Patent Application
20070217364
The present invention relates to an access network system, a connection station device, a radio base station device, and a packet loss reducing method for achieving mobility control in Wide-Area Ethernet™.
In the past, a mobile IP has been adopted for mobility control in IP network. The mobile IP is a technique, by which communication can be carried out by the same IP address regardless of the network, to which the mobile terminal is connected. A home agent in charge of the management of position of the mobile terminal (hereinafter, also referred as “HA”) receives a packet instead of the mobile terminal and transfers it to the mobile terminal. When the mobile terminal moves in a network during communication, the change of network address is notified and the destination of the transfer of the packet is changed. However, during the time from the change of the network address of the mobile terminal to the notification of the change to HA, the packet to the mobile terminal is transferred to the network before moving, and it is abandoned. Specifically, when communication distance between the mobile terminal and HA is long, more time is required for the handover, and the amount of the packet loss increases accordingly. For this reason, a fast changeover method is proposed, which is based on the changeover of the tunnel using label in the access network to connect user with ISP (Internet Service Provider) for the purpose of speeding up the handover. This fast changeover method is disclosed in the Non-Patent Document 1 as given below. According to this method, signaling time is reduced by the signaling closed in access net, and a label independent from IP address is used. As a result, the processing to change IP address can be eliminated, and fast handover can be achieved compared with mobile IP. Also, the Non-Patent Document 2 as given below discloses a method, in which mobile terminal has temporarily both the network address before moving and the network address after moving as extension of the mobile IP, and access router (AR) copies and transfers the packet to both of the network addresses temporarily.
However, when the method to changeover the path to high speed by using VLAN (Virtual LAN) path as described in the Non-Patent Document 1, fast changeover can be performed without the processing such as the change of IP address, and the time for changeover can be reduced, while there remains a problem that packet loss occurs until the changeover of path is completed after moving to new area (link changeover) at the time of path changeover. More concretely, after MN (mobile terminal) 1500 moves to a new area as shown in
According to this method, as shown in
To solve the above problems, it is an object of the present invention to provide an access network system, a connection station device, a radio base station device and a packet loss reducing method, by which it is possible to reduce the packet loss during the handover of the mobile terminal and to eliminate wasteful consumption of the band.
To attain the above object, the present invention provides an access network system, which comprises a mobile terminal, a connection station device connected with an external IP network to relay the communication between said mobile terminal and said external IP network, to which said mobile terminal belongs, a relay station device connected to said connection station device and for relaying a packet transmitted from said external IP network to said mobile terminal via said connection station device, a plurality of radio base station devices connected to said relay station device and said mobile terminal and for receiving said packet relayed by said relay station device from said relay station device and for transferring to said mobile terminal, and for transferring the packet from said mobile terminal to said relay station device in order to transmit to said external IP network, and a network management unit to make up a VLAN path between said connection station device and said radio base station device, wherein said radio base station where said mobile terminal are connected and said connection station device generates own MAC addresses based on identification information assigned to said mobile terminals as notified from the network management unit; said network management unit arranges, when said mobile terminal starts handover, a point-to-multipoint VLAN path by adding said new radio base station device to a point-to-point VLAN path between said previous radio base station device where said mobile terminal has been connected before the start of said handover and said connection station device, and said connection station device encapsulates packet received from said external IP network side by adding a new MAC header with a broadcast address for a destination MAC address and with the MAC address of said connection station device for a source MAC address, and adding an identification information of said mobile terminal starting the handover, and transfers the encapsulated packet via said point-to-multipoint VLAN path. With this arrangement, the same packet can be transferred to a plurality of radio base station devices without performing special packet duplication by using efficient tree configuration while using normal layer 2 switch in the relay station device.
