This topic describes the background and functions of LCAS, and the advantages of LCAS to networks.

With the diverse and complex development of the services transmitted in the SDH network, the demands for various access bandwidths have increased. As a result, the earlier monotone bandwidths (such as a VC-4) do not meet the requirement. This has led to the emergence of the concatenation technology. Concatenation is classified into adjacent concatenation and virtual concatenation. The virtual concatenation is more flexible than the adjacent concatenation. The virtual concatenation also has a higher bandwidth utilization. The problems in both the adjacent concatenation and virtual concatenation are as follows:

• When any physical channel fails, all the concatenated channels fail and all the services are interrupted.
• After services are set up, if you adjust the bandwidth of the services, the services are affected to a great extent.

The link capacity adjustment scheme (LCAS) technology provides a solution to the preceding problems. LCAS improves and complements the virtual concatenation technology. LCAS dynamically adjusts the number of virtual containers required for service mapping to meet the bandwidth requirements of various services. Through LCAS, the bandwidth utilization increases and the robustness of virtual concatenation is enhanced.