초록 ▼

When receiving a packet sent thereto from a mobile terminal that is a sending source, a subscriber packet exchange apparatus encapsulates the packet with a multicast address without acquiring information on a routing area in which another mobile terminal that is a destination is currently located fr

When receiving a packet sent thereto from a mobile terminal that is a sending source, a subscriber packet exchange apparatus encapsulates the packet with a multicast address without acquiring information on a routing area in which another mobile terminal that is a destination is currently located from a home location register, and routes the packet to another subscriber packet exchange apparatus that manages the routing area in which the destination mobile terminal is currently located. As a result, the moving object IP packet communication system can carry out the transmission of data packets between the source and destination mobile terminals while reducing the transfer delay.

대표청구항 ▼

The invention claimed is: 1. A mobile IP packet communication system comprising: a plurality of mobile terminals; a plurality of radio base stations each configured to communicate with said mobile terminals; a plurality of base station control apparatuses each configured to manage the plurality of

The invention claimed is: 1. A mobile IP packet communication system comprising: a plurality of mobile terminals; a plurality of radio base stations each configured to communicate with said mobile terminals; a plurality of base station control apparatuses each configured to manage the plurality of said radio base stations and to control radio channels; a plurality of subscriber packet exchange apparatuses each configured to manage a routing area including a plurality of said radio base stations and a single base station control apparatus and to control a transfer of packets to one of said plurality of mobile terminals; a gateway and packet data exchange apparatus connected to each of said plurality of subscriber packet exchange apparatuses and a data packet network disposed outside said mobile IP packet communication system and configured to serve as a gateway between each of said plurality of subscriber packet exchange apparatuses and said data packet network disposed outside said mobile IP packet communication system; a home location register configured to manage information regarding routing areas in which said plurality of mobile terminals are currently located, respectively; and a plurality of visitor location registers each configured to manage information regarding zones within a corresponding routing area in which said plurality of mobile terminals may be currently located, wherein when transferring a data packet destined for a first one of said plurality of subscriber packet exchange apparatuses that manages the routing area in which one of said plurality of mobile terminals, that is the destination, is currently located, said mobile IP packet communication system is configured to transmit the data packet between a second one of said plurality of subscriber packet exchange apparatuses that manages a routing area in which one of said plurality of mobile terminals, that is a sending source, is currently located and said gateway and packet data exchange apparatus, between said second one of said plurality of subscriber packet exchange apparatuses and each of said plurality of subscriber packet exchange apparatuses after copying the data packet a number of times, equal to the number of subscriber packet exchange apparatuses linked to said second subscriber packet exchange apparatus and encapsulating said copied data packets with a multicast address, without acquiring location information on a location of said destination one of said plurality of mobile terminals, and between said second one of said plurality of subscriber packet exchange apparatuses and said first one of said plurality of subscriber packet exchange apparatuses after encapsulating the data packet by adding unicast address information corresponding to said first one of said plurality of subscriber packet exchange apparatuses that is the destination of the data packet when said first one of said plurality of subscriber packet exchange apparatuses confirms that said one of said plurality of mobile terminals, that is the destination, is currently located therein. 2. The mobile IP packet communication system according to claim 1, wherein when receiving the packet encapsulated with the multicast address and destined for said destination one of said plurality of mobile terminals, said first one of said plurality of subscriber packet exchange apparatuses to which said destination one of said plurality of mobile terminals belongs decapsulates the received packet and transfers the decapsulated packet to said destination one of said plurality of mobile terminals and transmits a response message indicating that said destination one of said plurality of mobile terminals is currently located in the routing area managed thereby to said second one of said plurality of subscriber packet exchange apparatuses that is the sending source. 3. The mobile IP packet communication system according to claim 2, wherein said first one of said plurality of subscriber packet exchange apparatuses which has received the packet that is encapsulated with the multicast address to which said destination one of said plurality of mobile terminals belongs decapsulates the received packet and transfers the decapsulated packet to said destination one of said plurality of mobile terminals, and starts a timer when transmitting the response message and repeatedly transmits the response message to said second one of said plurality of subscriber packet exchange apparatuses that is the sending source until said timer expires. 4. The mobile IP packet communication system according to claim 2, wherein after encapsulating the packet that said second one of said plurality of subscriber packet exchange apparatuses has received from said source one of said plurality of mobile terminals and transferring the packet to said first one of said plurality of subscriber packet exchange apparatuses to which said destination one of said plurality of mobile terminals belongs, said second one of said plurality of subscriber packet exchange apparatuses provides a status notification region for notification of communication status in a header region of each following packet to be transmitted in advance, and when receiving the response message from said first one of said plurality of subscriber packet exchange apparatuses to which said destination one of said plurality of mobile terminals belongs, said first one of said plurality of subscriber packet exchange apparatuses that is the destination is notified that said second one of said plurality of subscriber packet exchange apparatuses has already received the response message by using the status notification region of each following packet to be transmitted. 