Support of the GFR transfer capability over a PON access system

In this contribution we focus on providing bandwidth guarantees for the guaranteed frame rate (GFR) transfer capability in the context of ATM-based passive optical networks (APONs). Our work builds on the research performed on ATM multiplexers and extends it with the specificities of the APON network. We study the performance of several known buffer management schemes (DFBA, WFBA, per-VC threshold), combined with either FIFO or per-VC scheduling, when applied on virtual circuits carrying TCP/IP traffic. We find that with fairly small buffers at the ONUs (optical network units), the schemes based on per-VC scheduling yield very good performance in a large number of cases. The schemes based on FIFO scheduling suffer from unfairness, although they do provide bandwidth guarantees in case the GFR bandwidth reservation is kept reasonably small.