Patent ID: 9654372
Date: 2017-05-16
CPC Classifications: H04L

Claim:
1. In a software defined network having switches including a first switch, a last switch, and intermediate switches there between, a default routing path existing between the first switch and the last switch, a system for computing path latency of the default routing path, the system comprising: a rule generator for inserting at least one respective flow monitoring rule in each of the switches, mandating for each of the switches, forwarding a received rule matching packet to a next switch on the path, and further mandating for the first switch and the last switch, sending a PacketIn message to a controller connected to the software defined network; a probe generator for inserting, in each of the switches, at least one respective flow monitoring probe matching the at least one respective flow monitoring rule in a same one the switches to initiate mandates specified by the at least one respective flow monitoring rule in the same one of the switches responsive to an arrival of the received rule matching packet thereat; a traffic listener for time-stamping the PacketIn messages to generate PacketIn timestamps; and a latency estimator for aggregating the PacketIn timestamps to obtain an aggregation of PacketIn timestamps, and estimating the path latency from the aggregation of PacketIn timestamps; wherein the latency estimator sends EchoRequest OpenFlow messages from the controller, measures respective return times of the EchoRequest OpenFlow messages, and adjusts the estimated path latency responsive to different control channel latencies determined from the respective measured return times, the controller being connected to at least some of the switches.