Technique for maintaining and enforcing relative policies with thresholds

摘要

A technique dynamically maintains and enforces relative policies for a prefix in a computer network. According to the novel technique, a node (e.g., an optimized edge router, OER) monitors performance characteristics for a particular prefix policy over a current path, and maintains a long-term average (LTA) value and a short-term average (STA) value of the performance characteristic. In the event the STA is worse than the LTA by a configurable amount, the prefix is considered “out-of-policy” (OOP) for that policy, and a new path may be selected accordingly. Otherwise, the prefix is considered “in-policy,” and the current path is upheld. Notably, a threshold may be manually configured to account for slow performance deterioration or “spikes,” such that if the performance characteristic (or STA) surpasses the threshold, the prefix is considered OOP.

主权项

1. A method for dynamically maintaining and enforcing relative policies for a prefix in a computer network, the method comprising:
monitoring, by a node of the computer network, a performance characteristic for a prefix over a current path, the prefix associated with a policy; maintaining a long-term average (LTA) value of the performance characteristic; maintaining a short-term average (STA) value of the performance characteristic; comparing the LTA value to the STA value to determine if the STA value indicates a worse value than the LTA value by at least a configurable amount; in the event the STA value indicates a worse value than the LTA value by at least the configurable amount, considering, by the node, the prefix to be out-of-policy (OOP) for the policy, wherein a prefix is a portion common to a plurality of addresses that is used by a routing protocol to render routing decisions; in the event the prefix is considered to be OOP, determining whether a more optimal path exists than the current path; and selecting the more optimal path as a new current path.