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- Xref: sparky comp.client-server:244 comp.sys.sun.misc:5927
- Path: 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
- Lines: 24
-
- 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."
-