Detection of asymmetric network routes

摘要

Route asymmetry is detected in a network by running a route tracing program to trace routes between a first element of the network and a second element of the network. The route tracing program need be run at only a single network element, such as the first network element. Forward and reverse routes between the first and second network elements are identified as asymmetric if performance data from the route tracing program indicates a significant deviation from an expected monotonic characteristic as a function of time-to-live values of respective packets transmitted by the route tracing program.

主权项

1. A method comprising:
executing a route tracing program, at a first network element, the route tracing program transmitting a sequence of packets with different time-to-live values along a forward route that spans from the first network element to a second network element, wherein the route tracing program specifies the second network element as the destination of the sequence of packets, wherein a reverse route spans from the second network element to the first network element, and wherein the sequence of packets are configured to trigger control messages to be transmitted to the first network element; in response to executing the route tracing program, calculating performance measurements based on the control messages corresponding to the different time-to-live values, and wherein a first portion of the control messages has been transmitted to the first network element via the forward route and a second portion of the control messages has been transmitted to the first network element via the reverse route; determining an expected monotonic characteristic that is exhibited by the performance measurements in relation to the different time-to-live values; and identifying the forward route and the reverse route as being asymmetric with each other when a performance measurement that corresponds to an individual time-to-live value indicates a deviation, over a predetermined deviation threshold, from the expected monotonic characteristic.