Electrical computers and digital processing systems: multicomput – Computer-to-computer session/connection establishing
Reexamination Certificate
1998-08-03
2003-07-01
Burgess, Glenton B. (Department: 2153)
Electrical computers and digital processing systems: multicomput
Computer-to-computer session/connection establishing
C709S228000, C709S220000, C709S221000, C709S245000, C370S331000, C370S338000, C455S433000
Reexamination Certificate
active
06587882
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mobile IP communication scheme, and more particularly, to a mobile computer device capable of carrying out communications while moving over a plurality of inter-connected networks, a mobile computer management device and a mobile information management device for protecting necessary information to the mobile computer device and relaying data packets transmitted to the mobile computer device according to the need, and a communication control method used by these devices.
2. Description of the Background Art
In conjunction with availability of a computer system in smaller size and lower cost and a more enriched network environment, the use of computer system has been rapidly expanded into variety of fields, and there is also a transition from a centralized system to a distributed system. In this regard, in recent years, because of the advance and spread of the computer network technology in addition to the progress and improved performance of the computer system itself, it has become possible to realize not only a sharing of resources such as files and printers within an office but also communications (electronic mail, electronic news, file transfer etc.) with outside of an office or organization, and these communications are now widely used.
In particular, in recent years, the use of the world's largest computer network called Internet has become very popular, and there are new computer businesses for connecting to the Internet and utilizing open information and services, or for providing information and services to external users who make accesses through the Interest. In addition, new technological developments are made in relation to the use of the Internet.
Also, in conjunction with the spread of such networks and the advance of small portable terminal technology, there are technological developments regarding the mobile computing. In the mobile computing, a user carries along a portable computer or terminal and makes communications while moving over networks and there is a need for a scheme that manages a changing address of a mobile computer on a network during such a communication in order to route the communication content correctly. As a protocol for supporting such mobile communications, there is a scheme called mobile IP which is currently in a process of being standardized by the mobile-IP working group of the IETF (see IETF RFC2002, IP mobility support (C. Perkins)).
In the mobile IP, a module (home agent) for managing a location information of the mobile computer is provided in a network to which the mobile computer originally belongs, and when the mobile computer moves, the mobile computer sends a registration message indicating a current location to this home agent. When this registration message is received, the home agent carries out a routing control in which the home agent acquires data destined to the mobile computer that is transmitted to an original address (home address) of the mobile computer and transfers it to the current location of the mobile computer automatically by encapsulating it inside a packet destined to the registered current location address of the mobile computer.
FIG. 19
shows this situation where a home agent (HA)
105
is playing this role with respect to a mobile computer
102
. Namely, when the mobile computer
102
moves from a home network
1
a
to a network
1
b,
the mobile computer
102
sends a registration message indicating a current location to the home agent
105
, and the home agent
105
that received this registration message carries out a control for transferring data transmitted to the original address (home address) of the mobile computer
102
to the current location of the mobile computer
102
.
Now, in the case of carrying out a communication from a visited site using this mobile IP scheme, the mobile computer will always receive data through the home agent of the home network. However, when the mobile computer moves far away from the home agent, there is a possibility for considerably lowering the performance of a communication program because packets are always routed via the home agent. This is the case not only when the physical distance between the visited site network and the home network is large but also when a route between the visited site network and the home network involves a path at which many data packets are jamming.
Namely, the communication method using the mobile IP has a scalability that guarantees a continual communication regardless of a location on the IP network to which the mobile computer moves, but it does not necessarily guarantee that the communication can be continued comfortably.
Also, another advantage of the mobile IP scheme is that it is possible to make accesses to various resources of the home site by using attributes given before moving, because accesses are made by packets originating from an address in the home network (home address) even when the mobile computer is located at the visited site. However, in general, in the case of making an access to an information unrelated to the home site (as in the case of making an access to a Web page on the third party network or to a local printer at the visited site, for example), there is no need to carry out communications via the home network using the mobile IP, and it suffices to just use an address (temporal address) that is temporarily assigned at the visited site.
Yet, there are some recent network communication softwares in which a proper communication cannot be realized by just acquiring a temporal address alone at the visited site. For example, at a site where a network is constructed using private addresses, an address conversion is carried out by using a server called proxy server at a time of making an access to an external site, so that it is necessary for the communication software to make a setting of an IP address of the proxy server. Also, in the case where a DNS (Domain Name System) server is provided at each site, the use of the DNS server can be convenient as it becomes possible to make an access to a resource using a host name rather than an IP address, but in such a case it is also necessary to make a setting of an IP address of the DNS server in address.
In other words, in the case of trying to receive a network service using a temporal address borrowed from some network, without using the mobile IP, it is necessary to obtain a resource information (such as that of the proxy server or the DNS server mentioned above) of that network. Such an information is freely obtainable for a network manager in general, but for a general user, it is difficult to handle such an information and it is also difficult to make a proper setting of such an information at a proper portion of the communication program.
As described above, in general, in the case of supporting a mobile computer using the mobile IP scheme, communications with a home agent of a home network can be very difficult depending on a moved location of the mobile computer, and this fact can adversely affect the operation performance of a communication program in some cases.
On the other hand, when a scheme for acquiring a temporal address at a visited site and using it in carrying out communications is adopted, it becomes necessary to obtain various kinds of network configuration information (such as that of a proxy server or a DNS server in the case of WWW access, or that of a Certificate Server in the case of SSL (data encryption) communication, for example), besides an address. In order to make a proper setting of such an information, a thorough understanding of a network environment at a visited site is required so that it is quite difficult to do for a beginner who has no knowledge regarding networks.
Thus, conventionally, in the case of using a program such a browser while moving over networks, it has been necessary to make a proper setting of various kinds of environmental information in addition to acquiring an IP address at a visited site, and it has been ve
Fukumoto Atsushi
Inoue Atsushi
Ishiyama Masahiro
Tsuda Yoshiyuki
Burgess Glenton B.
Edelman Bradley
Foley & Lardner
Kabushiki Kaisha Toshiba
LandOfFree
Mobile IP communication scheme using visited site or nearby... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Mobile IP communication scheme using visited site or nearby..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mobile IP communication scheme using visited site or nearby... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3019686