JP2003163679A - Communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seamless communication system capable of realizing seamless communication environment and providing personal mobility by continuously using an IP address even if an access network is different between a plurality of user terminals to be used by individual persons. <P>SOLUTION: When a user terminal becomes communicable with another communication network at a moving destination and this is detected in step S42, communication medium selection information concerning the communication network is generated in a step S43. The user terminal decided, in step S44, whether to switch an access network on the basis of this communication medium selection information. When switching, a medium characteristic IP address (MIP) characteristic to the communication network is received in step S43. In steps S46 and S47, the user terminal respectively informs a user management server and an opposite terminal of the personal IP address (PIP) of himself/ herself and a medium characteristic IP address. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless communication system capable of seamlessly continuing communication over a plurality of communication networks, and particularly when a common IP address is used to switch access networks or user terminals. The present invention relates to a seamless communication system capable of seamlessly continuing communication even when changing trains.

[0002]

2. Description of the Related Art In recent years, various high-speed communication networks have become available in offices and homes. For example,
A conventional PSTN (Public Swing) is used as a wired communication network.
itched Telephone Network) and ISDN (Integrated Serv)
In addition to dial-up access via ices Digital Network, ADSL (Asymmetric Digital Subscriber Lin)
e) and FTTH (Fiber To The Home) exist. As a wireless communication network, PHS (Personal Handyphone System) and I
MT-2000 (International Mobile Telecommunicati
on 2000) and FWA (Fixed Wireless Ac)
cess) etc. exist. There is also a mode in which a wireless LAN (Local Area Network) is used at the end of a wired access network such as FTTH, and the user terminal accesses via the wireless LAN.

As described above, it has become possible for a user to select an optimum communication network from various accessible communication networks according to time and place, a desired communication speed, or the like. Here, with the recent spread of the Internet, the communication protocol is basically IP (Internet Protocol).
otocol) is used.

Conventional IP is intended for fixed user terminals, but IET is used so that moving user terminals can continue communication even in different subnets to which they have moved.
Mobile IP was specified by F (Internet Engineering Task Force). Mobile IP is an extension of existing IP to add mobility. IP version 4
It is specified for both (described as IPv4) and IP version 6 (described as IPv6). At present, application in mobile communication networks is under consideration.

In mobile IP, as shown in FIG. 5, a user terminal is given a home address in a network (home network) to which it is originally connected. When moving to a network (foreign network) other than the home network, the fact that the subnet is different is grasped by an advertisement message or the like periodically broadcast from the foreign agent FA of the foreign network. The user terminal is
Get the care-of address COA in that subnet,
This care-of address COA is registered in the home agent HA existing in the home network.

The packet transmitted from the communication partner is first transmitted to the home agent HA, and then encapsulated and transferred from the HA to the care-of address COA. This packet is received on behalf of an agent (foreign agent FA) existing in the foreign network, and finally the user terminal receives the original packet after decapsulation. The FA function may exist in the user terminal or another node in the foreign network. Also, the HA notifies the COA to the communication partner so that the communication partner can directly transfer the packet to the user terminal instead of the HA. This is called route optimization.

[0007]

Mobile IP is a technique for allowing one moving user terminal to continuously use the same IP address even in a destination network having a different address system. , The continuous use of the IP address among the plurality of user terminals used by individuals is not intended. Further, the IP address given in the home network is for identifying the user terminal, and does not provide personal mobility, which is a concept of treating an individual, not the user terminal, as an end point of communication.

An object of the present invention is to solve the above-mentioned problems of the prior art and to enable seamless use of IP addresses between a plurality of user terminals used by individuals even if the communication networks are different. Another object of the present invention is to provide a seamless communication system that can realize various communication environments and can also provide personal mobility.

[0009]

In order to achieve the above object, the seamless communication system of the present invention is characterized in that an integrated network for integrating existing wireless communication networks and wired communication networks is provided.
It has one feature.

