Showing posts with label Neighbour Formation Stages in OSPF. Show all posts
Showing posts with label Neighbour Formation Stages in OSPF. Show all posts

Monday, June 29, 2015

Neighbour Formation Stages in OSPF

Previous post about OSPF... click here open-shortest-path-first.

Neighbour Formation Stages in OSPF



1. Down stage
It is attempt stage/ starting stage
        This is the first OSPF neighbour state. It means that no information (hellos) has been received from this neighbour, but hello packets can still be sent to the neighbour in this state.
2. Init
       This state specifies that the router has received a hello packet from its neighbour, but the receiving router's ID was not included in the hello packet. When a router receives a hello packet from a neighbour, it should list the sender's router ID in its hello packet as an acknowledgment that it received a valid hello packet.
3. 2-Way stage
       This state designates that bi-directional communication has been established between two routers. Bi-directional means that each router has seen the other's hello packet.
       At tilohe end of this stage, the DR and BDR for broadcast and non-broadcast multi-access networks are elected.