Nortel Networks Nortel Networks This informational draft presents results of a study on using different drop precedence assignments to address fairness issues when UDP and TCP traffic share the same Assured Forwarding (AF) PHB class. In particular, six different possible combinations of drop precedence assignment were explored with two different models of RED parameter settings. We present results showing that the type of RED model utilized can play a role in the nature of bandwidth sharing between TCP and UDP flows. The results also show that with the current four Class, three Drop Precedence AF specification, complete fairness between TCP and UDP cannot be completely achieved using separate drop precedence assignment. This is true for both under-provisioned networks and over-provisioned networks. Certain drop precedence mapping schemes are beneficial to TCP while others are beneficial for UDP.