Avoiding micro-loops in a ring topology of a network

摘要

In one embodiment, micro-loops are avoided in ring topologies of packet switching devices by changing the order of propagation of link state information concerning failed communications between a particular packet switching device and a neighbor packet switching device. In one embodiment, the particular packet switching device communicates link state information of a high cost of the particular communications (e.g., in the direction from particular to neighbor packet switching devices) such that this link state information will propagate towards the particular packet switching device from at least from the furthest packet switching device in the ring topology that is currently configured to forward packets having a destination address of the neighbor packet switching device through the particular packet switching device.

主权项

1. A network, comprising:
a plurality of packet switching devices communicatively coupled in a ring topology, with the plurality of packet switching devices including: a particular packet switching device, a first neighbor packet switching device, a second neighbor packet switching device, and an intermediate packet switching device; wherein the particular packet switching device is coupled as a neighbor to the first neighbor in the ring topology over particular communications such that the particular packet switching device and the first neighbor packet switching device are neighbors in the ring topology when said particular communications is available between the particular packet switching device and the first neighbor packet switching device; wherein the particular packet switching device and the second neighbor packet switching device are neighbors in the ring topology over different communications; wherein each of the plurality of packet switching devices are configured to exchange link state information with their current neighbors in the ring topology and to update their respective local forwarding information accordingly; and wherein the particular packet switching device is configured to cause a particular link state packet, including particular link state information identifying a very high cost of said particular communications for reaching the first neighbor packet switching device from the particular packet switching device, to be communicated to the first neighbor packet switching device through the ring topology such that said particular link state information is processed by the first neighbor packet switching device before any other packet switching device in the plurality of packet switching devices with corresponding particular link state information subsequently being propagated around the ring topology towards the particular packet switching device; and wherein the particular packet switching device is configured at least immediately not to flood said particular link state information to the second neighbor packet switching device to provide time for said propagating around the ring topology to occur first.