topic Re: Converting an x25 access app to TCPIP in Operating System - OpenVMS

Converting an x25 access app to TCPIP

Douglas Fisher — Sat, 12 Aug 2006 17:32:30 GMT

We have an application that needs to be converted to use tcpip. As with x25 the incomming connection needs to create the job, invoke the app and the app must be able to continue detached after the connection is dropped. Then end after finishing processing.

I've looked through the doc's and havn't found much.
Can anyone out there help?

Re: Converting an x25 access app to TCPIP

Jan van den Ende — Sun, 13 Aug 2006 04:48:28 GMT

Douglas,

the (rather) easy way is to switch to DECnet-overIP. Essentially you reconfigure DECnet to use IP as carrier instead of X25.
Trying to replace --DECNET-- with various IP utilities is essentially a re-write of the networking functionalities of all your apps.

-- maybe a crude first approximation, but is IS threat devider between two possible ways to go.

hth

Proost.

Have one on me.

jpe

Re: Converting an x25 access app to TCPIP

Jan van den Ende — Sun, 13 Aug 2006 04:51:40 GMT

WHAT AN UGLY TYPO!!

but is IS threat devider

dhould have been
but is IS the great devider

sorry..

Proost.

Have one on me.

jpe

Re: Converting an x25 access app to TCPIP

Volker Halle — Sun, 13 Aug 2006 04:51:47 GMT

Douglas,

as long as the app does not try to read/write on the TCPIP socket after the client has disconnected or treats the disconnect as a fatal error, there should be not much of a problem to rewrite your X.25 application to use e.g. TCPIP sockets.

There is even an example in TCPIP$EXAMPLES:

TCPIP$TCP_SERVER_SOCK_AUXS.C

Volker.

Re: Converting an x25 access app to TCPIP

Jan van den Ende — Sun, 13 Aug 2006 05:49:10 GMT

Volker,

that is one of the main reasons I would prefer tp continue using DECnet:
DECnet has all kinds of error handling in it automagically.
Those handlings are also possible in TCPIP, but YOU HAVE TO CODE THEM EXPLICITLY IN YOUR CODE.
We found out the hard way. some 5 years ago. It was decided (against the advice of several techies including myself) to abondon DECnet altogether and _NOT_ allow DECnet-over-IP (can you imagine: for security reasons!).
Well, the rock-solid connections we were used to had quite gone. Over time the most apps now have error hanfling added, but the cost has been tremendius, and we are still (after 5 years!) not really at the level we used to be.

But, given that politics is more important than money, or user satisfaction, the project WAS declared an enormous succes. (the organisation now save 5 % of the changeover cost annually!)

Just our experience, YMMV !!

Proost.

Have one on me.

jpe

Re: Converting an x25 access app to TCPIP

Volker Halle — Sun, 13 Aug 2006 06:48:59 GMT

Jan,

if this is a native X.25 access application, DECnet may not even be involved, so I don't see, how DECnet-over-IP could be used to replace the X.25 connection.

If it would be DLM (Data Link Mapping = DECnet over X.25), then replacing this with DECnet-over-IP might even be transparent to the application.

Let's see what Douglas has to say...

Volker.

Re: Converting an x25 access app to TCPIP

Jan van den Ende — Sun, 13 Aug 2006 07:03:32 GMT

Yes, Ok.

My experience is limited to DECnet-over-IP, so, if for Douglas that is not the case, my answers so far do not apply, and I have no opinion either way.

Proost.

Have one on me.

jpe

Re: Converting an x25 access app to TCPIP

john Dite — Mon, 14 Aug 2006 13:41:26 GMT

I can't comment on your application, but there is an alternative, and that is to use an X.25 to TCP Gateway.

See
http://www.funkwerk-ec.com/scripts/info_cd/en/solutions/50-ss_tcp_to_x25_gw_1-en.pdf

However I don't know how well represented the company is in the US.

They built in this feature as a special request from a large Telco provider here in Germany, so it must work.

I've used these Router/Gateways in the past to replace old Digital DECNIS routers by using XOT instead of GAP. In the past their solutions were also popular because it enabled X.25 customers to use X.25 over ISDN without changing the backend configuration bar the calling #.

Hope this helps.

John

Re: Converting an x25 access app to TCPIP

Douglas Fisher — Mon, 14 Aug 2006 13:48:54 GMT

Thanks to everyone who has replied.
The app is native x25.

Re: Converting an x25 access app to TCPIP

john Dite — Mon, 14 Aug 2006 13:55:37 GMT

If you're interested I could get you some english documentation. Let me know.

John

Re: Converting an x25 access app to TCPIP

Richard J Maher — Tue, 15 Aug 2006 08:15:58 GMT

Hi Douglas,

You didn't stipulate whether or not your server needed to handle multiple simultaneous requests; this would make a difference. But if you're happy with INETd here's a $QIO example in a language that's easy to understand.

Regards Richard Maher

Re: Converting an x25 access app to TCPIP

Douglas Fisher — Wed, 16 Aug 2006 13:37:07 GMT

Found a work around using llc2 as a transport. This is a very old app that had some quirks we had to discover before we could get it to answere.

Thanks to everyone for the help, even though I didn't use the info this time I will certainly be using it soon.