SUMMARY: Slow tftp during booting a diskless SUN 3/50 because of ROM revision

From: V.Sander (
Date: Mon Jan 24 1994 - 20:47:51 CST

Hallo SUN managers,

my original question was:

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Hallo SUN Managers,

we are using some 3/50 with Xkernel and it works fine.
Migrating the boot-server to SPARC (SS 10 4.1.3) we run into a problem.

The 3/50 with ROM revision 2.8 boots fine, boot those 3/50 with revision
2.7 took about 15 minutes to tftp the boot image from the SS10. Thereafter
the boot process is as usual.

Any suggestions on how to speed up the tftp?

Many thanks,
Volker Sander

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I received only one response. Ron Vasey writes:

   I think your problem could be with the difference in the speeds of the two
   ethernet interfaces rather than with tftp. I once had a similar problem
   booting unix when the server and client speeds differed considerably
   (3/50 from ELC, SLC from 3/160, etc.). I didn't run extensive tests
   but strongly suspected that the fast systems would respond quicker than
   the slower ones could recover. Such disparity can cause real problems
   with UDP-based protocols such as tftp, which do not sequence the packets
   and work best among similar-performing peers. There was never a problem
   with TCP-based connections (although I didn't check the retries, either!).
   My solution was to boot clients from comparable servers (Sun3s from Sun3s).

I turned the udp_checksumming flag on, to reduce the speed of the server.
But this didn't help. Because we do not use any further SUN3, we still have
the problem of slow tftp performance.

Many thanks Ron!!!!!!


    Volker Sander
    Central Institute for Applied Mathematics
    Research Center Juelich
    52425 Juelich

    Phone: (+49) 2461 / 61- 6586

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