AW: STP vs. DHCP during Debian pxeboot installs

Dirk Heindel Dirk.Heindel at
Mon Sep 28 09:48:23 CDT 2009


enabling Port-Fast Mode on the switch ports could be a solution for this problem too.
It will not block the port until a loop is detected.
Without Port-Fast, STP will block a port until no loop is detected.

Dirk Heindel

-----Ursprüngliche Nachricht-----
Von: linux-poweredge-bounces at [mailto:linux-poweredge-bounces at] Im Auftrag von Jim Freeman
Gesendet: Freitag, 18. September 2009 19:45
An: debian-boot at; linux-poweredge at
Betreff: STP vs. DHCP during Debian pxeboot installs


When performing unattended Debian installations across a network, some
switch protocols/configurations thwart required DHCP negotiation by
simply blocking traffic for a time, and DHCP gives up after its default
timeout period.

For instance, in installing some Dell M610 blades (Broadcom NetXtreme II
adapters - bnx2 linux driver module) within Cisco switch fabric running
STP (Spanning Tree Protocol), interface traffic is blocked until STP can
determine that the port coming on-line does not introduce any switching
loops.  The DHCP requests being sent during that time just fall on the
floor, and DHCP gives up before it's ever really given a chance.


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