During the years between 1995 and 2000, there had been a strong competition between IP and ATM. MPLS that was approved by IETF in 1997, seems to end this competition with combination of best features of IP and ATM. MPLmS that is the equivalent of MPLS in optical networks, was designed in 1999. Afterwards, a new version of MPLmS, that is to say GMPLS, was developed in 2000 by IETF. Routing and signalling protocols that are supported by MPLS were extended to support GMPLS. The broadband boom, specifically growing data demand in high speed, and increasing bandwidth requirements has caused the evolution of the current transport networks. As a consequence, the IP over WDM networks, that integrate the traditional WDM networks having bandwidths of terabits and IP networks on which all applications run, has been developed. This article contains information on the MPLS, MPLmS and GMPLS network architectures which started to work on network backbones as a result of the evolution of telecommunications networks and new generation IP over WDM networks. © IEEE.