What does Router Advertisement do?

Hi,
I have HE tunnel working on my VPS. I'm setting up VPN for my own use and to enlarge knowledge about ipv6. I have pptp tunnel. On server side ppp0 has fe80::1 link-local address and client has fe80::2. If I start radvd with config below:

Code:

interface ppp0
{
   IgnoreIfMissing on;
   AdvSendAdvert on;
   MaxRtrAdvInterval 60;
   AdvLinkMTU 1396;
   prefix 2001:470:xxxx:dead::/64
   {
   AdvOnLink on;
   AdvAutonomous on;
   };
};

I have to set route for client ip on server (eg ip -6 route add 2001:470:xxxx:dead::2 dev ppp0) and everything works fine. I tried to set routing and addresses on client (windows 7) side manually (identically), without RA. Tcpdump on server doesn't show any icmpv6 packet. I have to set address source to fe80::2 in order to capture any packets. Beside adding route and setting address, what else does RA do? I noticed also, that "netsh int ipv6 show neighbors" shows fe80::1 as router:

Code:

netsh interface ipv6>show neigh vpn

Interfejs 38: VPN

Address physical address Type
-------------------------------------------- ----------------- -----------
2001:470:xxxx:dead::20 Stałe
fe80::1 Stałe (Router)
ff02::2 Stałe
ff02::c Stałe
ff02::16 Stałe
ff02::1:2 Stałe
ff02::1:3 Stałe
ff02::1:ff00:2 Stałe
ff02::1:ff00:20 Stałe

Stałe means persistent. I see no option to set that manually. I want to understand this better, because I want to replace radvd with dibbler-server. If i start dibbler IP is assigned, DNS servers also, but I have no connection. Any help will be highly appreciated.

//Edit:
OK, I noticed that I can capture packets if host address part is same as in link-local address, but I don't know is this from IPv6 spec. or specified for MS OSes

Kind regards,
Matthew Pałosz