Apparatus and method for resource reservation in a network system

• US 6,453,349 B1
• Filed: 12/16/1998
• Issued: 09/17/2002
• Est. Priority Date: 07/14/1998
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kano, Shinya, Chugo, Akira
• Primary Examiner(s): Barot, Bharat
• Application Number:
  US09/212,636
• Time in Patent Office: 1,371 Days
• Field of Search: 704/200, 704/204-205, 704/217-219, 704/223-226, 704/238-242, 704/245-246, 370/351, 370/355-356, 370/389-390, 370/342, 370/395-397, 370/400-401, 370/409, 370/231-233
• US Class Current: 709/226
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/724 at intermediate nodes, e.g. resource reservation protocol [RSVP]
• CPC Class Codes: H04L 47/826 Involving periods of time

Abstract

A network system comprising terminals and relaying nodes having a reservation message processing unit for transferring a packet wherein a packet receiving terminal 3 requests a reservation of network resources. The packet receiving terminal 3 transmits to a packet transmitting terminal 1 a request message in which a reservation request condition is stored in order to request a resource reservation, the packet transmitting terminal 1 having received the request message transmits to the relaying node 2 on the same route as the packet an acknowledgement message in which the reservation request condition is stored. Each relaying node 2 provides a resource reservation for the home relaying node according to the reservation request condition in the acknowledgement message and transfers the acknowledgement message to the same route as the packet. After the acknowledgement message has passed through all the relaying node 2, and when the packet receiving terminal has received the acknowledgement message, a network resource reservation procedure is completed.

Claims

1. A network system comprising;

terminals and relaying nodes each having a reservation message processing unit for transferring a packet wherein;

the reservation message processing unit of a packet receiving terminal transmits to a packet transmitting terminal a request message in which a reservation request condition is stored in order to request a resource reservation for the packet;

the reservation message processing unit of the packet transmitting terminal having received the request message transmits to the relaying nodes on the same route as the packet an acknowledgement message in which the reservation request condition is stored responsive to the request message;

the reservation message processing unit of each relaying node provides a resource reservation for the relaying node itself according to the reservation request condition in the acknowledgement message instead of the request message and transfers the acknowledgement message to the same route as the packet; and

after the acknowledgement message has passed through all the relaying nodes which relay the packet and then the reservation message processing unit of the packet receiving terminal has received the acknowledgement message, a network resource reservation procedure is completed.

2. A network system as claimed in claim 1 wherein the acknowledgement message stores an address of the packet receiving terminal and a protocol identifier which specifies a protocol indicating a resource reservation procedure, the packet transmitting terminal and the relaying nodes respectively maintain in their reservation message processing units a routing table for transmitting the acknowledgement message to the same route as the packet, and the reservation message processing unit of each relaying node checks the protocol identifier to determine whether or not to receive the acknowledgement message.

3. A network system as claimed in claim 1 wherein the acknowledgement message stores an address of the packet receiving terminal and an address of a subsequent relaying node which is retrieved by using the address of the packet receiving terminal as a key from a routing table for transmitting the acknowledgement message to the same route as the packet, the packet transmitting terminal and the relaying nodes respectively maintains the routing table in their reservation message processing units, and the reservation message processing unit of each relaying node checks if the address in the acknowledgement message is a home address to determine whether or not to receive the acknowledgement message.

4. A network system as claimed in claim 1 wherein each relaying node has a reservation acceptance determining unit which determines whether or not to accept the reservation request condition in the acknowledgement message, and the reservation message processing unit transfers the acknowledgement message if the condition should be accepted, while transmitting an error message notifying an error to the packet receiving terminal if not.

5. A network system as claimed in claim 4 wherein the reservation message processing unit of the packet receiving terminal, having confirmed by receiving the error message that the reservation request has not been accepted, modifies the reservation request condition and resends the request reservation.

6. A network system as claimed in claim 1 wherein each relaying node has a reservation acceptance determining unit which determines whether or not to accept the reservation request condition in the acknowledgement message, and the reservation message processing unit transfers the acknowledgement message if the condition should be accepted, while providing the resource reservation with an allowable condition for each relaying node to accept the reservation and transfers the acknowledgement message which has the reservation request condition modified to the accepted condition if not.

