RE: Re[2]: Re: Critically compare the congestion control on TCP/

[Paul Ferguson <[e-mail]>]

At 11:16 AM 03/09/2000 -0600, Schipper, Dell wrote:

>I recall that Larry Roberts a few years ago gave presentations (at
>NetWorld+InterOp ?) that compared the congestion avoidance algorithms of
>ATM-ABR service to TCP/IP.  I know he has started a new company since
>then and I do not have any contact information.

One of my favorites along those lines was:

"End-to-End Traffic Management Issues in IP/ATM Internetworks,"
draft-jagan-e2e-traf-mgmt-00.txt, S. Jagannath and N. Yin,
August 1997.

- paul

[snip]

Abstract

    This document addresses the end-to-end traffic management issues in
    IP/ATM internetworks. In the internetwork environment, the ATM
    control mechanisms (e.g., Available Bit Rate (ABR) and UBR with Early
    Packet Discard (EPD)) are applicable to the ATM subnetwork, while the
    TCP flow control extends from end to end. We investigated the end to
    end performance in terms of TCP throughput and file transfer delay in
    cases using ABR and UBR in the ATM subnetwork. In this document, we
    also discuss the issue of trade-off between the buffer requirements
    at the ATM edge device (e.g., Ethernet-ATM switch, ATM router
    interface) versus ATM switches inside the ATM network.

    Our simulation results show that in certain scenarios (e.g., with
    limited edge device buffer memory) UBR with EPD may perform
    comparably to ABR or even outperform ABR. We show that it is not
    sufficient to have a lossless ATM subnetwork from the end-to-end
    performance point of view. The results illustrate the necessity for
    an edge device congestion handling mechanism that can couple the ABR
    and TCP feedback control loops.  We present an algorithm that makes
    use of the ABR feedback information and edge device congestion state
    to make packet dropping decisions at the edge of the ATM network.
    Using the algorithm at the edge device, the end-to-end performance in
    throughput and delay are improved while using ABR as the ATM
    subnetwork technology and with small buffers in the edge device.

[snip]