Random Packet Marking for Differentiated Services

Abstract

RPM is a packet marking scheme designed to perform marking on the aggregate traffic belonging to a single Assured Forwarding class at the DS domain ingress node. Decision about drop precedence for each packet is based on the comparison between the arrival rate and two prescribed rates, committed information rate (CIR) and peak information rate (PIR), which are specified in the customer-ISP contract. Colors representing drop precedence are assigned randomly with the probability, which is a function of the arrival rate, CIR and PIR. RPM does not require maintaining any per-flow state. The percentage of packets marked as green, yellow and red for each flow is roughly proportional to the flow's share of bandwidth. Marking probability function can also be modified to allow different degree of conformance to the contract.