[comp.dcom.lans] IP to DECNET translation ????

matt@oddjob.UChicago.EDU (Matt Crawford) (05/13/87)

Help!  We want to connect our campus IP networks to SPAN, a wide
area decnet network run by NASA.  At the moment our sole SPAN
node is a PDP-11 with a 9600 baud leased line.  We will shell
out for a microvax if we can put some sort of software on it
that will provide access from TCP as transparently as possible.

Is there anything which will give us better access than just
logging in to the span node?  Some people will want to transfer
very large data sets and buying enough scratch disk for them
would be an obstacle.  Most users don't want to learn VMS (and
DECNET/Ultrix only supports ethernet as an interface).

What we wish for is a protocol translator.  Is there one?
________________________________________________________
Matt	     University		matt@oddjob.uchicago.edu
Crawford     of Chicago     {astrovax,ihnp4}!oddjob!matt

ejnorman@uwmacc.UUCP (Eric Norman) (05/14/87)

In article <3770@oddjob.UChicago.EDU>,
matt@oddjob.uchicago.edu (Matt Crawford) pleads for mercy with:

> Help!  We want to connect our campus IP networks to SPAN, a wide
> 
> Is there anything which will give us better access than just
> logging in to the span node?  Some people will want to transfer

I just copied a file from a DECnet host to an IP host using
a MicroVAX running Ultrix as an intermediary with

  rsh ultrix-host dcat decnet-node::vms-file > unix-file

All I needed was an .rhosts file on the Ultrix beast.  A proxy
account on the DECnet node does not seem to allow referencing a
file relative to your home directory; i.e., the following failed:

  rsh ultrix-host dcat decnet-node::login.com

However, this does work after an rlogin to the Ultrix host:

  dcat decnet-node::login.com | rsh unix-host put vms-login-file

where my .cshrc on unix-host aliases "put" to "cat - >".

Now, methinks you would want to write some simple shell scripts
to do all that, but I reckon you would want to do that anyway
so that folks don't have to learn VMS.

> What we wish for is a protocol translator.  Is there one?

Heffalumps.  See RFC875; such a critter operating at the network
or transport layer would probably be considered miraculous.
However, up at the presentation or application layer it seems at
least partly possible.  Gatewaying mail from DECnet squawkers to
IP barkers isn't difficult, albeit without complete protocol
translation.  The above would be another example of the possibilities.

I think one of the nice things about the .rhosts or proxy account
approach is that they allow you hide the fact that you're rising higher
up the protocol stack.

Eric Norman
Internet:     ejnorman@unix.macc.wisc.edu
UUCP:         ...{allegra,ihnp4,seismo}!uwvax!uwmacc!ejnorman
Life:         Detroit!Alexandria!Omaha!Indianapolis!Madison!Hyde
  
"And on the eighth day He said, 'Oops'."	-- me
--

melohn@sluggo.UUCP (05/17/87)

In article <1505@uwmacc.UUCP> ejnorman@unix.macc.wisc.edu.UUCP (Eric Norman) writes:
>
>I just copied a file from a DECnet host to an IP host using
>a MicroVAX running Ultrix as an intermediary with
>
>  rsh ultrix-host dcat decnet-node::vms-file > unix-file
>

We do this all the time with our Sunlink DNA gateway. I define the following:

alias sethost  on -i dna-gateway dnalogin !$

in my .cshrc, and then can remotely login from any Unix node in our internet
to any DECnet node accesable via the Sunlink DNA DECnet gateway "dna-gateway"
with the following command:

sethost decnetnode

Similar aliases can be setup for file transfer, the "on" utility
exporting your filesystem enviornment to the gateway machine via NFS, which
is handy when you are transfering multiple files.