Patent ID: 8995264
Filing Date: 2015-03-31
Classification: H04L

Abstract:
1. A packet transfer device for transferring packets between a plurality of private networks and a global network, the packet transfer device comprising: first means for allocating a global address to a plurality of private addresses of the plurality of private networks, converting address information and a port number included in a header of a received packet, and transferring the received packet to a destination having the converted address information and port number; and second means, including a session management table in which a number of available sessions between a user terminal in the plurality of private networks and a device in the global network is set for each of a plurality of groups including one or more private addresses, for managing the number of current sessions between the user terminal and the device in the global network such that, when the number of sessions of the user terminal is greater than the number of available sessions which is set for the group to which the user terminal belongs, the excess number of sessions is restricted, wherein the second means restricts sessions of the user terminal when the number of current sessions is greater than the number of available sessions for that group, wherein the session management table includes an allocation range of port numbers available to each group of the plurality of groups, wherein the second means arbitrarily determines a port number from the allocation range when the number of current sessions between the user terminal and the device in the global network is not greater than the available session numbers for the group to which the user terminal belongs, and wherein the first means performs an address conversion of the address information and the port number based on the port number determined by a session restriction unit.