Dynamic admission control for IP networks

• US 6,738,819 B1
• Filed: 12/27/1999
• Issued: 05/18/2004
• Est. Priority Date: 12/27/1999
• Status: Expired due to Fees

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Yan, James, Aboul-Magd, Osama O., Li, Mingxing
• Primary Examiner(s): Wiley, David
• Assistant Examiner(s): Avellino, Joseph E
• Application Number:
  US09/472,151
• Time in Patent Office: 1,604 Days
• Field of Search: 709/232, 709/235, 709/223, 709/224, 370/256, 370/395.1, 370/395.21, 370/395.43, 370/360
• US Class Current: 709/229
• CPC Class Codes: H04L 45/302 Route determination based on requested QoS
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/781 Centralised allocation of resources
• CPC Class Codes: H04L 47/822 Collecting or measuring resource availability data
• CPC Class Codes: H04L 47/826 Involving periods of time
• CPC Class Codes: H04L 47/83 based on usage prediction

Abstract

A dynamic admission control(AC) mechanism for accepting traffic service requests to a carrier IP network based on an iterative measurement method, is disclosed. For each service offered, a network planner assigns a certain amount of resources. A QoS manager keeps track of the amount of unused resources for each particular service. The amount of unused resources are estimated using actual measurements of load levels on various links of the network. Each router monitors the loading level on each of its outgoing interfaces. Those measurements are then transferred to the QoS manager upon request, or periodically at time intervals “T”.

Claims

1. A method of controlling admission of a service request in an IP network with differentiated services capabilities, said IP network including a plurality of links for communication path:

comprising the steps of;

at a network element,

(a) periodically measuring traffic load on each link in said IP network for each service offered by said network;

at a QoS manager,

(b) administering a single available resource value for each service;

(c) comparing said available resource value for a service requested with a resource determined by a parameter for said request when receiving said request; and

(d) determining, in response to the comparison, whether the amount of traffic of said service requested is allowed to enter said network and accepting said requests, said administering step (b) including;

periodically determining said available resource value based on the measurement on each link for said service, and

dynamically adjusting said available resource value for said service requested based on said parameter to account for the utilization of said IP network by said service.

2. The method of claim 1, wherein said parameter includes a required bandwidth.

3. The method of claim 2, wherein said step of determining said available resource value comprises the step of periodically determining, based on said measurement, a single admit limit (AL) for each service offered by said network, said step of accepting said request comprises the step of accepting said request if said AL for said service requested is not exceeded by the resource, and said step of adjusting said available resource value comprises the step of decreasing said AL for said service requested based on the accepted parameter.

4. The method of claim 3, wherein said step of administering a single available resource value comprises the step of initializing said admit limit (AL) by a predetermined bandwidth utilization capacity allocated to said service offered on the weakest link of said network.

5. The method of claim 4, wherein said step of administering a single available resource value comprises the step of initializing said AL by the smallest remaining capacity on all links for said offered service.

6. The method of claim 4, further comprising accepting said request whenever said required bandwidth does not exceed said AL for said service requested, and rejecting said request whenever said required bandwidth exceeds said AL for said service requested.

7. The method of claim 6, wherein said step of adjusting said available resource value comprising maintaining said AL If said request is rejected, and dynamically adjusting said AL by the amount of said required bandwidth after accepting said request.

8. The method of claim 6, wherein said step of adjusting said available resource value comprises the step of resetting, based on said measurement, said AL to the remaining capacity of the new weakest link of said network.

9. The method of claim 3, wherein said step of periodically measuring is performed off line.

10. The method of claim 3, wherein said step of periodically measuring is performed by each router.

11. The method of claim 3, wherein said step of periodically measuring is performed after a preset time interval.

12. The method of claim 3, wherein said step of periodically measuring is performed each time said admit limit becomes smaller than a preset value.

13. The method of claim 1, wherein said parameter includes a type of the service.

14. The method of claim 1, wherein said parameter includes a destination.

15. The method of claim 1, comprising the following steps performed by an edge router:

intercepting said request by said edge router;

determining if said request is single-ended or double-ended;

identifying an assigned path if said request is double-ended; and

forwarding the parameter including said assigned path to a QoS manager, at said QoS manager, performing said step of adjusting said available resource value for each link forming said assigned path of said double-ended request, and for each link in said network for said single-ended request.

16. The method of claim 15, wherein said step of identifying an assigned path includes creating and maintaining a spanning tree at said edge router.

17. The method of claim 15, wherein said assigned path comprising a list of link identifications.

18. The method of claim 15, wherein said assigned path comprising a list of router interface identifications.

19. The method of claim 15, wherein said traffic load on each link in said network is reduced by a weighted amount each time said double ended request terminates.

20. The method of claim 19, wherein said step of identifying an assigned path includes creating and maintaining an edge-to-edge routing table at said QoS manager.

21. The method of claim 1, further comprising the following steps:

determining if said request is single-ended or double-ended;

maintaining the current network topology and link state information; and

identifying an assigned path if said request is double-ended, at said QoS manager, performing said step of adjusting said available resource value for each link forming said assigned path of said double-ended request, and for each link in said network for said single-ended request.

22. A QoS manager for admission control (AC) of a traffic service request in an IP network with differentiated services capabilities, comprising:

an update engine block for periodically providing a single admit limit (AL) to each service for a parameter of interest of said request based on a measurements performed on each link of said network for said service;

an admit limit block for periodically requesting updates of said AL and recording same;

an admission control (AC) block for receiving said request, determining whether the amount of traffic of said service for said request is allowed to enter said network by comparing said AL for said service requested with said parameter and for dynamically adjusting said AL for said service requested based on the accepted parameter.

23. The QoS manager of claim 22, wherein said measurements are performed at a preset time interval.

24. A router for admission control (AC) of a traffic service request in an IP network with differentiated services capabilities, comprising:

I/O interface (IF) means for establishing a direct link with a single or more other routers of said network;

means for monitoring said I/O (IF) means and measuring available resources in said network corresponding to a parameter of interest of said request, and for transmitting same to a QoS manager,

whereby said QoS manager administers a single available resource value for each service, which is periodically determined by said measurement on each link for said service, and said QoS manager determines whether the amount of traffic of said service for said request is allowed to enter said network by comparing said parameter with said available resources value for said service requested, accepts the traffic for said request, and dynamically adjusts said available resource value for said service requested based on the accepted parameter.

25. The router of claim 24, wherein said parameter is measured at a preset time interval.