Routing

Hello Experts,

Can some one please explain what exactly is the use of "dynamic-neighbors" option under ospf interface type p2mp? My understanding was with this option in Hub-and-Spoke scenarios , we can add new hops without any configuration chnages on Hub and the neighborship will for automatically.

But , I can see this happening even without specifying "dynamic-neighbors". Is there any other use of this option?

root@LAB# show protocols ospf   
area 0.0.0.0 {
    interface ge-0/0/1.0 {
        interface-type p2mp;
        dynamic-neighbors;
    }
}

Thanks,

Suraj

My understanding is that the dynamic-neighbors option is only needed when you are full mesh with all the sites on IPSEC VPN.  Not just in a hub and spoke setup. 

http://kb.juniper.net/InfoCenter/index?page=content&id=KB19521

Hi Steve,

Thansk for the reply. Dynamic-Neighbors is for interface type p2mp / point-to-multipoint or in other words HuB and Spoke. Even the KB you have referred states the below.

Enable point-to-multipoint and dynamic-neighbors for OSPF on st0:

set protocols ospf area 0.0.0.0 interface st0.0 interface-type p2mp
set protocols ospf area 0.0.0.0 interface st0.0 dynamic-neighbors

 

 

 

Also we cannot specify dynamic-neighbors until we make the interface p2mp.

 

I understand that.

But I believe it also only applies when you have the VPN configuration setup full mesh.  Where every site connects to every other site via the multipoint interface.

As opposed to hub and spoke where spoke sites only connect to the hub site.

this seems to overcome the duplicate path issue for neighbor relationships in OSPF