OSPF neighbor state progression, as defined in RFC 2328 and displayed by Junos through show ospf neighbor, moves through a well-defined set of named states: Down, Attempt, Init, 2-Way, ExStart, Exchange, Loading, and Full. Down is the initial state, indicating no Hello packets have been recently received from a potential neighbor on that interface; it is a genuine, valid OSPF state and is correctly included here. Init indicates that a Hello packet has been received from the neighbor, but that neighbor has not yet listed the local router's own router ID within its Hello packet, so bidirectional communication has not yet been confirmed; this too is a standard, valid state. Loading occurs after the Exchange state, during which Database Description packets have been fully exchanged and the router is now actively requesting the specific, more-detailed LSAs it identified as missing or outdated from its neighbor via Link State Request packets; it is likewise a standard, valid OSPF neighbor state. 'Established' is not an OSPF state at all — that terminology belongs to BGP's finite state machine, where Established represents the fully operational session state; the OSPF equivalent concept is instead called Full. 'Reject' is not a recognized OSPF neighbor state under any circumstance and does not appear anywhere in the RFC 2328 state machine, making it an invalid distractor as well. Reference topics: Junos Enterprise Routing – OSPF, The OSPF Neighbor State Machine.
Contribute your Thoughts:
Chosen Answer:
This is a voting comment (?). You can switch to a simple comment. It is better to Upvote an existing comment if you don't have anything to add.
Submit