Also, according to the preferred aspect of the present invention, the access network system as described above is provided, wherein each MAC address generated at said connection station device and said radio base station where said mobile terminal is connected is processed by mapping to said identification information of said mobile terminal on 1:1 basis and also include a specific ID to indicate said connection station device or said radio base station where said mobile terminal is connected. With this arrangement, when packet can be encapsulated, MAC address of the partner can beautomatically generated, and there is no need to use a protocol to inquire MAC address of the partner.
Further, according to the preferred aspect of the present invention, the access network system as described above is provided, wherein said connection station device transfers the encapsulated packet by using a broadcast address to the destination MAC address when a difference between electric field intensity received from said previous radio base station device and electric field intensity received from said new radio base station device is equal to or lower than a predetermined value after said point-to-multipoint VLAN path has been made up by said network management unit, and in other cases, transfers the encapsulated packet by using a unicast address of the radio base station device with high electric field intensity as the destination MAC address. With this arrangement, it is possible to efficiently transfer the packet.
Also, according to the preferred aspect of the present invention, the access network system as described above is provided, wherein said network management unit prunes a branch part of said VLAN path between said connection station device and said previous radio base station device when said handover of said mobile terminal has been completed. With this arrangement, there is no need to maintain VLAN path, which is not required any more.
Also, according to the preferred aspect of the present invention, the access network system as described above is provided, wherein said previous radio base station device deletes said own MAC address corresponding to identification information of said mobile terminal after completion of said handover of said mobile terminal. With this arrangement, there is no need to maintain MAC address, which is not required any more.
Further, according to the preferred aspect of the present invention, the access network system as described above is provided, wherein said connection station device encapsulates packet by adding a MAC header with said unicast MAC address of said radio base station device, where said mobile terminal is connected, as destination MAC address, and said own MAC address as source MAC address, and by adding said identification information corresponding to said mobile terminal to said packet received from said external IP network side except during said handover of said mobile terminal, and transfers said encapsulated packet via said point-to-point VLAN path between said connection station device and said radio base station device where said mobile terminal is connected. With this arrangement, there is no need to perform broadcast transfer except the time during handover, and the load to perform useless processing can be reduced.
Also, according to the preferred aspect of the present invention, a connection station device in the access network system as described above is provided, wherein said access network system comprises a mobile terminal, a connection station device connected with an external IP network to relay the communication between said mobile terminal and said external IP network, to which said mobile terminal belongs, a relay station device connected to said connection station device and for relaying a packet transmitted from said external IP network to said mobile terminal via said connection station device, a plurality of radio base station devices connected to said relay station device and said mobile terminal and for receiving said packet relayed by said relay station device from said relay station device and for transferring to said mobile terminal, and for transferring the packet from said mobile terminal to said relay station device in order to transmit to said external IP network, and a network management unit to make up a VLAN path between said connection station device and said radio base station device(s), wherein said connection station device comprises MAC address generating means for generating a plurality of own MAC addresses based on identification information assigned to said mobile terminal as notified from said network management unit, receiving means for receiving a packet from said external IP network side to said mobile terminal, judging means for judging whether said mobile terminal is during handover or not, encapsulating means for encapsulating packet by adding a new MAC header with a broadcast address for a destination MAC address and with own MAC address generated by said MAC address generating means for source MAC address, and adding an identification information of said mobile terminal starting the handover to said packet received by said receiving means when it is judged that said mobile terminal is during handover by said judging means, and transfer means for transferring said packet encapsulated by said encapsulating means via a point-to-multipoint VLAN path made up by said network management unit between said radio base station device where said mobile terminal has been connected before said handover and own device, and also between said radio base station device where said mobile terminal will be connected after said handover and own device when said mobile terminal starts the handover. With this arrangement, soft handover can be efficiently carried out on a system using VLAN path.
Further, according to the preferred aspect of the present invention, a connection station device in the access network system as described above is provided, wherein said MAC address generating means generates MAC address processed by mapping to said identification information of said mobile terminal on 1:1 basis and also including a specific ID to indicate own device. With this arrangement, MAC address of the partner can be automatically generated at the encapsulation of the packet, and there is no need to use a protocol to inquire MAC address of the partner.
