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From: mishkin@apollo.HP.COM (Nathaniel Mishkin)
Newsgroups: comp.protocols.misc
Subject: Re: RPC Technologies
Message-ID: <1990Sep7.153916@apollo.HP.COM>
Date: 7 Sep 90 19:39:00 GMT
References: <1990Sep7.004206.17225@athena.mit.edu>
Sender: root@apollo.HP.COM
Reply-To: mishkin@apollo.HP.COM (Nathaniel Mishkin)
Organization: Hewlett-Packard Company - Cooperative Object Computing Operation
Lines: 58

In article <1990Sep7.004206.17225@athena.mit.edu>, pae@athena.mit.edu (Philip Earnhardt) writes:
>In earlier discussions on this group Mishkin has tried to discount the
>importance of Netwise's using ISO 8327 (Session Layer Protocol) and
>ISO 8822 (Presentation Layer Protocol) in its new products:
>
>If RPC is a Layer 7 protocol, the *exact* way that it would fit into a
>Profiled OSI Stack is on top if the standard OSI Presentation and
>Session layers.
>
>Several quesitons:
>
>1. Do the NCS developers think that OSI RPC is going to be a layer 7
>   standard? If not, why not? 

To the extent I understand all this, yes.

>2. If the answer to #1 is yes, what protocols do they think will be used
>   at Layer 6 and Layer 5? If not ISO 8327 and ISO 8824, what other
>   protocls will be used?

I don't get it.  The fact that you use ISO standard Session and
Presentation layer protocols is merely interesting, not important in
achieving an RPC system that meets some standard, because there IS no
RPC standard at the higher levels.  Whatever you (or we) do at those
layers does not yield a "standard RPC", regardless of whether we happen
to use standard protocols at lower levels.

To the extent that you use standard protocols at lower levels and to
the extent that it's hard to produce (or find existing) systems that
implement or use those protocols, you may have some advantage in the
race to achieve a standard RPC system, when the higher-level protocols
are standardized.  My supposition is that implementation of the session
layer protocols is the business of the platform upon which I'm building
an RPC system and that there are a variety of existing implementations
of ASN.1/BER that I could freely obtain or buy to use as the basis for
the presentation level implementation of my RPC system.  It's just not
that big a deal, and the requirement is not going to appear tomorrow
(because the RPC standard is not going to appear tomorrow).

>3. Your second sentence above talks about NCS on top of COTPs. What
>   about NCS on top of CLTPs? Will these be ISO compliant? Will they
>   use the ISO connection-oriented or connectionless upper layer protocols?

As I understand things, whether I can build an NCS that is an RPC system
that is ISO compliant and runs over CLTP's is a function of whether ISO
defines upper level RPC protocols that are defined to work on top of
CLTP's.  I think ROSE is defined to use COTP's.  I suspect that any ISO
standard RPC will be similarly defined (although maybe other ISO standard
RPC protocols will be defined later to run over CLTP's).  When a
CLTP-oriented ISO RPC protocol is defined, I imagine we will implement
it.  It's hard to be concrete about things that depend on things that
don't exist.

--
                    -- Nat Mishkin
                       Cooperative Object Computing Operation
                       Hewlett-Packard Company
                       mishkin@apollo.hp.com