A recent seminal result of R?acke is that for any network there is an oblivious routing algorithm with a polylog competitive ratio with respect to congestion. Unfortunately, R?acke's construction is not polynomial time. We give a polynomial time construction that guarantee's R?acke's bounds, and more generally gives the true optimal ratio for any network. Categories and Subject Descriptors C.2.2 [Computer-Communication Networks]: Network Protocols--Routing protocols F.2.0 [Analysis of Algorithms and Problem Complexity]: General General Terms Algorithms Keywords Oblivious routing, Ellipsoid algorithm