(keitai-l) Re: TCP and i-mode

From: Curt Sampson <cjs_at_cynic.net>
Date: 06/27/02
Message-ID: <Pine.NEB.4.43.0206271915040.6613-100000@angelic.cynic.net>
On Thu, 27 Jun 2002, Ken Chang wrote:

> first, TCP has a curve to climb before it can explore and get right
> the available bandwidth, and this process is slow (10 secs?).

Where do you get your 10 second figure from?

> it's not the width of the channel but the stability of RTT that keeps
> the TCP climbing towards the maximum speed.

Can you explain the effect of RTT in this situation? This is not
exactly how I recall TCP working.

> DoCoMo's TCP version, TLP, performs maybe only 1/3 as the WAP stack
> in the worst case but on average maybe they can do 80%, because
> i-mode is mostly used "in a sofa-bed at home".

Well, there you go. 80% of the performance is not so awful now, is it?

> also, even in the fixed network, TCP has a lot of problems for
> streaming and signaling etc.

Would you care to describe these in detail?

> and we know most of them many years
> before UP and i-mode.  but there is still no universal solution
> yet to replace TCP, a not-so-good but great design.

And who is interested in replacing TCP? What charcteristics would a
"better" protocol have?

cjs
-- 
Curt Sampson  <cjs_at_cynic.net>   +81 90 7737 2974   http://www.netbsd.org
    Don't you know, in this new Dark Age, we're all light.  --XTC
Received on Thu Jun 27 13:21:37 2002