On the extension of ABR flow control to legacy LANs

In the current ATM LAN emulation (LANE) standard the issues of flow control and bandwidth allocation in the access units have not been adequately addressed. This paper investigates ways to enhance the functionality of typical legacy LAN-ATM access units (AUs) with the addition of low-level flow control mechanisms. The scheme proposed is based on the available bit rate (ABR) control mechanism currently standardized for ATM. Backpressure flow control is not terminated in the AU but is further extended to reach the nonATM legacy LAN stations. This is achieved by using a subset of the logical link control (LLC) protocol functionality executed between the AU and the legacy LAN stations. Apart from the QoS guarantees, the proposed method is transparent to the upper transport layer protocols and as such it does not require fundamental modifications to existing AUs and LAN stations