Abstract
Pre-congestion notification (PCN) in IP networks uses packet metering and marking within
a PCN domain to notify its egress nodes whether link-specific admissible or supportable
rate thresholds have been exceeded by high priority traffic. Based on this information simple
admission control and flow termination is implemented. The latter is a new flow control
function and useful in case of overload through high priority traffic which can occur
in spite of admission control, e.g., when traffic is rerouted in failure cases. Resilient admission
control admits only so much traffic that admitted traffic can be rerouted without
causing congestion on backup paths in case of a likely failures, e.g., single link failures.
We propose algorithms to configure the link-specific PCN rate thresholds such that resources
are utilized efficiently and fairly by competing traffic aggregates while meeting resilience
constraints. This is done for the single and dual marking PCN architecture whereby
the single marking case is more demanding since it requires that the supportable rate is a
fixed multiple of the admissible rate on all links within a single PCN domain. Furthermore,
we derive objective functions to optimize the underlying routing system for both cases. Our
performance results for various network types show that the dual marking PCN architecture
leads to significantly better resource efficiency than the single marking PCN architecture.
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