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From: andrew@mitisft.UUCP
Newsgroups: comp.protocols.tcp-ip
Subject: Re: dial-up SLIP
Message-ID: <269@mitisft.Convergent.COM>
Date: Fri, 20-Nov-87 17:33:10 EST
Article-I.D.: mitisft.269
Posted: Fri Nov 20 17:33:10 1987
Date-Received: Sun, 22-Nov-87 16:52:17 EST
References: <8711192329.AA03145@ucbvax.Berkeley.EDU>
Organization: Convergent Technologies, San Jose, CA
Lines: 40

in article <8711192329.AA03145@ucbvax.Berkeley.EDU>, craig@NNSC.NSF.NET (Craig Partridge) says:
> 
> 
> At CSNET we're experimenting with an idea which is close to this.
> 
> The basic idea is that when an IP packet hits our gateway destined
> for a remote machine  we make a phone call, establish the link, and
> keep it running as long as there is continued traffic.  When the
> traffic stops, we shut down the line.
> 

	We've had dial-up SLIP running for over a year internally
here at Convergent, initially on a more-or-less straight 4.3 port
and currently on a Streams port.

	It works, basically, by having a deamon which is woken up
when the routing code chooses a "dialed" (more generally, switched)
route.  It then calls into a bunch of UUCP code to establish the
connection, and logs in to an account which runs the daemon in
"server mode".  The "client" then informs the "server" of who he is
(ascii), his numeric address, and what he thinks the server's numeric
address is. The server checks his host and authentication files, they
synchronize and slattach, and the deferred packets are sent.
After that its peer-peer, until a timeout occurs with active TCP
or carrier loss.

	I still consider this to be in the experimental phase, primarily
in the routing area.  Currently the system uses the "gateway" model;
no net number is assigned to the link itself, an each system sort of
thinks it has an interface on the nets connected to the remote.

	The inital connection protocol is pretty crude -- just an exchange
of cute little text messages.  Eventually I'd like to add some simple
error checking, though the problems there have been minimal so far.
We use it over our PBX to comminiacte between biuldings here regularly,
at 19200 baud.

Andrew Knutsen
(408) 435-3623
I'm also planning on testing with the new high speed modems.