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From: ron@brl-sem.ARPA (Ron Natalie <ron>)
Newsgroups: net.dcom
Subject: Re: I have some questions about distributed computing standards . . .
Message-ID: <524@brl-sem.ARPA>
Date: Fri, 15-Nov-85 00:58:25 EST
Article-I.D.: brl-sem.524
Posted: Fri Nov 15 00:58:25 1985
Date-Received: Sat, 16-Nov-85 09:48:29 EST
References: <776@infopro.UUCP>
Organization: Ballistic Research Lab
Lines: 39

> Please write to tell me of file-server & vitrual terminal standards.  I
> know that DEC has them, SUN has them, and Xerox has them.

DEC uses DECNET, it's pretty well documented but no one outside of DEC
bothers.

SUN uses two different protocols.  The older one ND, is really the file
server protocol.  It runs on top of a protocol called IP (I'll get into
this later).  People outside of SUN know how this works.  NFS is a virtual
filesystem to allow multiple systems to share the same disks on a file by
file basis.  This is a protocol over TCP/IP, but SUN is very tight lipped
about telling anybody how this works.

Xerox protcols are based on their Ethernet protocol XNS.

>  Are there any
> other such standards?  Perhaps ARPA standards?  Are any of the standards
> multi-vendor or are they all proprietary?

The ARPA standards provide for several levels.  The lowest, the internet
protocol (IP) handles getting raw datagrams accross multiple dissimilar
networks.  Over this, the transmission control protocol (TCP) is used
to provide a reliable virtual circuit.  Finally, there are many application
protocols including virtual terminals (which is called TELNET).

> 
> Also, is there some sort of fault-tolerant inter-LAN gateway?  Something
> that would allow interconnection of two LANs & keep one going even if the
> other is completely dead?  (I'm aware that this should go in net.lan, but
> we don't get that group.)

The key to IP's popularity is that it will send packets transparently
across networks.  This is accomplished by a device called an Internet
Gateway.  It can either be a stand-alone system or incorporated into
a regular host (There are more 4.2 systems functioning as gateways than
all the other types of gateways combined).  I work with the protcols
as they apply to these gateways.

-Ron