[syslinux] gigabit networks and kernel loads

[H. Peter Anvin]

Mitchell E James wrote:
> I have been using pxelinux with Intel 850 1.7 Ghz P4 motherboards using
> 10/100 ethernet switches for about a year in a multichannel visual
> generation system.  We are shifting to SuperMicro P4SAA 2.8 Ghz P4
> motherboards with onboard gigabit ethernet and gigabit ethernet
> switches. Put are hung up because the diskless slave nodes will not load
> the (Linux) kernel from the master 2.8 Ghz computer.
> 
> Everything seems to be fine up to the kernel load.  The diskless node
> does a PXE boot and requests DHCP data from master. Pxelinux.0 loads and
> finds the configuration file. The menu comes up and the diskless node
> waits for time out.  After time out the diskless nodes start displaying
> messages about being unable to find bzImage.2.4.19 (the kernel file).
> My current belief at the moment is that this has something to do with
> packet handling being too slow/fast in pxelinux.

Sorry, that's most likely baloney.  TFTP is a lockstep protocol in part 
just to avoid having that kind of dependencies.

> Other observations:
> - Connecting a single diskless node to a master via one straight cable
> works fine.  The subnode boots every time.
> - Connecting a single diskless node to a master via a gigabit ethernet
> switch fails almost every time.

Sounds like there is a problem with the gigabit switch.  Perhaps your 
server has jumbo frames enabled and your switch doesn't handle them or 
doesn't have it enabled?

	-hpa