Re: comment on intel i-d on h323 and internet
huitema@bellcore.com (Christian Huitema) Wed, 05 March 1997 23:00 UTC
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Date: Wed, 05 Mar 1997 17:59:44 -0500
From: huitema@bellcore.com
Message-Id: <9703051759.ZM23909@seawind.bellcore.com>
In-Reply-To: Jon Crowcroft <J.Crowcroft@cs.ucl.ac.uk> "comment on intel i-d on h323 and internet" (Mar 5, 5:54pm)
References: <29079.857584472@cs.ucl.ac.uk>
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To: Jon Crowcroft <J.Crowcroft@cs.ucl.ac.uk>, confctrl@isi.edu
Subject: Re: comment on intel i-d on h323 and internet
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Last time I counted, doing RAS + q931 + H245 implied :
1 RTT for RAS,
3 RTT for q931:
1 for the TCP SYN,
1 for the TP0 SYN in RFC1006
1 for the q931 call set up
4 RTT for h245:
1 for the TCP SYN
1 for TP0
1 for the capacity exchange
1 for the channel open
which implies 8 RTT before you set up, say, a telephone call. The
current Internet RTT for a long distance transmission is at best 100 ms,
more likely 200. So, we are speaking of 0.8 to 1.6 seconds to set up
the call. If you have any transmission error, you have to add 4 seconds,
i.e. the initial timer estimate of TCP. and we can certainly expect
quite a few errors on long distance transmissions...
--
Christian Huitema
- comment on intel i-d on h323 and internet Jon Crowcroft
- Re: comment on intel i-d on h323 and internet Christian Huitema
- Re: comment on intel i-d on h323 and internet Jon Crowcroft