Path weighted equal-cost multipath

摘要

Routers balance network traffic among multiple paths through a network according to an amount of bandwidth that can be sent on an outgoing interface computed for each of the paths. For example, a router receives a link bandwidth for network links that are positioned between the first router and a second router of the network, and selects a plurality of forwarding paths from the first router to the second router. Upon determining that one of the network links is shared by multiple of the plurality of forwarding paths, the router computes a path bandwidth for each of the plurality of forwarding paths so as to account for splitting of link bandwidth of the shared network link across the multiple forwarding paths that share the network link. The router assigns packet flows to the forwarding paths based at least on the computed amount of bandwidth for each of the forwarding paths.

主权项

1. A method comprising:
receiving, with a first router of a network, a link bandwidth for each of one or more network links of the network that are positioned between the first router and a second router of the network; selecting, with the first router, a plurality of forwarding paths from the first router to the second router that each satisfy a constraint; determining that one of the network links is a common network link shared by multiple forwarding paths of the plurality of forwarding paths and positioned between the second router and a downstream router that is positioned between the first router and the second router along at least one of the forwarding paths; computing, by the first router, an amount of bandwidth that can be sent on an outgoing interface of the first router to a neighbor node on the multiple forwarding paths that share the common network link, wherein computing the amount of bandwidth comprises (i) accounting for splitting of the link bandwidth of the common network link across the multiple forwarding paths that share the common network link, and (ii) when the first router determines that the downstream router is not configured to account for splitting of the link bandwidth for the common network link across the multiple forwarding paths that share the common network link when the downstream router computes an amount of bandwidth that can be sent on an outgoing interface of the downstream router, computing the bandwidth based on a capability of the downstream router in load balancing received traffic across multiple next hops of the downstream router; selectively assigning, with the first router, packet flows to each of a plurality of outgoing interfaces of the first router based at least on the computed amount of bandwidth; receiving packets for the packet flows with the first router; and forwarding packets of each of the packets flows to the respective one of the plurality of outgoing interfaces to which the packet flow is assigned.