Also, according to the preferred aspect of the present invention, a connection station device in the access network system as described above is provided, wherein said encapsulating means encapsulates packet by adding a MAC header with said unicast MAC address of said radio base station device, where said mobile terminal is connected, as destination MAC address, and said MAC address generated by said MAC address generating means as source MAC address, and by adding said identification information corresponding to said mobile terminal to said packet received by said receiving means when it is judged that said mobile terminal is not during handover by said judging means. With this arrangement, packet can be efficiently transferred.
Further, according to the preferred aspect of the present invention, a connection station device in the access network system as described above is provided, wherein said receiving means receives a packet from said mobile terminal via said relay station device, and said encapsulating means removes the MAC header of said packet from said mobile terminal and the identification information of said mobile terminal, and said transfer means transfers said packet where said MAC header and identification information of said mobile terminal have been removed to said external IP network when it is judged by said judging means that the packet from said mobile terminal received via said relay station device is transmitted to said external IP network via the device itself. With this arrangement, the packet from the mobile terminal can be efficiently transmitted to external IP network.
Also, according to the preferred aspect of the present invention, a radio base station device in the access network system as described above is provided, wherein a mobile terminal, a connection station device connected with an external IP network to relay the communication between said mobile terminal and said external IP network, to which said mobile terminal belongs, a relay station device connected to said connection station device and for relaying a packet transmitted from said external IP network to said mobile terminal via said connection station device, a plurality of radio base station devices connected to said relay station device and said mobile terminal and for receiving said packet relayed by said relay station device and for transferring to said mobile terminal, and for transferring the packet from said mobile terminal to said relay station device in order to transmit to said external IP network, and a network management unit to make up a VLAN path between said connection station device and said radio base station device, wherein said radio base station device comprises MAC address generating means for generating a plurality of own MAC addresses based on identification information assigned to said mobile terminal as notified from said network management unit, receiving means for receiving said packet from said external IP network encapsulated by said connection station device, judging means for judging whether the destination MAC address of MAC header of said encapsulated packet received by said receiving means is a broadcast address or a unicast address, deleting means for deleting MAC header of said encapsulated packet and identification information of said mobile terminal when said encapsulated packet is judged as a packet having said broadcast address by said judging means and when the identification information of said mobile terminal added to said packet is the same as the identification information notified from said management unit, or when said encapsulated packet is judged as a packet having said unicast address and when said unicast address is the same as one of own MAC addresses corresponding to the identification information of said mobile terminal generated by said MAC address generating means, and transfer means for transferring said packet, where MAC header and portion of identification information of said mobile terminal have been deleted by said deleting means, to said mobile terminal. With this arrangement, packet transfer can be carried out at the radio base station device without paying special attention to the handover.
Further, according to the preferred aspect of the present invention, a radio base station device in the access network system as described above is provided, wherein said MAC address generating means generates MAC address processed by mapping to said identification information of said mobile terminal on 1:1 basis and also including a specific ID to indicate own device. With this arrangement, MAC address of the partner can be automatically generated at the encapsulation of the packet, and there is no need to use a protocol to inquire MAC address of the partner.
Also, according to the preferred aspect of the present invention, a radio base station device in the access network system as described above is provided, wherein said device further comprises encapsulating means for encapsulating packet by adding a MAC header with a MAC address of said connection station device for a unicast destination address and with own MAC address for a source MAC address, and adding an identification information of said mobile terminal, to the packet received by said receiving means and to be sent to said external IP network from said mobile terminal, and said transfer means transfers said packet encapsulated by said encapsulating means to said external IP network via said relay station device. With this arrangement, the packet transmitted from the radio base station device to external IP network can be transferred to the connection station device even on a point-to-multipoint VLAN path.
