US 7,126,910 B1Granted

Load balancing technique for a resilient packet ring

AssigneeAlcatel

InventorKamakshi Sridhar

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Abstract

A technique for load balancing in resilient packet ring (“RPR”) networks, including wavelength division multiplex RPR (“WDMRPR”) networks is described. In one embodiment, the present technique comprises implementing on every node a QoS/BB monitor, which is common to all rings in the RPR and has knowledge of traffic performance for each class on each ring of the RPR, which information is obtained through periodic measurements or in response to failure events. This allows the monitor to vary the QoS parameters on a node, for a particular traffic class, to achieve load balancing. Likewise, the QoS/BB monitor can signal to the BB entity at higher layers to vary the BB parameters on a node for a particular class to achieve load balancing. The QoS/BB monitor enables QoS and BB parameter changes to be coordinated with one another.

Claims18

Dependent claims

A method of implementing load balancing in a resilient packet ring (“RPR”) network comprising a plurality of nodes and first and second rings each comprising a plurality of links for carrying information between the nodes in a clockwise direction and a counterclockwise direction, respectively, wherein adjacent ones of the nodes are connected by two of the links, the method comprising the steps of, for one of the nodes:

determining whether a load imbalance exists at the node in connection with a first class of service, using a technique selected from the group consisting of measuring and comparing delays experienced by a marked packet sent from the node to a second node via the first and second rings, respectively, and comparing a number of dropped packets on the first and second rings with a preselected maximum value;
and
responsive to a determination that a load imbalance exists:
changing Bandwidth Broker (“BB”) parameters at the node for the first class of service to cause new flows to be diverted from a more heavily loaded one of the rings to a less heavily loaded one of the rings;
and
changing Quality of Service (“QoS”) parameters at the node for the first class of service to improve traffic performance on the more heavily loaded one of the rings, while increasing bandwidth utilization on the less heavily loaded one of the rings.

3 more elements

Apparatus for implementing load balancing in a resilient packet ring (“RPR”) network comprising a plurality of nodes and first and second rings each comprising a plurality of links for carrying information between the nodes in a clockwise direction and a counterclockwise direction, respectively, wherein adjacent ones of the nodes are connected by two of the links, the apparatus comprising, at one of the nodes:

means for detecting at the node a load imbalance in connection with a first class of service, including means using a technique selected from the group consisting of measuring and comparing delays experienced by a marked packet sent from the node to a second node via the first and second rings, respectively, and comparing a number of dropped packets on the first and second rings with a preselected maximum value;
means responsive to detection at the node of a load imbalance for changing Bandwidth Broker (“BB”) parameters at the node for the first class of service to cause new flows to be diverted from a more heavily loaded one of the rings to a less heavily loaded one of the rings;
and
means responsive to detection at the node of a load imbalance for changing Quality of Service (“QoS”) parameters at the node for the first class of service to improve traffic performance on the more heavily loaded one of the rings, while increasing bandwidth utilization on the less heavily loaded one of the rings.

1 more element

Dependencies are inferred from the claim text.