[Dibbler] Issue with short lifetimes

Karl Auer kauer at biplane.com.au
Sat May 22 10:47:53 CEST 2010


Hullo there.

This has perhaps been discussed before; my apologies if so.

I was using the Dibbler server and Dibbler client recently while
presenting a course. To demonstrate what happened with renewals, I
configured the server to issue very short lifetimes (30 seconds
preferred, 40 seconds valid). The client obtained an address OK, but 40
seconds later the address disappeared from the client interface! The
client was still running, but a packet trace showed that no attempt had
been made to by the client renew the address.

Reading the documentation, I realised that the default preferred and
valid lifetimes are *fixed*. Because I was not setting the T1 and T2
parameters in the server, the client was not renewing until far, far too
late.

Can I suggest that the default lifetimes used by the client be some
suitable proportion of the received preferred lifetimes? For example,
T1=0.5x the preferred lifetime and T2=0.75x? These would only be used if
not overridden by specified lifetimes of course.

This is with Dibbler version 0.7.1, as distributed in the Ubuntu 9.04
distro.

Thanks for Dibbler, and best regards, K.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Karl Auer (kauer at biplane.com.au)                   +61-2-64957160 (h)
http://www.biplane.com.au/~kauer/                  +61-428-957160 (mob)

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