Further, according to the preferred aspect of the present invention, a packet loss reducing method in the access network system as described above is provided, wherein a mobile terminal, a connection station device connected with an external IP network to relay the communication between said mobile terminal and said external IP network, to which said mobile terminal belongs, a relay station device connected to said connection station device and for relaying a packet transmitted from said external IP network to said mobile terminal via said connection station device, a plurality of radio base station devices connected to said relay station device and said mobile terminal and for receiving said packet relayed by said relay station device and for transferring to said mobile terminal, and for transferring the packet from said mobile terminal to said relay station device in order to transmit to said external IP network, and a network management unit to make up a VLAN path between said connection station device and said radio base station device, wherein said method comprising the steps of generating a plurality of own MAC addresses based on identification information assigned to said mobile terminal as notified from said network management unit by said radio base station where said connection station device and said mobile terminal are connected, constituting a point-to-multipoint VLAN path where said new radio base station device where said mobile terminal will be connected is added to a point-to-point VLAN path between said previous radio base station device where said mobile terminal has been connected before starting said handover and said connection station device, by said network management unit when said mobile terminal starts the handover, and said connection station device encapsulates packet received from said external IP network side by adding a MAC header with a broadcast address for a destination MAC address and with MAC address of said connection station device for source MAC address, and by adding an identification information of said mobile terminal starting the handover, and transfers the encapsulated packet via said point-to-multipoint VLAN path. With this arrangement, the same packets can be transferred to a plurality of radio base station devices without performing special packet duplication by using efficient tree configuration even when normal layer 2 switch in the relay station device is used.
Also, according to the preferred aspect of the present invention, a packet loss reducing method in the access network system as described above is provided, wherein each MAC address generated at said connection station device and said radio base station where said mobile terminal is connected is processed by mapping to said identification information of said mobile terminal on 1:1 basis and also includes a specific ID to indicate said connection station device or said radio base station where said mobile terminal is connected. With this arrangement, MAC address of the partner can be automatically generated at the encapsulation of packet, and there is no need to use a protocol to inquire MAC address of the partner.
Further, according to the preferred aspect of the present invention, a packet loss reducing method in the access network system as described above is provided, wherein said method further comprising the steps of transferring said encapsulated packet by using broadcast address for the destination address when a difference between electric field intensity received from said previous radio base station device and electric field intensity received from said new radio base station device is equal to or lower than a predetermined value after said point-to-multipoint VLAN path has been made up by said network management unit, and in other cases, transfers the encapsulated packet by using unicast address of the radio base station device with high electric field intensity as the destination address. With this arrangement, packet can be efficiently transferred.
Also, according to the preferred aspect of the present invention, a packet loss reducing method in the access network system as described above is provided, wherein said network management unit prunes a branch part of said VLAN path between said connection station device and said previous radio base station device when said handover of said mobile terminal has been completed. With this arrangement, there is no need to maintain VLAN path, which is not required any more.
Further, according to the preferred aspect of the present invention, a packet loss reducing method in the access network system as described above is provided, wherein said previous radio base station device deletes own MAC address corresponding to identification information of said mobile terminal after completion of said handover of said mobile terminal. With this arrangement, there is no need to maintain VLAN path, which is not required any more.
Also, according to the preferred aspect of the present invention, a packet loss reducing method in the access network system as described above is provided, wherein said connection station device encapsulates packet by adding a MAC header with said unicast MAC address of said radio base station device, where said mobile terminal is connected, as destination MAC address, and said own MAC address as source MAC address, and by adding said identification information corresponding to said mobile terminal, to said packet received from said external IP network side except during said handover of said mobile terminal, and transfers said encapsulated packet via said point-to-point VLAN path between said connection station device and said radio base station device where said mobile terminal is connected. With this arrangement, there is no need to perform broadcast transfer except the time during handover, and the load to perform useless processing can be reduced.
The access network system, the connection station device, the radio base station device, and the packet loss reducing method according to the present invention have the arrangement as described above. As a result, the packet loss during handover of the mobile terminal can be reduced and wasteful consumption of the band can be eliminated.
