RE: heads up - NetApp, NFSv4, and UDP

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From: Noveck, Dave (Dave.Noveck@netapp.com)
Date: 11/25/02-04:15:10 PM Z


Message-ID: <C8CF60CFC4D8A74E9945E32CF096548A072962@SILVER.nane.netapp.com>
From: "Noveck, Dave" <Dave.Noveck@netapp.com>
Subject: RE: heads up - NetApp, NFSv4, and UDP 
Date: Mon, 25 Nov 2002 14:15:10 -0800

Sometimes what comes for free has hidden costs.

In particular, if you use the same rpc that comes with v3,
you are going to be re-issuing requests on TCP connections,
under cirsumstances in which the v4 spec (section 3.1.1) says
you MUST NOT do so:

   When processing a request received over a reliable transport such as
   TCP, the NFS version 4 server MUST NOT silently drop the request,
   except if the transport connection has been broken. Given such a
   contract between NFS version 4 clients and servers, clients MUST NOT
   retry a request unless one or both of the following are true:

   o    The transport connection has been broken

   o    The procedure being retried is the NULL procedure 

As well as the free UDP, which seems to cause you to violate
section 3.1 of the spec:

   Where an NFS version 4 implementation supports operation over the IP
   network protocol, the supported transports between NFS and IP MUST be
   among the IETF-approved congestion control transport protocols, which
   include TCP and SCTP.

It says "the supported transports" (which I read as meaning all of them),
must be among a set in which UDP is clearly not included.  This is the result
of the final edits requested by the IESG.  So the spec says don't support
UDP, free or not.

  
-----Original Message-----
From: Jim Rees [mailto:rees@umich.edu]
Sent: Monday, November 25, 2002 4:56 PM
To: nfsv4-wg@sunroof.eng.sun.com
Subject: Re: heads up - NetApp, NFSv4, and UDP 


Our BSD client and server will do both.  We're using the rpc that came with
the NFSv3 client and server (plus rpcsec_gss), so we get udp for free.


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