Multiplex communications – Data flow congestion prevention or control – Flow control of data transmission through a network
Reexamination Certificate
1999-11-01
2004-07-20
Pham, Chi (Department: 2663)
Multiplex communications
Data flow congestion prevention or control
Flow control of data transmission through a network
C370S355000
Reexamination Certificate
active
06765872
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a routing apparatus and a routing method, in particular, to a routing apparatus and a routing method suitable for use when it is necessary to reserve a resource (for example, a resource relating to a communication such as a bandwidth and the like) at the time of communication in a communication network performing TCP/IP (Transmission Control Protocol/Internet Protocol) communication.
(2) Description of the Related Art
In order to furnish services strict with delay [for example, VOD (Video On Demand), voice service and the like] using IP over the Internet, it is necessary to secure a resource (bandwidth, mainly) for the communication service. To cope with it, there is a protocol for reserving a resource called RSVP (Resource Reservation Protocol) defined by IETF (Internet Engineering Task Force).
RSVP is a technique for securing a predetermined necessary bandwidth for a session (connection) established between a sender and a receiver of data (packet) in TCP/IP layer and assign it [guaranteeing predetermined QoS (Quality of Service)]. However, RSVP itself does not have a routing protocol. For this, an existing protocol is used in a routing (destination determining) process on data by a routing apparatus [namely, a so-called IP router or an ATM (Asynchronous Transfer Mode) switch or the like having a function equivalent to that of the IP router].
Namely, in terms of packet data for RSVP such as an RSVP message (request for securing a resource) or the like, the existing routing apparatus (routing method) determines the next packet transfer target (adjacent routing apparatus; route) on the basis of only an IP address given to the packet data, and performs a packet transferring process, like other ordinary packet data.
Since such the known routing apparatus (routing method) performs a routing on the basis of only an IP address, there is possibility of trying a routing for an RSVP message to an apparatus in which a bandwidth cannot be secured (or is hardly secured). A reason of this is that the present IP is designed for a dynamic, best effort apparatus (a network configured on the basis of a theory that guarantees a necessary bandwidth for a communication when there is a margin in the bandwidth, but does not guarantee when there is not a margin), and does not possess a function of considering a state of use of a resource (for example, an idle bandwidth in the case of bandwidth) in another apparatus that can be the next packet transfer target (adjacent routing apparatus).
For this, there is a possibility of frequently performing a routing to an apparatus in which a bandwidth requested by an RSVP message cannot be secured (or is hardly secured) in the above routing apparatus. In consequence, a resource (a rate of use of CPU or the like) in the network is wastefully consumed so that loss might be generated. As a result, there is a possibility of degrading serviceability such that a service (VOD service or the like) requested by the user cannot be provided.
SUMMARY OF THE INVENTION
In the light of the above problems, an object of the present invention is to provide a routing apparatus and a routing method, in which a routing process is performed in consideration of a state of use of a resource in the adjacent routing apparatus when a request for reserving a resource (communication resource) is received, whereby a wasteful routing is prevented at the time of resource reservation.
The present invention therefore provides a routing apparatus comprising a routing controlling unit for controlling transfer of a received packet data to an adjacent routing apparatus on a basis of destination information of the packet data, a first resource management unit for managing resource management information regarding communication resource in another routing apparatus that can be the adjacent routing apparatus, and a first determining unit for securing a communication resource upon receiving a packet data for a reservation request, and determining the adjacent routing apparatus on the basis of destination information given to the packet data and the resource management information.
The above first resource management unit may hold at least information in which routing information on another routing apparatus that can be the adjacent routing apparatus and use state information on the communication resource in the same are corresponded to each other as the resource management information. In such case, it is desirable that the above first determining unit is configured as a routing determining unit for reservation request for determining routing information for another routing apparatus in which a communication resource according to the packet data for a reservation request can be secured as routing information for the adjacent routing apparatus on the basis of the use state information, and the routing controlling unit controls the routing on the basis of the routing information determined by the reservation request routing determining unit.
The present invention also provides a routing method used in a communication network in which a plurality of routing apparatuses each handling packet data for a desired communication service comprising the steps of receiving a packet data for a communication resource reservation request; and carrying out a routing process for transferring the reservation request to a adjacent routing apparatus in consideration of at least a state of use of a communication resource in another routing apparatus that can be the adjacent routing apparatus.
According to the routing apparatus and the routing method of this invention, it is possible to perform a routing in consideration of at least a state of use of a communication resource in another routing apparatus that can be the adjacent routing apparatus when a reservation request for reserving use of a communication resource required to implement a desired communication service is received. It is therefore possible to largely decrease a possibility of performing a wasteful routing process to a routing apparatus in which a communication resource according to the above reservation request cannot be secured or is hardly secured, so that the communication resource is effectively used.
The above routing controlling unit may include a first resource management information creating/updating unit for creating or updating the resource management information on the basis of a record of securing a communication resource in another routing apparatus that was once the adjacent routing apparatus for past packet data for a reservation request.
It is thereby possible to automatically hold information on a recent state of use of a communication resource in another routing apparatus, thus easily grasp the recent state of use of a communication resource in the same.
The first resource management information creating/updating unit may comprise a first timer unit for measuring a first predetermined period from when the resource management information is created, a first information confirming unit for confirming whether or not resource management information held longer than the predetermined period exists in the first resource management unit on the basis of time-measuring information of the first timer unit, and a first information deleting unit for deleting resource management information in the first resource management unit when the first information confirming unit confirms that the resource management information held longer than the first predetermined period exists in the first resource management unit.
As above, the created resource management information is held for a predetermined period. When a similar reservation request is received within the predetermined period, a routing for the reservation request is performed on the basis of the created resource management information, so that a load of the routing is decreased, and a memory quantity required to hold information is decreased.
The above first resource management info
Ferris Derrick W
Fujitsu Limited
Muchin Katten
Pham Chi
Rosenman Zavis
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