Multi-domain routing and path computation is a well-known problem, which has extensively been analyzed in pure IP (packet) networks. In circuit switched optical multi-domain networks there are however still routing and path computation limitations that require additional investigations. Traffic grooming is combining a number of low speed traffic streams so that the high capacity of each lightpath may be used as efficiently as possible. As path computation implements the core of the grooming function, it is obvious that traffic grooming in optical multi-domain networks still needs additional research and development. This work presents a detailed IP/MPLS based ASON/GMPLS multi-domain framework to address the problems of lightpath routing and traffic grooming in optical multi-domain multi-layer networks.