OSPF Protocol Basic Overview
What is OSPF
Language-wise it stands for Open Shortest Path First, and Family wise it belongs to the Link-State Interior Gateway Dynamic Routing Protocols.
done with the CV yet?, OSPF is an open standard internal routing protocol that is supported across all the different vendors manufacturing networking platforms.
In this article, we will review the basics and specs of this protocol, and see its own unique features.
OSPF Neighbor States
As a start, the OSPF routing protocol uses a multicast hello message that is destined to the OSPF Multicast address of 244.0.0.5 seeking any possible other OSPF routers in the area.
This message keeps repeating every 10 seconds by default, and that will be out of the interfaces that announced an OSPF configuration, which depends on how you configured it + the vendor-specific configuration template.
Upon receiving a multicast hello message from another router we already sent it a hello message earlier, and that should be within the dead timer of 40 seconds maximum (by default).
An OSPF neighbor process will start by:
-
Init:
- at the moment of confirmation that a bidirectional multicast hello has initiated
-
2-Way:
- communication from the 2 parts has successfully occurred
-
ExStart:
