Method and apparatus for transporting packets with specific traffic flows having strict packet ordering requirements over a network using multipath techniques

Abstract

The method that is disclosed enables specific information network traffic flows to retain packet ordering in a packet network in which multipath techniques are used. In a common network usage a plurality of traffic flows may be aggregated into a larger traffic flow. In such a situation, a finest granularity of individual traffic flow is referred to as a microflow and an aggregation of traffic flows is referred to as a traffic aggregate. The traffic aggregate may take a path from an ordered set of nodes including a first network element referred to as an ingress node through zero or more intermediate network elements referred to as midpoint nodes, to a final network known as the egress node. The ordered set of nodes traversed by such a traffic aggregate is referred to as the path taken by that traffic flow. At any node prior to the egress, the traffic aggregate may be split among multiple links or lower layer paths in reaching the next node in the path. In such a circumstance, the traffic aggregate is split among the available links or lower layer paths. Techniques for splitting traffic are collectively referred to as multipath techniques, or more briefly as multipath. Individual links or lower layer paths within a multipath are referred to as component links. Individual traffic flows may be identified by various existing multipath techniques. A set of existing multipath techniques are able to keep all packets within a given microflow on the same component link. The method disclosed allows specific traffic aggregates within a larger traffic aggregate to be carried on a single component link while allowing other traffic aggregates within the larger traffic aggregate to be spread among multiple component links.