In addition, a common personal IP address is given not to each user terminal but to each user terminal group used by the user so that the communication traffic transmitted and received by each user includes all the personal IP addresses. There is a second feature.

Further, a third characteristic is that a user management server is provided in the integrated network to manage the movement of each user terminal over a plurality of communication networks.

According to the first feature, since the existing wireless access network or wired access network owned by the communication carrier can be used as it is, seamless communication can be realized at low cost and communication traffic can be realized. Can be distributed among access networks.

According to the second feature, IP addresses can be continued between different user terminals, and personal mobility based on the personal IP address can be realized. In addition, it becomes easy for the communication carrier to manage the communication traffic generated in each communication network by the user terminal group and manage the charging and the like for each user.

According to the third feature, regardless of whether the communication network is wireless or wired, the communication network being accessed and its media unique IP address are centrally managed, and the packet route is controlled. be able to.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. In this embodiment, it is assumed that IP version 6 and mobile IPv6 are available.

FIG. 1 is a diagram showing a configuration example of a network to which the present invention is applied, in which m wireless communication networks 201-
1-201-m and n wired communication networks 202-1 and 202-1
Including 02-n. The integrated wireless / wired network 205 integrates the wireless communication networks 201 and the wired communication network 202, and may be connected to another communication network such as the Internet.

The user terminals 211 and 212 are under the control of the same user and are connectable to the respective communication networks 201 and 202. A user is a unit of terminal management in this system and may be an individual or an organization. In the following, the user terminal 21
It is assumed that 1 and 212 are owned by the same user.

Each user terminal 211 belonging to the same user,
The personal IP address that is unique and the same in all communication networks is assigned to 212 in advance. The radio
In the wired integrated network 205, a user management server 231 that manages the movement of each user user terminal between networks is installed. A plurality of user management servers 231 may be physically installed.

When the user terminal 211 is used to communicate with another user terminal (partner terminal) via any one of the communication networks, the accessed communication network sends the user terminal 211 the personal IP address. Separately, a unique media IP address is assigned to the communication network. This may be statically assigned in advance, or IPv4
6 may be dynamically assigned by a method such as the stateless automatic address setting provided in 6.

FIG. 2 is a diagram showing the structure of the header of the IPv6 packet. Here, only the fields necessary for explaining the present invention are shown, and the other fields are omitted.

In this embodiment, the routing header and the destination option header of the IPv6 extension header are used. IP transmitted from user terminals 211 and 212
In the packet, personal IP in the destination option header
Addresses are superimposed. On the other hand, the user terminals 211 and 21
In the IP packet transmitted to 2, the media unique IP address is set in the destination address field, and the personal IP address is superimposed on the routing header field.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. In step S41, the user uses the user terminal 211 to access the wireless communication network 2
The communication via 01-1 is started, and then the user terminal 2
Consider the case where 11 moves to another location. At the destination, for example, it becomes possible to communicate with the wireless LAN access point 221 connected to the wired communication network 202-n via the interface conversion device 222, which is step S.
When it is detected in 42, in step S43, communication media selection information regarding the wired communication network 202-n is generated. This communication media selection information includes the communication network 2
At least one of 02-n communication speed, line quality, communication charge, and congestion status is included.

The communication media selection information is the user terminal 21.
1 may be previously stored as internal information for each communication network, or may be acquired each time by communicating with the user management server 231. In step S44,
Based on this communication media selection information, it is determined whether or not the access network is switched from the current wireless communication network 201-1 to the wired communication network 202-n.

When switching the access network, in step S45, the media unique IP address (MIP) unique to the communication network 202-n transmitted from the wired communication network 202-n is received. In steps S46 and S47, the user terminal 211 notifies the user management server 231 (S46) and the partner terminal (S47) of its own personal IP address (PIP) and the received media unique IP address.

Thereafter, the partner terminal is the user terminal 211.
Personal IP address and new media-specific I
Since the P address can be recognized, the packet can be reliably transferred to the user terminal 211 accommodated in the wired communication network 202-n.

