Virtual concatenation (VCAT) is a standardized layer 1 inverse multiplexing technique that can be applied to the optical transport network (OTN), synchronous optical network (SONET), synchronous digital hierarchy (SDH), and plesiochronous digital hierarchy (PDH) component signals. By inverse multiplexing, it combines multiple links at a particular layer into aggregate links to achieve a commensurate increase in available bandwidth on the aggregate link. While any inverse multiplexing scheme is about "more bandwidth", the VCAT/LCAS is a general technique that can enable a fairly broad range of network features such as (1) right sizing bandwidth for data applications, (2) bandwidth extraction from a mesh network, (3), bandwidth on demand and IP traffic engineering, and (4) provides new forms of protection-restoration and graceful degradation. In this paper, the authors have given a quick overview of VCAT/LCAS technology and just a few examples of its applications