Abstract: In a network having an L2SW in which uplink VLAN is set, a transfer delay of a voice call packet is prevented. In a process of establishing a session between terminals (5), a packet transfer device (1) stores information capable of specifying a sending terminal (5-1) and a receiving terminal (5-2) and a correspondence relation (user connection information) to a connection port into a table. A SIP message of a session control packet communicated between the terminals (5) is snooped, and a destination IP address, a transmission source IP address, a destination port number, a transmission source port number, a connection port etc. are stored into the table. In a case where an RTP packet as voice data is received after the session is established, the packet transfer device (1) performs a loopback transfer or transfers it to an uplink port in accordance with the table.

Abstract: Disclosed here is a communication apparatus and method for inter-AS routing, which enables policy routing between a stub AS and an upstream AS. The policy routing includes control which is applicable only between adjacent autonomous systems (AS's). When a subject communication apparatus notifies its own AS number or advertises attribute information that includes its own AS number to a stub AS, the communication apparatus does not use its own AS number or uses the AS number of the upstream autonomous system (AS) instead of its own AS number. In addition, when relaying routing information received from one AS to another, the subject communication apparatus also relays attribute information without discarding the information, although the information is conventionally not relayed to itself.

Abstract: In a network having an L2SW in which uplink VLAN is set, a transfer delay of a voice call packet is prevented. In a process of establishing a session between terminals (5), a packet transfer device (1) stores information capable of specifying a sending terminal (5-1) and a receiving terminal (5-2) and a correspondence relation (user connection information) to a connection port into a table. A SIP message of a session control packet communicated between the terminals (5) is snooped, and a destination IP address, a transmission source IP address, a destination port number, a transmission source port number, a connection port etc. are stored into the table. In a case where an RTP packet as voice data is received after the session is established, the packet transfer device (1) performs a loopback transfer or transfers it to an uplink port in accordance with the table.

Abstract: Disclosed here is a communication apparatus and method for inter-AS routing, which enables policy routing between a stub AS and an upstream AS. The policy routing includes control which is applicable only between adjacent autonomous systems (AS's). When a subject communication apparatus notifies its own AS number or advertises attribute information that includes its own AS number to a stub AS, the communication apparatus does not use its own AS number or uses the AS number of the upstream autonomous system (AS) instead of its own AS number. In addition, when relaying routing information received from one AS to another, the subject communication apparatus also relays attribute information without discarding the information, although the information is conventionally not relayed to itself.

Abstract: An IP address translator comprising: SIP-ALG message processing unit for assigning a virtual IP address in a process of establishing a session between an IPv4 apparatus and an IPv6 apparatus via a SIP server; an address translation table for storing a relation between an IPv4 address and a virtual IPv6 address, a relation between an IPv6 address and a virtual IPv4 address, and filter information in association with each of the virtual addresses; and a processor for performing address translation on the IPv4 and IPv6 packets according to the address translation table, wherein header information of received packets is checked on the basis of the filter information before the address translation to discard a packet which does not adapt to the filter information.