TUNING ROUTING METRICS TO REDUCE MAXIMUM LINK UTILIZATION AND END-TO-END DELAY VIOLATIONS
A metric tuning technique optimizes the link utilization of a set of links in a network and end-to-end delay or latency constraints. In the embodiments, a delay constraint between node pairs in the network is determined and used in addition to the link utilization to optimize the network. An interactive user interface is provided to allow a user to specify limits and the delay constraints, and to select the sets of links to be addressed. The delay constraints may be specified on an end-to-end or per-link basis. In addition, the latency requirements may be specified for various types of traffic, such as voice, streaming, etc. In one embodiment, the link utilization is minimized within a node pair latency constraint. Link utilization constraints may be preferred before satisfying delay or latency constraints.
1 . A method for tuning routing metrics to satisfy compliance of performance of a network, wherein performance of the network is constrained by at least one end-to-end delay constraint, said method comprising:
determining a first plurality of metrics that are used by a routing protocol to select first routes for communication of messages among nodes of a network, each metric being associated with a corresponding cost of one or more of a plurality of links of the network;
determining a network performance measure based on first routes; and
modifying one or more select metrics of the first plurality of metrics to provide a second plurality of metrics that provides an improvement of the network performance measure based on second routes selected by the routing protocol based on the second plurality of metrics, wherein the modifying of the one or more select metrics is substantially limited to modifications that cause the routing protocol to comply with the end-to-end delay constraint.
2 . The method of claim 1 , wherein the network performance measure includes a measure of link utilization.
3 . The method of claim 2 , wherein the improvement includes a reduction in a maximum of link utilization among the plurality of links.
4 . The method of claim 1 , wherein modifying the one or more select metrics includes: selecting a candidate link having a link utilization that exceeds a link utilization threshold, determining a new value of the select metric corresponding to the candidate link to achieve a new route with a lower end-to-end delay, and setting the select metric to the new value.
5 . The method of claim 4 , including: identifying each of a set of metric values that provide a reduction of the link utilization for the candidate link, and determining the new value includes selecting from the set of metric values.
6 . The method of claim 5 , wherein each of the set of metric values corresponds to one of: a first metric value that causes the routing protocol to share a demand for the link with another link, and a second metric value that causes the routing protocol to select another link for routing the demand with a lower delay.
7 . The method of claim 1 , wherein the one or more select metrics correspond to one or more links that are randomly selected from a set of candidate links.
8 . The method of claim 1 , wherein the set of candidate links correspond to links having a high degree of utilization and satisfying a respective delay constraint.
9 . The method of claim 8 , wherein the links are randomly selected based on a probability of selection that is based on a degree of utilization and latency of each link.
10 . The method of claim 1 , wherein the one or more select metrics are selected based on a cost associated with reducing delay of the route by modifying the metric.
11 . A system for tuning route metrics to satisfy one or more delay constraints desired for a network comprising:
a configuration engine coupled to a network and configured to determine a first plurality of metrics that are used by a routing protocol to select first routes for communication of messages among nodes of a network, each metric being associated with a corresponding cost of one or more of a plurality of links of the network; and
a traffic engineering server configured to determine a network performance measure based on first routes and modify one or more select metrics of the first plurality of metrics to provide a second plurality of metrics that provides an improvement of the network performance measure based on second routes selected by the routing protocol based on the second plurality of metrics, wherein the modifications of the one or more select metrics is substantially limited to modifications that cause the routing protocol to comply with the end-to-end delay constraint.
12 . The system of claim 11 , wherein the configuration engine is configured to measure link utilization.
13 . The system of claim 11 , wherein the traffic engineering server is configured to select a candidate link having a link utilization that exceeds a link utilization threshold, determine a new value of the select metric corresponding to the candidate link to achieve a new route with a lower end-to-end delay, and set the select metric to the new value.
14 . The system of claim 13 , wherein the traffic engineering server is configured to identify each of a set of metric values that provide a reduction of the link utilization for the candidate link, and determine the new value based on a set of metric values.
15 . The system of claim 14 , wherein each of the set of metric values corresponds to one of: a first metric value that causes the routing protocol to share a demand for the link with another link, and a second metric value that causes the routing protocol to select another link for routing the demand with a lower delay.
16 . The system of claim 11 , wherein the traffic engineering server is configured to randomly select one link from a set of candidate links.
17 . The system of claim 11 , wherein the traffic engineering server is configured to select candidate links based on a degree of utilization and latency of each link.
18 . The system of claim 11 , wherein the traffic engineering server is configured to select links having a high degree of utilization and satisfying a respective delay constraint for candidate links.
19 . The system of claim 11 , wherein the traffic engineering server is configured to select one or more metrics based on a cost associated with reducing delay of the route by modifying the metric.