Path: utzoo!attcan!uunet!lll-winken!ames!rex!uflorida!novavax!fenix!jmagee
From: jmagee@fenix.UUCP (Jim Magee)
Newsgroups: comp.dcom.lans
Subject: Re: TCP/IP Socket to X.25 Gateway?
Message-ID: <2283@fenix.UUCP>
Date: 11 May 89 16:13:48 GMT
References: <416@tdmfed.UUCP>
Organization: Gould CSD, Fort Lauderdale, FL
Lines: 38
In-reply-to: rbr@tdmfed.UUCP's message of 1 May 89 15:33:54 GMT


>Hello,
>We have a customer developing a Unix-based application which must communicate
>over X.25 to host applications.  Since there are several different Unix
>machines involved in the solution (not all with compatible X.25 programmatic
>interfaces) I was wondering if anyone knew of a TCP/IP to X.25 Gateway
>product that documented the interface, so that a socket interface on the 
>Unix system could access X.25 packets?  This, it seems to me, would keep the
>customer's development interface standard (TCP/IP sockets) and let an
>external box handle the X.25 interface. (Ethernet TCP/IP to X.25)

I has attempted to do this about a year ago to the SunLink X.25 from
several different Unix boxes.  I just used the Sun RPC code (all the 
machines I was working with had NFS) to implement the X.25 interface
calls. 

I only ran into one are that really didn't fit this model.  The SunLink
X.25 sockets hand back "out of band" data at several different levels.
X.25 resets had the highest priority level.  Trying to implement this
feature using TCP/IP sockets (single level Out of Band Data) was very
difficult.  But since handling of X.25 reset is in itself a difficult
thing at best, this just put one more fly into the ointment.

The result was a slightly less that transparent interface, but it was
good enough (I was trying to provide a generic interface for people to
code to, and something like this can be a show stopper for some 
appliations)

-Jim
+-------------------------------+---------------------------------------+
| Jim Magee - Unix Development	| Encore Computer Corp 			|
| jmagee@gould.com		| 6901 W Sunrise Blvd  MS407		|
| ...!gould!jmagee		| Ft Lauderdale, FL 33313		|
|				| (305) 587-2900 x4925			|
+-------------------------------+---------------------------------------+
| DISCLAIMER:	The opinions expressed here do not represent those of	|
| 		Gould or Encore, even if I knew what those were.	|
+-----------------------------------------------------------------------+