Data link control emulation: rapid prototyping for high-speed networks

Data link control (DLC) emulation is an efficient and effective methodology for rapid-prototyping of high-speed network technologies. In a high-speed network attachment, DLC emulation replaces the original protocol stack with one that has two DLC protocols and performs all the necessary conversions between them. The lower portion of the protocol stack implements the prototyped network, while the upper portion implements the original high-speed network stack. This allows applications to take advantage of the improved characteristics of emerging network technologies without restructuring, rewriting, or making any investment in application, protocol, or system software that interfaces to the original high-speed network adapter. In this fashion, evaluation of new technologies is feasible in real environments at a low cost. We show that DLC emulation is a flexible and general technique that supports a wide range of data link control protocols, and we demonstrate its effectiveness through a case study, where an FDDI adapter is used to provide SMDS connectivity over T1 and T3 links. We show that DLC emulation achieves high performance at a significantly low development cost for an attachment to a new network technology, because frame conversion between DIC protocols can be implemented efficiently "on-the-fly" using rapid-prototyping hardware techniques.