Related Terms and Concepts

DTE, DCE, DSE, Multiplexing techniques - FDM, TDM, STDM, ATDM, DWDM;  Circuit-Switching, Packet-Switching, Cell-Switching, Datagram versus Virtual Circuit operation, SVC, PVC, Connection Orientation versus Connectionless operation, Logical Addresses, Physical Addresses, Logical Channel ID’s, LCGN/LCN, DLCI, VPI/VCI, single-mode and multi-mode fibre; The history, uses and relative merits of X.25, Frame-Relay and ATM.

X.25 Protocol

X.25 usage; Interface protocols versus Peer protocols, X.25 CO operation, X.25 usage, X.25 v OSI, Error Recovery, X.25 physical interface - X21 & X.21bis, HDLC-LAPB operation, LAP-B frame types, X.25 header fields, X.25 PVC’s and SVC’s, X.25 Call Setup, HDLC and X.25 flow-control processes, Fast-Select facility, Closed User Groups, PADS, X.3, Profiles, X.28, X.29