US 8,009,568 B2 · Congestion control in stateless domains

Abstract

Reducing congestion in an IP domain wherein congested data flows arriving at an egress edge node of the network are identified. Total congestion represented by the congested flows is determined, and a congestion extent notification is sent from the egress edge node to its ingress edge node peer. The congestion extent notification includes information regarding the total congestion and is sent on a per-class basis. Congested core routers in the network insert DSCPs into data packets passing through them to enable the egress edge nodes to identify the affected flows. The core routers may also send congestion metric messages, designed to follow the same path as the marked packets, to inform the egress edge nodes of the extent of congestion. In an alternative method, the egress edge nodes inform their ingress peers that congestion is present, without initially identifying the extent. The ingress edge node sends a query downstream with a congestion metric.

Claims16

Dependent claims

A method of reducing congestion in an IP network, comprising:

detecting congestion in a core router in the IP network;
determining a congestion metric for the core router, the congestion metric identifying the extent to which the transmission capacity for the core router is exceeded;
and
transmitting a congestion metric message from the core router, the congestion metric message including the congestion metric, to a downstream core router, wherein
if the downstream core router receiving the congestion metric message suffers less congestion than indicated by the congestion metric, forwarding the message unchanged and
if the downstream core router receiving the congestion metric message has higher congestion than the congestion metric, the downstream core router replaces the congestion metric with the downstream core router's own congestion metric.

3 more elements

Dependencies are inferred from the claim text.

Congestion control in stateless domains

Life of this patent

Congestion control in stateless domains

Life of this patent

Abstract

Claims16