[e2e] TCP un-friendly congestion control

[Injong Rhee]

Hi Ibrahim,

Please correct me if I am wrong (I read the previous version of your
SIMD paper -- I haven't read your newer version). I like the paper and
especially, the fact it utilizes history and its t^2 behavior. However,
the protocol seems to target to match TCP throughput under a loss rate p
by adjusting its CC parameters (alpha and beta).  But if it matches TCP
throughput under loss rate p, then I am not sure how it can perform
better than TCP under fast, long distance networks (where it is known
that TCP is not doing well) while being fair (or compatible) to TCP.
Maybe I need to read your paper again. Sorry if I am wrong. 

Just curious and lazy...

Injong Rhee
Computer Science Dept
North Carolina State Univ.
rhee at csc.ncsu.edu
http://www.csc.ncsu.edu/faculty/rhee

-----Original Message-----
From: Ibrahim Matta [mailto:matta at cs.bu.edu] 
Sent: Friday, June 06, 2003 12:59 PM
To: Injong Rhee
Cc: 'Tom Kelly'; 'Michael Welzl'; end2end-interest at postel.org
Subject: Re: [e2e] TCP un-friendly congestion control

Injong Rhee wrote:
> Hi.
> 
> It is my understanding that in the environments where these protocols
> (HSTCP, Scalable TCP, and FAST) are intended to operate -- fast
(>1Gbps)
> and long distance networks (>50ms) -- TCP friendliness is not a
concern
> since TCP cannot fully utilize the available network bandwidth. These
> protocols try to overcome this under-utilization problem of TCP.
> However, if we try to apply this to the general Internet environments
> (as it is noted in the announcement by CalTech), I think there could
be
> some TCP-fairness issues.
> 

It is possible to design more aggressive protocols
that are also TCP-friendly. E.g. see our
history-based SIMD proposal at

http://csr.bu.edu/simd/

A wider class is defined in:

http://www.cs.bu.edu/techreports/pdf/2002-027-spectrum-tcp-friendly.pdf


Best regards, ibrahim

-- 
--
Ibrahim Matta       Dept of Comp Sci, 111 Cummington St, MCS-271
matta at cs.bu.edu     Assoc Prof, Boston Univ., Boston, MA 02215
Tel: (617)358-1062, Fax: (617)353-6457, URL: www.cs.bu.edu/fac/matta/