What is an encapsulator/decapsulator?
An encapsulator is a circuit that takes frames from an Ethernet LAN and prepares them for transport across a WAN network. A decapsulator performs the opposite function by accepting a stream of encapsulated frames from a WAN and preparing the frames for transmission on an Ethernet LAN. In the DS33X162 product family, the encapsulator/decapsulator also performs a variety of packet-processing functions such as inserting/removing information and prioritizing traffic. An encapsulator/decapsulator pair must sit at each end of a WAN connection. Using the virtual concatenation (VCAT) protocol, an encapsulator’s data can be spread over multiple physical PDH links to improve throughput and reduce latency. The VCAT term for the bundle of links used for this purpose is a virtually concatenated group (VCG). Each encapsulator supports one VCG.
