An agent based congestion control and notification scheme for TCP over ABR

✍ Scribed by K Djemame; M Kara; R Banwait

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 445 KB
• Volume: 23
• Category: Article
• ISSN: 0140-3664
• DOI: 10.1016/s0140-3664(00)00193-6

✦ Synopsis

We overview in this paper the enhancement of TCP's congestion control mechanisms using Explicit Congestion Notification (ECN) over ATM networks. Congestion is indicated by not only packet losses as is currently the case but an agent implemented at the network's edge as well. The agent bridges the gap between the ATM layer and the TCP layer in the protocol stack at the receiver end and coordinates the congestion control algorithms of the TCP transport protocol and the ATM cell-oriented switching architecture. The novel idea uses ABR rate-based flow control to notify congestion and adjust the credit-based window size of TCP.

The effects of running TCP ECN over ABR (Available Bit Rate) are studied with the help of two simulation models (LAN and WAN). The simulation results indicate that LANs having a single switch and WANs with multiple switches benefit most from TCP ECN. In almost all scenarios, TCP ECN achieved significantly lower cell loss, packet retransmissions, buffer utilisation and exhibited better throughput than TCP Reno.