In this embodiment, since the personal IP address is recognized as an IP address in the transport layer and above, even if the access network is switched, T
A session such as CP (Transmission Control Protocol) is not disconnected. However, the user terminal 211 also receives an IP packet via the wireless communication network 201-1 until the partner terminal detects a change in the media unique IP address.

Therefore, in the present embodiment, as shown in FIG. 4, each user terminal has a plurality of (two in the present embodiment) communication functions, and the access networks are the communication networks 201-1 to 202. When switching to −n, one communication function continues communication with the communication network 201-1 while the other communication function starts communication with the communication network 202-n, and then a packet received by one communication function. To the other communication function.

As described above, in the present embodiment, even after the switching process is completed, the packet transferred from the access network before switching is not discarded, and is passed to the upper layer via the IP protocol processing unit after switching, I try to prevent packet loss.

According to this embodiment, the user terminal can perform seamless communication based on the personal IP address even when the access network is switched from one communication network to another communication network.

On the other hand, in step S51, the existence of the user terminals 212 belonging to the same user is determined to be Blue
When detected using an appropriate communication means such as oooth, in step S52, communication medium selection information is generated by communication with the user terminal 212 or communication with the user management server 231. This communication media selection information includes
At least one of the identification information of the communication network (the communication network 202-n in this embodiment) to which the user terminal 212 is connected, the communication speed of the communication network, the line quality, the communication charge, and the congestion status is included. In step S53, an appropriate user terminal is selected based on this communication media selection information.

In step S53, the user terminal 211 changes the user terminal from the current user terminal 211 to another user terminal 212 based on this communication media selection information.
It is determined whether to switch to. When switching the user terminal, the wireless L is transmitted from the user terminal 211 until then.
Communication that went through AN (wireless communication network 201-1)
The communication is switched from the user terminal 212 to the communication via the wired communication network 204 that passes through the interface conversion device 222 via the wired LAN.

At this time, if the user terminal 212 has already acquired the media unique IP address of the wired communication network 202-n and is in a communicable state, the user terminal 212.
Sets the media unique IP address in step S5.
At 4, 55, the user management server 231 and the partner terminal are notified, respectively.

After that, the partner terminal is the user terminal 212.
Personal IP address and new media-specific I
Since the P address can be recognized, the packet can be reliably transferred to the user terminal 212 accommodated in the wired communication network 202-n.

As described above, according to the present embodiment, even when the same user switches the user terminal from one user terminal to another user terminal, seamless communication based on the personal IP address becomes possible.

In the present embodiment, each user terminal transfers a packet to another user terminal so that the packet that has arrived at the original user terminal 211 after the terminal switching will not be discarded and lost. As an example, a communication unit such as Bluetooth is provided, and when the usage terminal is switched from the user terminal 211 to the user terminal 212, the communication by the user terminal 212 is started while continuing the communication by the user terminal 211, and thereafter, the user terminal 211. Are forwarded to the user terminal 212.

Further, when the partner terminal does not know the media unique IP address, the user management server temporarily takes in a packet having the personal IP address as the destination address. The user management server 231 holds the media-specific IP address of the communication network being accessed by each user terminal in communication, so when a packet having a personal IP address as a destination address is captured, it is encapsulated and media-specific. Not only is it transferred to the IP address, but the other terminal is notified of this relationship. Therefore,
The user management server 231 functions as a home agent in mobile IP. However, in communication within the same access network, it is not necessary to go through the user management server.

In the above-described embodiment, the description has been made assuming that both the wireless communication network and the wired communication network exist, but the same can be applied to a communication network group including only the wireless communication network or only the wired communication network. Further, in the above-described embodiment, the present invention has been described by taking IPv6 as an example.
Also in the above, the same function can be realized by encapsulating the packet including the personal IP address.

