Review of the measurements of the strong coupling constant at LEP 2

Since 1995, LEP has steadily increased the center of mass energy of the colliding beams, from the M_Z resonance to 133, 161 and 172 GeV. New measurements of the strong coupling constant, alpha_s, at these energies have been performed by the LEP experiments, L3, ALEPH, OPAL and DELPHI. In this article, the new results are summarized, and combined with the previous LEP measurement of alpha_s(M_Z) in order to obtain an updated LEP average of alpha_s(M_Z) = 0.120 +- 0.005.