Subject: proposed text for last call issues04 (transport)

From: Mike Eisler <[email-masked]>
Date: Thu, 29 Aug 2002 11:00:42 -0700

A suggestion has been made that the statement in section
3.1 about the use of TCP or transport with congestion
control needs to be updated. The text in question is:

   The transport used by the RPC service for the NFS
   version 4 protocol MUST provide congestion control
   comparable to that defined for TCP in [RFC2581].
   If the operating environment implements TCP, the NFS
   version 4 protocol SHOULD be supported over TCP.

A suggestion by our AD has been made to incorporate
something like the following.

    "TCP, SCTP or other IETF-approved congestion control
    transport protocol"

[ With apologies to Marshall Rose, soap box starts ...

BTW, at the last bakeoff, there was one server
implementation that had a bug preventing operation over
UDP, and as a result, worked only over TCP for the duration
of the bakeoff. By the time I left Ann Arbor on Thursday,
only one client had tested against it, because only one
had TCP working.

I don't know why we aren't allowed to simply say, TCP MUST
be supported. I believe that until we do, and until we
explicitly ban UDP we'll be stuck with interoperability
problems.

Do people really want to spend the resources to test and
support both TCP and UDP?

... soap box ends ]

--------------

CHANGE:

   The transport used by the RPC service for the NFS version 4 protocol
   MUST provide congestion control comparable to that defined for TCP in
   [RFC2581].  If the operating environment implements TCP, the NFS
   version 4 protocol SHOULD be supported over TCP.  The NFS client and
   server MAY use other transports if they support congestion control as
   defined above and in those cases a mechanism may be provided to
   override TCP usage in favor of another transport.

TO:

   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.  To enhance the possibilities for
   interoperability, an NFS version 4 implementation SHOULD
   support operation over the TCP transport protocol.

DELETE:

   [RFC2581]
   Allman, M., Paxson, V., Stevens, W., "TCP Congestion Control",
   RFC2581, April 1999.

   http://www.ietf.org/rfc/rfc2581.txt

---

From: Scott Bradner <[email-masked]>
Date: Thu, 29 Aug 2002 15:18:05 -0400 (EDT)

note that the AD did not suggest the text as a way to preserve UDP as an option
(the AD also thinks it should go away) 

in fact the idea behind the text is to say that UDP is not OK
while at the same time letting future development be done to
run NFS over SCTP, which might have some advantges

Scott

ps - nice rant though

-----

---

From: RJ Atkinson <[email-masked]>
Date: Thu, 29 Aug 2002 16:18:21 -0400

On Thursday, Aug 29, 2002, at 15:18 America/Montreal, Scott Bradner 
> run NFS over SCTP, which might have some advantges

BAD idea to promote NFS/SCTP because it will screw up interoperability.
We need to keep the options minimal and NFS/TCP has been demonstrated
to work really well.

STRONGLY DISAGREE.

Ran
[email-masked]

---

From: RJ Atkinson <[email-masked]>
Date: Thu, 29 Aug 2002 16:17:03 -0400

> support both TCP and UDP?

I'm not necessarily in favour of prohibiting UDP support.
I am STRONGLY in favour of making NFS/TCP support mandatory
to implement and mandatory to interoperability test.

As a user, I REALLY REALLY need NFS/TCP to just work reliably.
Period.

I find that NFSv3/TCP works better than NFSv3/UDP even on my
local LAN (and we make 10 Gig Ethernet switches, so my local
LAN is not congested).  I find that NFSv3/TCP is essential to
making my wide-area (VA<-->RTP; VA<-->SFBA) NFS sessions work
-- UDP is a non-starter operationally over my long-haul links
(my WAN links are rather lower bandwidth -- as noted in previous
notes to this list).

[RANT ON]
Mumbling about SCTP just isn't helping me operationally, because
I'll inevitably end up with some boxes supporting NFS/UDP only,
some with NFS/TCP only, and others with NFS/SCTP only -- which
means I won't have full interoperability of all boxes claiming
to support NFSv4.  The proposed new words Mike quoted are a
very sad joke.
[RANT OFF]

So if the AD is prohibiting us from saying that NFS/TCP is mandatory
to implement, then I'd suggest that we appeal that AD edict
-- on interoperability/deployment/operations grounds.

Mumble.

Ran
[email-masked]

---

From: Spencer Shepler <[email-masked]>
Date: Thu, 29 Aug 2002 17:13:17 -0500

>    support operation over the TCP transport protocol.

I would not be opposed to making TCP a MUST implement.

-- 
Spencer