Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1998-05-01
2001-08-21
Ton, Dang (Department: 2732)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S356000
Reexamination Certificate
active
06278712
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a technique for reserving a resource to be used in a future communication in accordance with a request from a user terminal in a network to which a plurality of switching nodes each linking a plurality of user terminals are connected. More particularly, the invention relates to a method of reserving a network resource such as a network band and a communication quality level in a computer network in which a plurality of network nodes are connected.
With improvement in computer technology and communication technology, the desire for real-time communication of audio data and video data is becoming stronger. Especially, in a network such as the internet which does not guarantee the communication quality, such a request is becoming stronger.
In order to perform the real-time communication, it is necessary to assure dedicated resources at the time of communication. As a resource reservation protocol in the internet, the resource reservation protocol (RSVP) is being examined by the internet engineering task force (IETF).
In a new network such as ATM, when a communication is started, resources for satisfying the communication quality adapted to the kind of communication are preliminarily assured by the signalling protocol Q.2931 and the communication is performed.
In the foregoing conventional techniques, it is necessary for a user terminal to issue a request for assuring the resource at the start time point of the communication. Even when the start time and end time of the communication are preliminarily known, the resources used during the communication cannot be preliminarily assured.
For example, with respect to a communication requiring a real-time performance such as a television conference whose holding time is preliminarily known, when the resource has been already assured by another communication at the start time point of the communication, a problem such that the sufficient quality of the communication cannot be guaranteed occurs.
Especially, in order to transmit multimedia data without interruption in an open network environment represented by the internet, it is necessary to assure the communication quality desired by the user in such a manner that switching nodes on a communication path assure resources necessary for the multimedia communication. As a technique for achieving the object, a communication protocol called a resource reservation protocol is examined in the above-mentioned internet engineering task force.
In the ATM (Asynchronous Transfer Mode) network, by designating the requested communication quality, band, and the like at the time of a setting of ATM switching devices as nodes in the network, the desired communication quality can be assured.
In the conventional techniques, the communication protocol for assuring the necessary network resources at the time of an actual communication is specified. Consequently, the network resource cannot be reversed until the start of the communication.
In order to reserve the network resource in the conventional techniques, a high degree of knowledge regarding the network resource is necessary. An end user of the network cannot easily reserve it.
Further, since the reservation state of the network resource cannot be known in the conventional techniques, it is difficult to try to reserve other resources by changing the conditions.
In the conventional techniques, further, there is not provided a method of permitting or rejecting a reservation by totally discriminating information such as the network use right of the user, priority of communication, and the like when it is determined whether the network resource can be reserved or not.
SUMMARY OF THE INVENTION
It is, therefore, a first fundamental object of the invention to enable a resource which will be used in a future communication to be reserved in order to solve the problems.
Among communications, there is a communication which does not always require a real-time performance such as a communication in which it is sufficient to transfer a file of a certain quantity until a certain time.
There is a case such that resources are already reserved by communications which do not require the real-time performance and a resource which is used for the communication requiring the real-time performance cannot be assured.
When the resource is used by the communication which does not require the real-time performance and the resource to be used for the communication requiring the real-time performance cannot be assured, it is a problem since the resource is not effectively used.
In order to solve the problem, it a second fundamental object of the invention is to enable the resource to be effectively used in addition to the first object.
It can be realized by, for example, reserving a resource used for a communication which does not require the real-time performance at an arbitrary time when the activity ratio of resources is low.
According to the invention, in order to achieve the first object, there is provided as a first mode a network connecting a plurality of switching nodes to which a plurality of user terminals are linked.
Each of the plurality of user terminals has a reservation requesting unit for sending a resource reservation request in which time information indicative of time to perform a communication is designated to a switching node to which the self user terminal is linked.
Each of the plurality of switching nodes includes:
a managing unit for managing a reservation state of each of resources which can be used by the self switching node among resources of the network together with time information indicative of time when a communication using the resource is performed, and
a reserving unit for obtaining a resource which is not reserved at a time indicated by the time information when the resource reservation request in which the time information is designated is received and for reserving the obtained resource as a resource to be used for the communication performed at the time shown by the time information.
According to the first mode, when the user designates a time to execute a communication in addition to the information such as the communication quality which is conventionally designated, the network reserves an unreserved resource at the designated time, so that the resource which will be used in a future communication can be reserved.
According to the first mode, the reservation requesting unit further designates priority information indicative of reservation priority of the relevant communication in the resource reservation request.
The managing unit further manages the priority information indicative of the reservation priority of the communication using the resource with respect to each of the resources which can be used by the self switching node among the resources of the network.
The reserving unit invalidates any reservation of a resource used for a communication having the reservation priority lower than the reservation priority shown by the priority information among the resources reserved at the time shown by the time information and reserves the resource whose reservation is invalidated as a resource to be used for the communication performed at the time shown by the time information when the resource reservation request in which the time information and the priority information is designated is received and there is no unreserved resource at the time indicated by the time information.
Consequently, even when necessary resources are short, by invalidating the reservation of the resource used for a communication having lower reservation priority, the network can preferentially reserve the resource used for a communication having higher reservation priority.
According to the invention, in order to achieve the second object, there is provided as a second mode a network connecting a plurality of switching modes to which a plurality of user terminals are linked.
Each of the plurality of user terminals has a reservation requesting unit for sending a resource reservation request in which permissi
Ikeda Naoya
Ishizaki Takeshi
Ohno Shuji
Ohta Masataka
Takihiro Masatoshi
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Sam Phirin
Ton Dang
LandOfFree
Network and switching node in which resource can be reserved does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Network and switching node in which resource can be reserved, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Network and switching node in which resource can be reserved will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2550919