as idle slots available in the buffer and discard the rest of cells, and transmits a RM cell, containing information of number of cells to be retransmitted, to the ATM subscriber equipment for requesting retransmission.
摘要:
A transmitter/receiver 101 on a mobile body 10 utilizes a plurality of antennas 100. It is assumed that a plurality of the antennas 100 are distributed and arranged in a moving direction of the mobile body, and the antennas at both ends are away from each other at an extent that a distance between the antennas is not negligible as compared with an interval of the base station. A radio wave from the base station 102-1 is stronger in intensity in 100-1 than in the center, and the radio wave from the base station 102-2 is stronger in intensity in 100-2 than in the center, respectively, whereby the communication stabilization effect, which is larger as compared with the case that the antennas are locally located in the center, is expected. This enables the interval of the base station, which is broader than the conventional one, to be employed, yet both of a speed and a frequency of a hand-over process to be lowered, and in addition hereto, the bandwidth utilization efficiency, which is higher as compared with that of the conventional example, to be realized.
摘要:
A communication quality control system for deciding an optimum communication quality in a received datagram to transfer the datagram, in which not only a destination is decided according to the data of the protocol layer 3 and beneath included in the datagram, but also attribute information of communication is taken out by an attribute detecting unit, according to the information of the respective protocol layers 4, 5, 6, and 7 or one of them, and communication quality for sending the datagram is decided by a communication quality deciding unit and a connection communication quality control unit, according to the quality information of connection corresponding to the attribute information taken out.
摘要:
An ISDN remote switching unit for accommodating analogue telephone subscriber lines and ISDN digital subscriber lines comprises at least one signal converter for each of the conventional analogue subscriber so that a line signal, an address signal and tone signal of each conventional analogue subscriber are converted into a signaling system of the ISDN digital subscribers line, and a traffic concentrator connected to the signal converter and disposed remote from a host exchange station, whereby the signaling system between the remote station and the host station is unified for both the analogue telephone subscriber and the ISDN digital subscriber.