Description will be given below on an access network system, a connection station device, a radio base station device, and a packet loss reducing method in the embodiment of the present invention by referring to
First, description will be given on the access network system in the embodiment of the invention referring to
The access network is a network to connect the mobile terminal 100 with the ISP network 101. A subscriber of the mobile terminal 100 can connect individually to an ISP network 101 as desired. The access network logically comprises two planes. One is a transfer plane to transfer the packet from the mobile terminal 100 to the ISP network 101, and the other is a control plane to execute supervision and management of the access network. The transfer plane comprises a net using tunnel technique to transmissively transmit a layer 2 (data link layer) network in OSI model. On the other hand, the control plane comprises a layer 3 (network layer) in OSI model. It makes up an IP net closed within the access network and executes transmission of control information between devices by normal IP routing. The network management unit 106 as described above carries out management of the entire access network.
The network management unit 106 primarily manages VLAN route of the access network (hereinafter also called “VLAN path”). Here, description will be given on management of VLAN route by the network management unit 106 referring to
When the handover of the mobile terminal 100 is started, the network management unit 106 changes to a point-to-multipoint VLAN path as described later including the radio base station 104b of mobile destination (Step S206), and notifies VLANID corresponding to the mobile terminal 100 to the connection station 103 and to the radio base station 104b of mobile destination (Steps S207 and S208). Then, the connection station 103 performs encapsulation using a broadcast address (to be described later), and the encapsulated packet is transferred to the mobile terminal 100 (Step S209). The radio base station 104b of mobile destination generates and sets up MAC address to be used in own access network to match the notified VLANID (Step S210). When the handover of the mobile terminal 100 is terminated, the change of VLAN path occurs (Step S211). Then, the network management unit 106 prepares point-to-multipoint VLAN path (to be described later) between the radio base station 104b and itself and notifies the VLANID corresponding to the mobile terminal 100 to the connection station 103 and to the radio base station 104a before moving (Steps S212 and S213). As a result, the connection station 103 performs encapsulation by using a unicast address (to be described later) from the broadcast address and transfers the encapsulated packet to the mobile terminal 100 (Step S214). The radio base station 104a before moving deletes the MAC address in use by the notified VLANID (Step S215).
Next, description will be given on packet transfer during handover of the mobile terminal in the access network system according to the embodiment of the present invention by referring to
Here, description will be given on the encapsulated packet to be used in the access network system, the connection station device as described later, the radio base station device as described later and the packet loss reducing method in the embodiment of the present invention by referring to
The connection station 103 transfers the packet thus encapsulated. Here, the expression VLANID=1 means that the VLANID assigned to the mobile terminal 100 is 1, for instance. Next, description will be given on the packet to be transferred to the mobile terminal 100 during handover at the connection station 103 by referring to
Then, the connection station 103 transfers the encapsulated packet. Next, description will be given on the packet transferred to the ISP device 102 of the ISP network 101 at the radio base station 104 by referring to
In this case, with regard to the packet transmission from the radio base station 104 to the ISP device 102 of the ISP network 101, the packet is encapsulated and transferred with the same unicast address even during the handover. For this reason, even when it is the point-to-multipoint VLAN path, the packet transmitted from the radio base station 104 to the ISP device 102 of the ISP network 101 is transferred to the connection station 103, and it is not transferred to the other radio base station 104 in almost all cases. However, regarding the MAC address learning at the relay station 105, if MAC address of the matching connection station 103 is erased from the learning table by timer, the packet may be copied and transferred to the connection station 103 and the other radio base station 104 at the relay station 105. Even in this case, however, it can be confirmed that it is the packet addressed to the connection station 103 at the moment when it is checked whether the destination MAC address is registered as own MAC address or not at the radio base station 104, and it is not transferred to the mobile terminal 100.
