Sun RPC time-out question

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#169

From: Guido van Rossum
Date: Sat, 19 Dec 1992 11:29

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Is there an expert on Sun RPC in this group?

I am in the process of re-implementing Sun RPC.  All the documentation
I have are RFC1014 (XDR) and RFC1057 (RPC), and RFC1094 (NFS).  I have
a question that isn't answered by these documents:

When using the UDP version, how does the client recover from lost
packets?  When the call packet is lost, a simple retransmission is
enough, however, when a reply packet is lost, a retransmission can
cause the request to be executed twice.  How does e.g. an NFS client
handle this if the request is not idempotent (like RENAME)?  Is there
a way for the client to tell from the failing reply from the second
try that the first try must have succeeded even though the response
got lost?

Note that I need to know how the existing Sun RPC implementation
handles this situation, not how it could be done in a hypothetical
system (I know all about Amoeba's RPC, for instance).

Pointers to sources or documents are welcome!

--Guido van Rossum, CWI, Amsterdam <guido@cwi.nl>
"That was never five minutes just now!"
"I'm afraid it was."

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Path: arc1-ca.pugleaf.net!sparky!uunet!mcsun!sun4nl!cwi.nl!guido
From: guido@cwi.nl (Guido van Rossum)
Newsgroups: comp.client-server,comp.sys.sun.misc
Subject: Sun RPC time-out question
Message-ID: <8411@charon.cwi.nl>
Date: 19 Dec 92 11:29:21 GMT
Sender: news@cwi.nl
Followup-To: comp.client-server
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