Can a hub diturb net boot process?

Hi,

I have a diskless Linux/X terminal that I boot from a machine on
the same segment, however my new hub seems to break the entire boot
process.

With the old dumb 10Mbs hub everything seems to work fine - DHCP
license is obtained, the boot image is transferred and NFS mounts
without problem - the no delays, no glitches.

When I replace the old hub with a new one - SMC EZSwitch 10/100
there are pauses in the boot image transfer, the NFS times out /
resumes endlessly and boot-up freezes or if completes the computer
is very slow.

My new hub is caching and it memorizes MAC addresses - so I have to
switch it off/on if I change a network card and I do that. Other
computers on the same ring work pretty well. I am able to make NFS
mounts on the same partitions from another computers, but not from
the diskless one.

The problem does not seem to be either in the network card - I
tried two - 3C509 (10Mb) and Dfe538 (100mb), same result.

So, someone having a suggestion why a hub may break a diskless
boot?

Thanks, George.

G. Georgiev <noone@nowhere.com> wrote:

> My new hub is caching and it memorizes MAC addresses - so I have to
> switch it off/on if I change a network card and I do that.

Your "hub" would in fact appear to be a switch.

> Other computers on the same ring work pretty well. I am able to make
> NFS mounts on the same partitions from another computers, but not from
> the diskless one.

It is quite possible that there is an incompatibility in the MDI
autonegotiation in the switch/hub and the network card in either the
diskless server or the client.

Try turning off MDI autonogiation on the diskless server by forcing it
to a particular media-type (using mii-tool), or use a different NIC.

--
Cameron Kerr
cameron.kerr@paradise.net.nz : http://nzgeeks.org/cameron/
Empowered by Perl!

On Thu, 20 May 2004 22:15:18 -0400, G. Georgiev <noone@nowhere.com> wrote:
> Hi,
>
> I have a diskless Linux/X terminal that I boot from a machine on
> the same segment, however my new hub seems to break the entire boot
> process.
>
> With the old dumb 10Mbs hub everything seems to work fine - DHCP
> license is obtained, the boot image is transferred and NFS mounts
> without problem - the no delays, no glitches.
>
> When I replace the old hub with a new one - SMC EZSwitch 10/100
> there are pauses in the boot image transfer, the NFS times out /
> resumes endlessly and boot-up freezes or if completes the computer
> is very slow.
>
> My new hub is caching and it memorizes MAC addresses - so I have to
> switch it off/on if I change a network card and I do that. Other
> computers on the same ring work pretty well. I am able to make NFS
> mounts on the same partitions from another computers, but not from
> the diskless one.
>
> The problem does not seem to be either in the network card - I
> tried two - 3C509 (10Mb) and Dfe538 (100mb), same result.

Not sure if it is an issue, but I have had trouble getting 10/100 PC Cards
(16-bit and cardbus) to negotiate link speed with switch ports on an SMC
broadband router, unless the nics were set to 10baseT (full duplex at that
speed worked). Although, never had trouble with 10/100 PCI nics on it.

I have also had trouble with older 8139too (before it supported mii-tool)
going off in a frenzy (constant flickering link LED) unless other end was
dropped back to 10baseT, but just occassionally (when I notice heavy
packet loss). Newer 8139too works with mii-tool.

Make sure the cable you are using to the switch is a standard patch cable,
and not to uplink port (or uplink switch in wrong position). Although, if
it has no uplink port or switch, it may be an auto sensing switch, so
cable type would not matter.

--
David Efflandt - All spam ignored http://www.de-srv.com/