Turning back to
The access network system in the embodiment of the present invention is characterized in that packet can be transferred from the relay station 105a to the relay station 105f by using normal Ethernet™ switch. Also, during handover, regarding the unicast packet addressed to the mobile terminal 100, a broadcast address is inserted to the destination MAC address and it is encapsulated when VLANID to indicate the path to the radio base station 104 where the mobile terminal 100 is connected is inserted at the connection station 103. In so doing, even when it is a unicast address, it can be handled as a broadcast address within the access network only during handover, and the same packet can be transferred to a plurality of radio base stations. The encapsulated packets are converted to normal packets at the radio base station 104 (remove MAC header and VLAN tag added at the connection station 103) and are transmitted to the mobile terminal 100. In this respect, the mobile terminal 100 can receive the packet from two radio base stations 104a and 104b as normal Ethernet™ frame. Even when the radio base station 104 is changed during handover, the packet can be continuously received. However, it is not essential to output the same packet from two radio base stations, and one radio base station may be selected between the mobile terminal 100 and the radio base stations 104a and 104b. Also, for the destination MAC address before handover as shown in
When handover is terminated, as shown in
Next, description will be given on a format of MAC address of the connection station 103 and the radio base station 104 to be added during the encapsulation as described above by referring to
In the meantime, in the operation of the access network system in the embodiment of the present invention, it is described that the connection station 103 and the radio base station 104 are operated respectively. However, what is actually operated is processed by the devices, which are present in the connection station 103 and the radio base station 104. In this respect, description will be given below on a concrete arrangement and operation of the connection station device of the embodiment of the present invention in the connection station 103 and the radio base station device of the embodiment of the present invention in the radio base station 104 by referring to
First, description will be given on an arrangement of the connection station device in the embodiment of the present invention by referring to
On the other hand, when the mobile terminal 100 starts the handover, the encapsulation unit 802 sets up broadcast address to the destination MAC address 601b as explained in
The transfer unit 803 transfers the packet encapsulated by the encapsulation unit 802 to the relay station 105 or transfers the packet, which the encapsulation unit 802 has received from the relay station 105 via the receiving unit 801 and from which MAC header portion and VLAN tag have been removed from the encapsulated packet, to the ISP device 102. Also, control instruction received from the unit management unit 106 via the receiving unit 801 is transferred to the relay station 105. The control unit 804 performs processing and operation necessary for adequately transferring the packet received at the receiving unit 801. Concrete processing and operation will be explained in connection with the flow chart of packet transfer processing flow as shown in
Next, description will be given on transfer processing flow of the packet received by the connection station device 800 by referring to
When it is judged that VLAN path is present, the control unit 804 judges whether the mobile terminal 100 on the corresponding VLAN path is during handover or not (Step S903). When the control unit 804 judges that the mobile terminal 100 on the corresponding VLAN path is during handover, the encapsulation unit 802 sets up a broadcast address to destination MAC address of MAC header used in encapsulation (Step S904). On the other hand, when the control unit 804 judges that the mobile terminal 100 on the VLAN path is not during handover, the encapsulation unit 802 sets up a unicast address to destination MAC address of MAC header used in encapsulation (Step S905).
The encapsulation unit 802 inserts its own MAC address to the source MAC address of MAC header where destination MAC address is set up and inserts VLANID to the VLAN tag, and encapsulates (Step S906), and the transfer unit 803 transfers the encapsulated packet to the relay station 105 (Step S907). When the control unit 804 judges that VLAN path is not present in Step S902, the packet is abandoned (Step S908).
