[OLSR-users] Re:Olsr Dhcp

Bernd Petrovitsch (spam-protected)
Mon Feb 27 11:12:13 CET 2006

On Mon, 2006-02-27 at 15:19 +0530, Vinay Menon wrote:
> Now in the above case Node1 assigned me the ip first.Then when i move
> over to Node2 i am not assigned an ip unless Node2 is restarted (no
> use restarting the pc).

Funny, that restarting Node2 helps.
The logic behind DHCP actually is:
- Client gets an IP address for the (so called) "lease time" and
  the server remembers this.
- Now the client can use that IP address for that time. Eventually
  (e.g. after half of the lease time) it tries to renew the lease
  (directly with the original DHCP server above) and either succeeds
  or starts from the initial DHCPDISCOVER where a new/another DHCP
  server could be chosen.
The client is allowed to store the lease information and simply use it
after e.g. reboot immediately. However, all DHCP clients that I know
(including Win*) allows you to explicitly release the old lease and
forcibly get a new one.
The conceptual situation (only for DHCP!) you have with your case is
that your PC moves from one "administrative domain" (read: from one
server) to a completely different one which may have completely
different administrative rules and technical parameters. Therefore an
automatic "switch over" (read: IP address renewal) is neither defined
and won't work in the general case.
It starts with the qeustion: When should that happen?
The only anwer in DHCP is "if the lease time is almost gone".

Perhaps you want to look into the "zeroconf" stuff (sorry, no URL and no
knowledge about that) which deals with plug-n-play IP configuration (as
if today someone may want that - I for sure not).

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