[radvd-devel-l] Default values of AdvValidLifetime and AdvPreferredLifetime

Pekka Savola pekkas at netcore.fi
Mon Feb 1 04:02:13 EST 2010

On Mon, 1 Feb 2010, Jiri Skala wrote:
> I have a question to implementation of following default values:
>                     RFC4861   RADVD
>                     RFC2461
> AdvValidLifetime     2592000   86400
> AdvPreferredLifetime  604800   14400
> Why differ these values against RFC? I'm asking due to a bug in BZ.

The reason is that if a host attaches to a LAN and soon afterwards 
leaves it, otherwise the autoconfigured addresses by default stay for 
a very long time.  This confuses people and more importantly, usually 
messes up default address selection so that the mobile device will try 
to use a wrong IP address.

Some more discussion here:

I think this is in most cases definitely a better choice 
operationally. If there's a standards compliancy concern wrt changing 
the default values, I can bring it up and ask opinions in the IETF.

Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

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