I am evaluating feasibility of the following setup:
Public
Sun workstation Data Network Sun workstation
____________^______________ _____^______ ____________^_____________
/ \ / \ / \
INGRES-NET SunLink X.25 PDN SunLink X.25 INGRES-NET
appl. rexec <-> TCP/IP <-> X.25 <-> X.25 PDN <-> X.25 <-> TCP/IP <-> rexec appl.
One of the Suns is to be based in Europe, the other in Australia.
INGRES-NET I am told issues rexec calls to the remote peer. They are
encapsulated into TCP/IP datagrams and then passed to SunLink X.25
software which sends them as X.25 packets out to a PDN interface (9.6 kb/s
synchronous). On the other end SunLink X.25 retrieves TCP/IP packets. They
then deliver the rexec information to INGRES-NET on the other end. (In
fact the other INGRES-NET does not have to run on the Sun - it may run on
another UNIX host on the local network.)
In principle everything should work fine. But there are countless
questions. What about virtual call establishment and clearing? With the
distance involved just keeping the call open when not needed may be quite
costly. Is the SunLink software smart enough to open such a call
automatically after receiving first packet to be forwarded trough the
link? What about delays? Won't that timeout in any of the higher layers?
By the way I know that the TCP/IP to X.25 conversion can be done in a
hardware box (CS/150 will do I think). Use of Sun workstations is much
prefered in this case as they will be there anyway to run some other
applications. Only if this setup does not work another solution may be
considered.
I am pretty sure somebody tried similar setup before. Dear netters, I will
greatly appreciate your comments, descriptions of your experiences (both
positive and negative), pointers to other sources of information etc. I
prefer to receive responses by email. I will summarize to the net.
Chris Jankowski chris at yarra.oz.au chris at yarra.oz
Pyramid Technology Australia - Melbourne