Next, description will be given on transfer processing flow of the packet received from the relay station 105 by referring to
Next, description will be given on an arrangement of a radio base station device in the embodiment of the present invention referring to
The deleting unit 1103 deletes MAC header and VLAN tag of the encapsulated packet when the packet encapsulated by the judging unit 1102 is judged as a packet having broadcast address and a predetermined condition is met or when the encapsulated packet is a packet having unicast address and a predetermined condition is met. Here, the predetermined condition to be added when it is judged as a packet having broadcast address is a condition that VLANID of VLAN tag of the received and encapsulated packet is the same as the VLANID stored in the storage region (not shown) of the radio base station device 1100. The VLANID stored in a predetermined storage region (not shown) of its own radio base station device 1100 is a VLANID notified from the network management unit 106 as described above. Also, the predetermined condition to be added when it is judged as a packet having unicast address is a condition that the destination MAC address of MAC header of the received encapsulated packet is the same as the MAC address of its own radio base station device 1100.
The transfer unit 1104 transfers the packet, in which MAC header has been deleted by the deleting unit 1103, to the mobile terminal 100 or transfers the packet encapsulated by the encapsulation unit 1105 as described later to the relay station 105. The encapsulation unit 1105 sets up a unicast address (MAC address of the connection station 103) to the destination MAC address 601c as explained in
Next, description will be given on transfer processing flow of a packet received by the radio base station device 1100 by referring to
When the destination MAC address is judged as a unicast address by the judging unit 1102, the deleting unit 1103 judges whether the address of the destination MAC address is the same as the MAC address stored in the predetermined storage region (not shown) of its own radio base station device 1100 or not (Step S1203). When it is judged that it is the same as the MAC address stored in the predetermined storage region, MAC header and VLAN tag of the encapsulated packet are deleted (Step S1204). The transfer unit 1104 transfers the packet, from which MAC header and VLAN tag have been deleted by the deleting unit 1103, to the mobile terminal 100 (Step S1205).
On the other hand, when the destination MAC address is judged as a broadcast address by the judging unit 1102 in Step S1202, the deleting unit 1103 judges whether VLANID of VLAN tag of the received and encapsulated packet is the same as the VLANID stored in a predetermined storage region (not shown) of its own radio base station device 1100 or not (Step S1206). When it is judged that it is the same as the VLANID stored in the predetermined storage region, it is shifted to Step S1204. When it is judged in Step S1206 that it is not the same as the VLANID stored in the predetermined storage region, the control unit 1106 abandons the corresponding packet (Step S1207). If it is judged in Step S1203 that it is not the same as the MAC address stored in the predetermined storage region, the control unit 1106 abandons the corresponding packet (Step S1208).
Next, description will be given on transfer processing flow of the packet received from the mobile terminal 100 by referring to
In this case, network architecture of the access network system in the embodiment of the present invention has a configuration of a control plane by IP network and a transfer plane by the layer 2 similarly to the access network configuration model in “A Review of Mobility Control in Wide Area Ethernet™” of the Non-Patent Document 1 in the prior art.
The functional blocks used in the description of the embodiment described above can be typically achieved as LSI, i.e. an integrated circuit. These may be turned to one chip individually or into one chip including a part or all. Here, it is referred as LSI, while it may be called IC, system LSI, super LSI, or ultra LSI, depending on the difference in integration.
Also, the method to turn to the integrated circuit is not limited to LSI, and it may be actualized as a dedicated circuit or a general purpose processor. FPGA (Field Programmable Gate Array), which can be programmed after the manufacture of LSI, or a reconfigurable processor, in which the connection and the setting of the circuit cell within LSI can be reconfigured, may be used.
Further, if the technique of integrated circuit to replace LSI appears with the progress of semiconductor technique or associated technology, the integration of functional block may be carried out by using such technique. The application is possible in the field of biotechnology.
The access network system, the connection station device, the radio base station device, and the packet loss reducing method according to the present invention make it possible to reduce packet loss during handover of mobile terminal and to eliminate wasteful consumption of band. In this respect, the present invention is useful in the access network system, the connection station device, the radio base station device, and the packet loss reducing method to actualize mobility control in the Wide Area Ethernet™.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-147500 | May 2004 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP05/08720 | 5/12/2005 | WO | 4/2/2007 |
