Virtual concatenation is considered the primary enhancement to voice optimized SONET/SDH, in order to support the transport of variable bit data streams.
Other recent SONET/SDH enhancements include Link Capacity Adjustment Scheme (LCAS), and the Generic Framing Procedure (GFP).
Bandwidth is allocated in multiples of 51 Mbit/s and therefore high-order VCAT can be used to provision sub-rate traffic across Gigabit Ethernet.
Bandwidth is allocated in 2-Mbit/s chunks and therefore low-order VCAT can be used to provision sub-rate traffic across 10/100-Mbit/s Ethernet used in the access network.
The Virtual Concatenation protocol performs its content delivery through a process called byte-interleaving.
The major problem with differential delay is the requirement for high speed buffers at the receiving node to store incoming information while all paths converge.
Several heuristics based algorithms exist, that attempt to minimize the differential delay to provide a solution.