A Simulation Study of TCP Traffic Control over ATM ABR Flow Control.
[Abstract] | [Download Postscript File]
TCP over ATM is a cheaper way to migrate from TCP/IP to ATM. LAN Emulation and IP over ATM are such two products. ATM provides ABR and UBR services for high layer to transfer data. ABR service has a flow control mechanism, but UBR service does not.
In this work, we simulate and investigate the dual control, that is TCP traffic control on TCP layer and ABR flow control on ATM layer. First, we observe that TCP traffic control and ABR flow control cannot cooperate well. The most worst is that the slow start after packet loss will cause unused high ACR and switch queue under-flow. We suggest to implement a use-it-or-lost-it policy and fast recovery to avoid these phenomena. A simple use-it-or-lose-it policy is simulated to see its improvement. We also limit the buffer size of source ABR queue to see its impact on flow control. Finally, we examine the effect of maximum segment size, receiver window buffer, and rate increase factor on the performance of TCP traffic control over ABR flow control.
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