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Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!mcvax!ukc!axion!fulcrum!igb
From: igb@Fulcrum.BT.CO.UK (Ian G Batten)
Newsgroups: comp.dcom.modems,comp.mail.uucp
Subject: UUCP over X25 [Was Re: Telebits and uucp g-protocol]
Keywords: Telebit Trailblazers, g-protocol, uucp
Message-ID: <193@cat.Fulcrum.BT.CO.UK>
Date: 14 Jun 89 11:21:17 GMT
References: <335@nixtor.UUCP> <10391@smoke.BRL.MIL> <1989Jun12.185746.7217@eci386.uucp>
Reply-To: igb@fulcrum.bt.co.uk (Ian G Batten)
Organization: BT Fulcrum, Birmingham, England
Lines: 28

In article <1989Jun12.185746.7217@eci386.uucp> clewis@eci386.UUCP (Chris Lewis) writes:
>
>G-protocol does work over X.25 with PADS.  The main difficulty (not counting
>cost and "how it god's name do I configure the PAD to allow this?!" for the 
>moment) is the end-to-end-to-end delays.  At 9600 baud, you
>can send 3 64 byte packets in 200-ish ms.  Then you add the 50 ms. timeout
>to send the ack packet back, plus X.25 gateway delays, plus network
>turnarounds, plus satellite links etc.  Yuck.  When we tested 9600 X.25/PAD
>links with G, we got 600 baud effective thruput.  And that was simply bouncing
>it off our local X.25 connection 5 miles away.  Cross country was more like 
>60 baud.

This may be a difference between US and UK, but I find that UUCP over
X25 is basically OK.  I have a machine with a TB+, a pair of v22bis
modems and a 2400 bps X25 line.  I see 245 cps with the 'e' protocol
from HoneyDanber (interestingly, 'x' doesn't seem to work for me!) and
perhaps about 140 for 'g' protocol.  This is for a newsfeed over about
100 miles.

[E protocol is pretty similar to 'f', but doesn't reduce the datawidth.
I've never tried shipping binary data over X25 with it.  As it gets us
full bandwidth of the line for our news feed, we aren't going to disturb
it.]

ian

-- 
Ian G Batten, BT Fulcrum - igb@fulcrum.bt.co.uk - ...!uunet!ukc!fulcrum!igb