Communication device and communication method of the same

摘要

In the gateway device, the global address (GA) of the host table is set to the same value, and the GA and the local port (LP) of the transfer table are respectively set to the same value. In the IP packet analysis unit, the sorting unit analyzes the packet from the WEB client and sorts the destination of the packet, the redirection unit supplies the GA and the global port (GP) to the WEB client that has made a request by the packet according to a result of analysis to perform redirection, and the translation/transfer unit analyzes the packets transmitted through the sorting unit, translates the addresses (GA/LA: local address) and the ports (GP/LP) respectively with each other and transfers the translated packets, and then the procedure after connection establishment is repeated.

主权项

1. A communication device placed between a plurality of WEB clients located in a global space and a plurality of WEB servers located in a local space, comprising:
a processor and at least one memory, configured to provide:
a host table that stores global addresses and global ports corresponding to FQDN (Fully Qualified Domain Name) including domain name, sub-domain name, and host name of the WEB servers, where the same value is set as the global address for all of the WEB servers, and different values are set as the global ports for all the WEB server;a transfer table that stores the FQDNs of the WEB servers and the global addresses and the global ports corresponding to the FQDNs, the transfer table additionally storing local addresses and local ports of the WEB servers corresponding to the stored global addresses and global ports, where the same value is set as the global address and the same value is set as the local port for all of the WEB servers, and different values are set as the global ports and local ports for all the WEB servers; andan analysis unit that analyzes packets from the WEB clients that make requests to perform HTTP (Hyper-Text Transfer Protocol) redirection and, for each request, supplies one of the global addresses and one of the global ports according to a result of the analysis, analyzes the HTTP-redirected global address, global port, local address and local port, translates the analyzed address and port, and transfers the packet based on the translated address and port, wherein the host table and the transfer table are stored in the at least one memory, wherein the analysis unit includes:
a sorting unit that determines whether a destination address of a packet supplied from one of the WEB clients has a given value of a global address and a global port provided from a WEB server that has authenticated a FQDN and sorts a supply destination of the supplied packet,a redirection unit that extracts a FQDN of the destination from the supplied packet, searches the host table for the extracted FQDN, and transmits a global address of the WEB server and a global port of WEB server acquired as a result of the search to the WEB client that made the request to perform HTTP redirection, anda translation/transfer unit that receives the packet from the sorting unit, searches the transfer table for a match with a destination global address and a destination global port of the received packet, changes the destination global address and the destination global port to a local address and a local port of the WEB server acting as the destination according to the result of the search, and transfers the changed packet to the destination WEB server, and, reversely, receives a packet from said one of the WEB servers, searches the transfer table for a match with a source local address and a source local port of the received packet, changes the source local address and the source local port to a global address and a global port of the WEB server acting as the source according to a further search result, and transfers the changed packet to the WEB client, and wherein the redirection unit includes:
a down monitoring functional block that detects whether the WEB server in the local space is down by using a command for issuing an IP packet to a host to request acknowledgement and checking whether the IP packet arrives correctly and a response is made; anda deleting functional block that deletes an entry of a corresponding FQDN in the host table and an entry corresponding to a global address in the transfer table in response to detection that the WEB server in the local space is down.