[comp.protocols.misc] Has anyone tried NFS over SLIP?

rcsmith@anagld.UUCP (Ray Smith) (10/14/89)

The subject says it all. I would like to hear from anybody that has tried
this. I was asked the question and have no idea if it is even possible.

Thanks in advance,
Ray
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dyer@spdcc.COM (Steve Dyer) (10/15/89)

In article <731@anagld.UUCP> rcsmith@analytics.com (Ray Smith) writes:
>The subject says it all. I would like to hear from anybody that has tried
>this. I was asked the question and have no idea if it is even possible.

Well, sure it's possible on most NFS implementations where the network
supports SLIP, but it's not very pleasant.  Be sure that UDP checksumming
is turned on in your kernel (for most BSD-derived systems, that means the
variable 'udpcksum' should be set to 1.)  Because the SLIP link level has
no checksum, line noise can easily corrupt a packet (and over an NFS mount,
corrupt your files.)  I'd also adjust your rsize and wsize mount parameters
to something smallish.

I have a 19.2kb SLIP line as my connection to the Internet, and have
occasionally mounted file systems located several gateways away.
It works.  I don't use it routinely for read/write work.  I find it
most useful for mounting read-only filesystems which have files I
occasionally refer to by name (Athena's 'xpix' bitmap locker, etc.)

-- 
Steve Dyer
dyer@ursa-major.spdcc.com aka {ima,harvard,rayssd,linus,m2c}!spdcc!dyer
dyer@arktouros.mit.edu, dyer@hstbme.mit.edu

vjs@rhyolite.wpd.sgi.com (Vernon Schryver) (10/15/89)

In article <731@anagld.UUCP>, rcsmith@anagld.UUCP (Ray Smith) writes:
> 
> ...[is NFS possible over SLIP]...

Yes, provided you either (1) get NFS clients and servers that turn
on UDP checksums or (2) use a SLIP varient that does end-to-end checksumming
(or equivalent).

However, it's not pretty.  Think about the sizes of "small" NFS traffic
like attribute requests.  If you value your lunch, do not think about
distant hosts doing 8KB UDP's without knowing there is a SLIP 9.6Kb gateway
in the route.  It stops being funny at <9.6.


Vernon Schryver
Silicon Graphics
vjs@sgi.com

craig@com2serv.C2S.MN.ORG (Craig S. Wilson) (10/16/89)

In article <731@anagld.UUCP> rcsmith@analytics.com (Ray Smith) writes:
>The subject says it all. I would like to hear from anybody that has tried
>this. I was asked the question and have no idea if it is even possible.
>Thanks in advance,
>Ray
>-- 

We have set up a Convergent S/80 using a direct SLIP connection to
another S/80 which is on our network.  We have been able to mount
directories both ways. We've mounted the SLIP'ed S/80's directories 
on other network computers, including PCs.  We also can mount other 
computer's directories (SUN 3/260, 3/280, 2/60) on the SLIP'ed S/80.

We have had some problem connecting the S/80 to a SUN via SLIP because
of some fundamental philosphical differences in the implementations.
It may be possible, but we have taken the path of least resistance.

The performance is about what we could hope for, given the 9600 bps
rate of the serial connection.

The Convergent S/80 is a 16.67 MHz 68020 with 2MB memory, SCSI bus, 8
RS-232 ports and one printer port on a single board.  The ethernet
controller for the S/80 is a daughterboard which is a SCSI device.
The NFS and SLIP implementations are pretty good and are fairly easy
to configure, once you've read the documentation.

We also experimented with NFS over dial-up SLIP.  We were trying with
Telebit TB1000, though, and performance was not good.  It could be
done, but "dumb", fast modems are required to get any kind of
performance.

/craig

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