Restoring Internet connection after router reboot

After I reboot my router I can no longer surf or connect to the internet straight away. Rebooting my pc fixes it as does just waiting a while (in XP at least - this doesn't seem to work on my w2000 machine).

What is it that changes, that stops the internet connecting after the router reboots, and is there a quicker way of dealing with it than the above?

 

first of all, why is the router rebooting?
now, if the mdm ever looses sync with the network(wan) due to outage, etc. the mdm typically aquires the network when service is restored. After mdm is back on the network, a lot of times you have to reset router.
what happens is if mdm ever looses connection to the net and then comes back on, the dhcp server will issue it an ip, however the mdm and router loose sync from each other, reason for reseting router so that the router can receive its ip address.
windows does have issues when trying to resynchronize with networks.