5. The mobile IP packet communication system according to claim 1, wherein when said destination one of said plurality of mobile terminals transmits a packet to said source one of said plurality of mobile terminals and when said first one of said plurality of subscriber packet exchange apparatuses that is a destination transmits a response message indicating that said destination one of said plurality of mobile terminals is currently located in the routing area managed thereby to said second one of said plurality of subscriber packet exchange apparatuses that is a sending source, said first one of said plurality of subscriber packet exchange apparatuses transfers the packet from said destination one of said plurality of mobile terminals to said source one of said plurality of mobile terminals by superimposing information corresponding to the response message on the packet. 6. The mobile IP packet communication system according to claim 1, wherein when transferring the packet received from said source one of said plurality of mobile terminals to either said first one of said plurality of subscriber packet exchange apparatuses to which said destination one of said plurality of mobile terminals belongs or an external packet data network to which a fixed terminal that is a destination belongs, said second one of said plurality of subscriber packet exchange apparatuses determines whether the packet is destined for either said destination one of said plurality of mobile terminals or said fixed terminal, encapsulates the packet with the multicast address when the packet is destined for said destination one of said plurality of mobile terminals, and transfers the packet to said first one of said plurality of subscriber packet exchange apparatuses to which said destination one of said plurality of mobile terminals belongs. 7. The mobile IP packet communication system according to claim 1, wherein when transferring the packet received from said source one of said plurality of mobile terminals to either said first one of said plurality of subscriber packet exchange apparatuses to which said destination one of said plurality of mobile terminals belongs or an external packet data network to which a fixed terminal that is a destination belongs, said second one of said plurality of subscriber packet exchange apparatuses encapsulates the packet with the multicast address without determining whether the packet is destined for either said destination one of said plurality of mobile terminals or said fixed terminal, and, when receiving the packet encapsulated with the multicast address and destined for said fixed terminal that is a destination, said gateway and packet exchange apparatus transfers the received packet to said fixed terminal that is a destination after decapsulating the packet and transmits a response message indicating that said fixed terminal is connected with a network managed thereby to said second one of said plurality of subscriber packet exchange apparatuses that is a sending source. 8. The mobile IP packet communication system according to claim 1, wherein when transferring the packet received from said source one of said plurality of mobile terminals to either said first one of said plurality of subscriber packet exchange apparatuses to which said destination one of said plurality of mobile terminals belongs or an external packet data network to which a fixed terminal that is a destination belongs, said second one of said plurality of subscriber packet exchange apparatuses determines whether the packet is destined for either said destination one of said plurality of mobile terminals or said fixed terminal, and encapsulates the packet with the multicast address and transfers the packet without acquiring the location information on the location of said destination one of said plurality of mobile terminals from either said home location register or said corresponding visitor location register when determining that the packet is destined for said destination one of said plurality of mobile terminals and that the packet is to be transmitted through real-time packet communications. 9. The mobile IP packet communication system according to claim 7, wherein when receiving the packet encapsulated with the multicast address and destined for said fixed terminal that is a destination, said gateway and packet exchange apparatus decapsulates the received packet and transfers the decapsulated packet to said fixed terminal, and starts a timer when transmitting the response message and repeatedly transmits the response message to said second one of said plurality of subscriber packet exchange apparatuses that is a sending source until said timer expires, or repeatedly transmits the response message to said second one of said plurality of subscriber packet exchange apparatuses that is a sending source until being notified that said second one of said plurality of subscriber packet exchange apparatuses has already received the response message through a status notification region located in a header region of each following packet transmitted thereto. 10. The mobile IP packet communication system according to claim 1, wherein when a fixed terminal that is a destination transmits a packet to said source one of said plurality of mobile terminals when said gateway and packet exchange apparatus transmits a response message indicating that said fixed terminal is connected with a network managed thereby to said second one of said plurality of subscriber packet exchange apparatuses that is a sending source, said gateway and packet exchange apparatus transfers the packet from said destination fixed terminal to said source one of said plurality of mobile terminals by superimposing the response message on the packet. 11. The mobile IP packet communication system according to claim 2, wherein either said first one of said plurality of subscriber packet exchange apparatuses or said gateway and packet exchange apparatus, which has received the packet encapsulated with the multicast address and destined for destination terminal equipment, decapsulates the received packet and transfers the decapsulated packet to said destination terminal equipment, and transmits an RSVP reserve message, as the response message, to said second one of said plurality of subscriber packet exchange apparatuses that is a sending source so as to reserve a band. 12. The mobile IP packet communication system according to claim 2, wherein either said first one of said plurality of subscriber packet exchange apparatuses or said gateway and packet exchange apparatus, which has received the packet encapsulated with the multicast address and destined for destination terminal equipment, decapsulates the received packet and transfers the decapsulated packet to said destination terminal equipment, and transmits an MPLS LDP message, as the response message, to said second one of said plurality of subscriber packet exchange apparatuses that is a sending source so as to set a virtual path.