7. A network system as claimed in claim 6 wherein a flag is provided in the acknowledgement message to indicate that the reservation request condition has been modified, the flag is set when the reservation message processing unit of each relaying node modifies the reservation request condition in the acknowledgement message, and by checking the flag the reservation message processing unit of the packet receiving terminal confirms whether or not the reservation request has been accepted by each relaying node.

8. A network system as claimed in claim 6 wherein the reservation message processing unit of the packet receiving terminal compares the requested reservation request condition with the reservation request condition stored in the acknowledgement message and confirms, depending on the compared result, whether or not the reservation request has been accepted by each relaying node.

9. A network system as claimed in claim 1 wherein in order to release the reserved resource within each relaying node, a reserved resource releasing message is sent in at least one of the following directions:

from the packet receiving terminal to the packet transmitting terminal;

from the packet transmitting terminal to the relaying nodes;

between the relaying nodes; and

from the relaying nodes to the packet receiving terminal.

10. A network system as claimed in claim 1 wherein in order to maintain the resource within each relaying node, a reservation keeping message is transmitted periodically in at least one of the following directions:

from the packet receiving terminal to the packet transmitting terminal;

from the packet transmitting terminal to the relaying nodes;

between the relaying nodes; and

from the relaying nodes to the packet receiving terminal, and if the resource reservation keeping message has not been received for more than a fixed period of time, the resource is released and the periodical transmission of the resource reservation keeping message is discontinued.

11. A network system as claimed in claim 1 wherein the reservation message processing unit of the packet transmitting terminal compares a resource specified in the reservation request condition within the received request message and a resource required by the packet to be reserved, and if the former is larger than the latter, transmits the acknowledgement message after the reservation request condition having been modified.

12. A network system as claimed in claim 11 wherein a flag is provided in the acknowledgement message to indicate that the reservation condition has been modified, the flag is set when the reservation message processing unit of the packet transmitting terminal modifies the reservation condition in the acknowledgement message, and by checking the flag the packet receiving terminal confirms whether or not the reservation request condition has been modified by the packet transmitting terminal to the resource required by the packet.

13. A network system as claimed in claim 1 wherein the reservation message processing units of the packet transmitting terminal and the relaying nodes preliminarily modify the reservation condition in the received message according to control information on resource reservation made by at least one of a network manager and a relaying node manager.

14. A network system as claimed in claim 1 wherein a flag is provided in the acknowledgement message in order for the packet receiving terminal to notify the completion of a reservation procedure to the packet transmitting terminal, the reservation message processing unit of the packet transmitting terminal sets the flag upon transmitting the acknowledgement message, and the reservation message processing unit of the packet receiving terminal which has received the acknowledgement message with the flag set notifies the completion of a reservation procedure to the packet transmitting terminal through a reservation completion notifying message.

15. A packet transmitting terminal handling packets which have stored therein reservation request conditions for resource reservation wherein;

the packet transmitting terminal which has received a request message which has stored therein the reservation request conditions for resource reservation requested by a packet receiving terminal performs routing an acknowledgement message which has stored therein the reservation request condition responsive to the request message to a relaying node, providing a resource reservation upon receiving the acknowledgement message, by a reservation message processing unit of the packet transmitting terminal.

16. A relaying node handling packets which have stored therein reservation request conditions wherein;

the relaying node which has received from a packet transmitting terminal an acknowledgement message which has stored therein the reservation request conditions for resource reservation requested by a packet receiving terminal provides a resource reservation for the relaying node itself according to the reservation request condition in the acknowledgement message and performs routing the acknowledgement message to another relaying node or to the packet receiving terminal by a reservation message processing unit of the relaying node.

17. A packet receiving terminal handling packets which have stored therein reservation request conditions wherein;

the packet receiving terminal which has received from a relaying node an acknowledgement message transmitted by a packet transmitting terminal which have stored therein the reservation request conditions requested by the packet receiving terminal and relayed by a relaying node, having provided a resource reservation upon receiving the acknowledgement message, completes a resource reservation procedure with the packet transmitting terminal.