perl@pbseps.UUCP (Richard Perlman) (09/22/89)
This is probably a crazy question, but then that's often how new
products are born. In any case... Is there such a thing as a
translating gateway between TCP/IP and XNS? I have a specific
need, as follows: Site a runs TCP/IP and uses telnet to access
remote services on other hosts and terminal servers. Site b is
an XNS terminal server (UB NIU-180 or X.25 gateway), it runs
whatever sort of virtual terminal protocol UB provides with XNS
(whatever protocol you connect to when you type 'connect <host>'
from an NIU-180?).
I would like to use telnet at site a to talk to the server at
site b.
Site a Site b
+-------------+ telnet +---------+ UB xns ? +----------+
| tcp/ip host |=============| gateway |===============| niu-180 |
+-------------+ net A +---------+ net B +----------+
| ethernet ethernet |
my terminal remote service
So in other words (if I still havn't made my point clearly) I
would like the "remote service" attached to the NIU-180 to
appear to me as thought it were running telnet. Got it?
Well, is there such a thing. All reasonable replies accepted!
--
Richard Perlman * perl@pbseps.pacbell.com || {ames,sun,att}!pacbell!pbseps!perl
180 New Montgomery St. rm 602, San Francisco, CA 94105 |*| 1(415) 545-0233dcrocker@AHWAHNEE.STANFORD.EDU (Dave Crocker) (09/23/89)
(You're not going to like this...) What you need is something in the category, called "application gateway". You do not simply need translation between the transport-and-below lower layers, but rather have a difference at every level, except perhaps media. Hence, you need to translate every layer. In reality, this means that you need something that is "dual stack" running both ENTIRE sets of protocols and a translation device in between. For software application gateways, this normally means a single application, running on top of the two transport stacks, where the application does BOTH application protocols and translates between them. In this particular case, there is a different solution. It is the part you might not like: Take one XNS-based terminal server and one TCP-based terminal server and back them up to each other. Connect the serial ports. Play with it until the configurations are right. You now have a terminal protocol translator. Dave
jqj@RT-JQJ.STANFORD.EDU (JQ Johnson) (09/25/89)
As Dave Crocker points out, the safest way to get the remote terminal applications gateway you want is to put 2 terminal servers back to back. However, if you can get documentation on the XNS terminal protocol, you could also consider using a 4.3BSD system as the applications gateway. The problem here is that XNS is well defined up through transport, but above that each vendor has added its own suite of protocols. Xerox, for example, has an RPC system called Courier built on SPP (the reliable transport protocol that is the top of the traditional XNS stack). On Courier, Xerox has built many applications including a remote terminal protocol. Several years ago at Cornell, I built a remote terminal applications gateway running on a BSD system that used the XNS support in 4.3BSD, and hooked together a TCP telnet client (server) to an xnschat server (client) to provide exactly the kind of gateway you envisage. Unfortunately, that's for only *one* flavor of XNS-based remote terminal protocol, not yours! Although TCP/IP has not been very successful at being chosen as the native protocol for LAN operating systems, it has been far more successful than XNS in achieving multi-vendor interoperability. JQ Johnson voice: 415-723-3078 Manager, Special Projects Internet: jqj@jessica.stanford.edu Networking and Communications Systems Pine Hall Rm 125-A Stanford University Stanford, CA 94305-4122
"Juan_Navarro.XOSMAR"@XEROX.COM (09/25/89)
Xerox has a TCP/XNS gateway available that supports telnet, smtp and ftp. The gateway also supports name servers, host table addressing, mx domains and ip routers. This may not be exactly what you need though, since the gateway must be on the same e-net as both the TCP and XNS hosts. Your diagram appears to require some type of router in between these the different nets. If you need more information, drop me a line or call. ------------------------------------------------------------------------- Juan Navarro - Xerox Federal Goverment Operations (703) 247-6429