> From: Joakim Tjernlund <[email protected]>
> To: [email protected],
> Date: 2012/07/08 13:07
> Subject: [OSPF] OSPF Hello questions
> Sent by: [email protected]
>
>
> In RFC2328, last part of chapter 10.5 it reads:
>
> o Each Hello Packet causes the neighbor state machine to be
> executed with the event HelloReceived.
>
> o Then the list of neighbors contained in the Hello Packet is
> examined. If the router itself appears in this list, the
> neighbor state machine should be executed with the event 2-
> WayReceived. Otherwise, the neighbor state machine should
> be executed with the event 1-WayReceived, and the processing
> of the packet stops.
>
> o Next, if a change in the neighbor's Router Priority field
> was noted, the receiving interface's state machine is
> scheduled with the event NeighborChange.
>
> o If the neighbor is both declaring itself to be Designated
> Router (Hello Packet's Designated Router field = Neighbor IP
> address) and the Backup Designated Router field in the
> packet is equal to 0.0.0.0 and the receiving interface is in
> state Waiting, the receiving interface's state machine is
> scheduled with the event BackupSeen. Otherwise, if the
> neighbor is declaring itself to be Designated Router and it
> had not previously, or the neighbor is not declaring itself
> Designated Router where it had previously, the receiving
> interface's state machine is scheduled with the event
> NeighborChange.
>
> o If the neighbor is declaring itself to be Backup Designated
> Router (Hello Packet's Backup Designated Router field =
> Neighbor IP address) and the receiving interface is in state
> Waiting, the receiving interface's state machine is
> scheduled with the event BackupSeen. Otherwise, if the
> neighbor is declaring itself to be Backup Designated Router
> and it had not previously, or the neighbor is not declaring
> itself Backup Designated Router where it had previously, the
> receiving interface's state machine is scheduled with the
> event NeighborChange.
>
> Some questions:
> 1) Is it important that the above events are generated in this order? Is
> moving
> HelloReceived futher down allowed?
>
> 2) Following this list to the letter it seems that one could generate the
> same
> event several times. There could be 3 NeighborChange and 2 BackupSeen, is
> this
> the intentions or is it enough to generate each type at most once?
Follow up questions:
3) At what point should the hello options be saved into the internal
neighbor state?
4) When should prio, DR and BDR be saved? The text mentions saving these a
bit earlier but
it is unclear if this should be undone when hello pkg should be stopped(
see OneWayRecived for
and example).
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