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From: da@bvax.UUCP (Dave Sellers)
Newsgroups: comp.os.vms
Subject: Re: DECServer-200 Intercommunication
Message-ID: <259@bvax.UUCP>
Date: Wed, 16-Sep-87 12:37:52 EDT
Article-I.D.: bvax.259
Posted: Wed Sep 16 12:37:52 1987
Date-Received: Sat, 19-Sep-87 18:45:28 EDT
References: <870912093131.026@Lbl.Arpa>
Organization: Bell Canada, Toronto, CANADA
Lines: 49
Summary: More question re the DECServer-200 and point to point non DEC applications (as a network carrier).

In article <870912093131.026@Lbl.Arpa>, nagy%warner.hepnet@LBL.ARPA writes:

> Besides ports on DS200's being able to "originate" connections, ports can
> be declared to be services which can "receive" incoming connections.  This
> can be used for:
> 
> 	- "Reverse LAT" to connect to a host computer which does not support
> 	  the LAT protocols on Ethernet but which has async terminal lines
> 	  which can be connected to a DS200.
> 
> 	- Outgoing modem connections.
> 
> 	- Printers.
> 
> In all of the above cases, these items are declared as "services" by
> the DS200 which hosts the ports.  
> 
This talk has raised a couple of questions (I'm not a DECnet user):

1) If you wanted to use a port on the 200 for a point to point async
port (non-DEC to non-DEC host) could you,

a) tell the 200's to make a connection from one port to the other
from a remote location or must you be connected to the 200 via a terminal
to initiate the connection?

b) will the connection stay up forever?

c) if a communications link failed between LAN's would the connection
be rerouted via another link (if one existed) automatically?

2) It was stated that a "service" must be created so that a port can be
accessed. 

a) Is there a limit to the number of services (ie. could it handle 3000+
services) (does this relate to 1 above)

b) Are all the services known to all users (if * permissions assumed)?

c) Does the connection to these services put a load on a VAX (somewhere)?


In summary, is there a problem with using DECnet as a replacement for
point-to-point async communication lines (non-DEC)?

Dave Sellers
Manager - Peripheral Systems
Bell Canada
416-599-2085