Multicast service is an important part of any modern routing architecture. Motivations for many-to-many multicast include general unpredictability of membership in many real applications; simplicity of the rendezvous for the application programmer; and low cost to end systems and switches in terms of state to maintain for the delivery tree. Shared trees have an even greater advantage over source based trees in the latter respect. Shared trees (as in the CBT model for Internet) are supported in the form of a single logical VC per multicast group (i.e., multipoint-to-multipoint VC or mp-mp VC) in the ATM networks. Recently CRAM, SEAM and SPAM have been proposed for supporting mp-mp VC. The work in this paper does a performance comparison of these three schemes, with respect to buffer requirements, end-to-end delay, packet jitter and traffic overhead. Our evaluation is carried out through extensive simulations with different topologies and sender traffic types