[0038]

According to the present invention, the following effects are achieved. (1) The user terminal can perform seamless communication based on the personal IP address even when moving from one access network to another access network. (2) Even if the same user switches the usage terminal from one user terminal to another one, the personal IP
Enables seamless communication based on addresses. (3) Since each user terminal belonging to the same user is assigned a unique and identical personal IP address within the communication network group, it is possible to perform mobility management and accounting management in units of personal IP address. (4) The user can select the most suitable access network at that time and start communication depending on the location, communication charge, existing terminals, and the like.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a network to which the present invention is applied.

FIG. 2 is a diagram showing a structure of a header of an IPv6 packet.

FIG. 3 is a flowchart showing the operation of this embodiment.

FIG. 4 is a block diagram showing a configuration of a user terminal.

FIG. 5 is a diagram showing a mobile IP network configuration.

[Explanation of symbols]

201 (201-1 to 201-m) ... Wireless communication network, 20
2 (202-1 to 202-n) ... Wired communication network, 205 ...
Wireless / wired integrated network, 211, 212 ... User terminal, 22
1 ... Wireless LAN access point, 222 ... Interface conversion device, 231 ... User management server

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoki Fukuya             2-15-1 Ohara, Kamifukuoka City, Saitama Stock             Company CAD Research Institute (72) Inventor Hideyuki Shinonaga             2-15-1 Ohara, Kamifukuoka City, Saitama Stock             Company CAD Research Institute F-term (reference) 5K030 GA02 GA04 HA08 HA11 HB14                       JT03 JT09 KA15 LB05 MD09                 5K033 CB08 DA02 DA19 DB18 EA03                       EC03                 5K051 AA08 BB02 CC07 DD15 EE01                       FF01 GG02 HH17 HH27 JJ04

Claims (9)

[Claims] 1. An integrated network that integrates a plurality of communication networks, a plurality of user terminals that can access each communication network, and a user management server that is provided in the integrated network and that manages inter-network movement of each user terminal. And a means for assigning a unique and identical personal IP address in the plurality of communication networks to at least one user terminal managed by the same user, and a user terminal accessing each communication network, A seamless communication system comprising means for assigning a unique media unique IP address in each communication network, and communicating with a partner terminal based on the personal IP address and the media unique IP address. 2. The seamless communication system according to claim 1, further comprising means for registering a personal IP address and a media unique IP address assigned to the user terminal in the user management server. 3. The seamless communication system according to claim 2, further comprising means for notifying the partner terminal of the media unique IP address assigned to the user terminal. 4. The user management server is a personal I
2. A packet, to which a P address is added but a media unique IP address is not added, is fetched, and the packet is transferred with a media unique IP address corresponding to the personal IP address as a care-of address. 4. The seamless communication system according to any one of 1 to 3. 5. The seamless communication system according to claim 1, wherein the media unique IP address is used as routing control information of an IP packet to a user terminal. 6. When the user terminal newly recognizes another accessible communication network, the communication speed of the communication network,
6. The seamless communication system according to claim 1, wherein communication medium selection information including one or more of line quality, communication charge, and congestion status is acquired from the user management server. 7. The user terminal, when newly recognizing another user terminal that can be changed, a communication network accessible from the other user terminal, a communication speed of the communication network, a line quality, a communication charge, and 6. The seamless communication system according to claim 1, wherein communication medium selection information including one or more congestion states is acquired from the user management server. 8. The user terminal has a plurality of communication functions, and when the access network is switched from one communication network to another communication network, communication with the one communication network is continued with one communication function. However, the communication with another one communication network is started by the other one communication function, and then the packet received by the one communication function is transferred to the other one communication function.
6. The seamless communication system according to any one of 5 to 5. 9. The user terminal has a transfer function for transferring a packet to another user terminal, and when switching from one user terminal to another user terminal, while continuing communication by the one user terminal 6. The communication is started by another one user terminal, and then the packet received by the one user terminal is transferred to the other one user terminal by using the transfer function. The seamless communication system according to any one of 1.