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> Advanti sAbstrac t This report concentrates on specific requirements an d goals of the research networks supported by ANSNET , but applies to any TCP dominated high speed WA N and in particular those striving to support high spee d end-to-end flows . Measurements have been made unde r conditions intended to better understand performanc e barriers imposed by network equipment queueing capacities and queue drop strategies .The IBM RS/6000 based routers currently supportin g ANSNET performed very well in these tests . Measurements have been made with the current software an d performance enhanced software . Single TCP flows are able to achieve 40 Mb/s and competing multiple TC P flows achieve over 41 Mb/s link utilization on 44 .7 Mb/ s DS3 links with delays comparable to US cross continen t ANSNET delays . Congestion collapse is demonstrate d with intentionally reduced queueing capacity and usin g window sizes much larger than optimal .A variation of Floyd and Jacobson's Random Earl y Detection (RED) algorithm [1] is tested . Performanc e improved with the use of RED for tests involving multiple flows . With RED and queueing capacity at o r above the delay bandwidth product, congestion collaps e is avoided, allowing the maximum window size to safel y be set arbitrarily high .Queueing capacity greater than or equal to the dela y bandwidth product and RED are recommended . RED provides performance improvement in all but the singl e flow case, but cannot substitute for adequate queuein g capacity, particularly if high speed flows are to be supported .

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