[syslinux] intermittent pxe failure

[Larry Howe]

Hi,

I have an intermittent pxelinux boot problem. It happens rarely, for example
it happened one day and then did not happen again until 6 days later. However
when it does happen it is rather serious as it affects all clients on the
network. Here is some basic info:

- IBM netvista PCs, built-in pxe, banner says it is "PXE 2.x".
- happens rarely, but when it does it affects all clients. May last for an
hour or so when it happens.
- DHCP - microsoft
- TFTP #1: hpa-tftp, started with -s /tftpboot -B 1468 -r blksize -v -v -v -v
- TFTP #2: winagents tftp server (tsize on, blksize negotiation off)
- network: WAN, but fiber-based and as fast as a LAN
- retrieving vmlinuz *always* works at all times (0 failures)
- retrieving initrd *almost always* works...except when this problem comes
 up, and then retrieving initrd *always* fails until some time passes and the
 problem goes away.

The error message is:

Loading vmlinuz.................
Could not find ramdisk image: initrd
boot:

We tried switching between TFTP #1 and TFTP #2, but no help there. In the
 tftp log, what we see is vmlinuz being transferred completely and normally,
 and then no further requests coming in.

I am using thinstation 2.2. I have also asked on that list but have not found
a solution. That thread can be found here:
http://www.nabble.com/intermittent-pxe-failure-t3655353.html

Question: what code is responsible for downloading vmlinuz, and which code is
responsible for downloading initrd? Is it the pxe firmware, or pxelinux
itself? What happens between the vmlinuz download and the initrd download?
Any network activity that could potentially lead to a failure? Is this
activity logged anywhere?

Any suggestions welcome!

Larry