time lag between /sbin/ifconfig eth2 up and when interface becomes usable...

[Bruno Wolff III]

On Thu, Apr 10, 2008 at 13:39:36 -0400,
  Gautam Thaker <gthaker at atl.lmco.com> wrote:
> 
> From my tests it appears that it takes between 4 to 6 seconds after the 
> "up" command before my UDP packets actually start going out. The tests 
> are between two machines with addresses 192.168.0.2  <---> 192.168.0.3.
> 
> Any hints welcome. The "/sbin/ifconfig eth2 up 192.168.0.2" command 
> returns right away, but the interface is not ready to go for a few 
> seconds. What can this be due to?

It might be waiting for a test to see if any other machine is using that IP
address on that subnet. The time delay seems to be reasonable for a timeout
to a whohas arp request. Looking at the network traffic should allow you
to refute this or add some more suggestive evidence that this is the cause.