Re: [OSPF] Neighbour processing

[Joakim Tjernlund <joakim.tjernlund at transmode.se>]

Acee Lindem <acee.lindem at ericsson.com> wrote on 17/11/2009 14:36:10:
>
> Hi Joakim,
> If the inteface state is Waiting, then the BackupSeen event is scheduled. For
> more advanced interface states, the NeighborChange event is scheduled. You
> would never schedule both of them.
> Hope this Helps,

Yes it does, thanks.
Clarification though: "never schedule both of them" is that
per bullet?
If the first bullet schedules either a BackupSeen or NeighborChange should
the next bullet be skipped?

New question same chaper(10.5) there is:
        When receiving an Hello Packet from a neighbor on a broadcast,
        Point-to-MultiPoint or NBMA network, set the neighbor
        structure's Neighbor ID equal to the Router ID found in the
        packet's OSPF header.  For these network types, the neighbor
        structure's Router Priority field, Neighbor's Designated Router
        field, and Neighbor's Backup Designated Router field are also
        set equal to the corresponding fields found in the received
        Hello Packet; changes in these fields should be noted for
        possible use in the steps below.  When receiving an Hello on a
        point-to-point network (but not on a virtual link) set the
        neighbor structure's Neighbor IP address to the packet's IP
        source address.

I don't understand how virtual link fits. Should a Vlink
be considered to be in the same group as
"broadcast, Point-to-MultiPoint or NBMA network" or is
it its own group? If so what should be for vlinks?

  Jocke

> Acee
>
> |-----Original Message-----
> |From: ospf-bounces at ietf.org [mailto:ospf-bounces at ietf.org] On
> |Behalf Of Joakim Tjernlund
> |Sent: Tuesday, November 17, 2009 7:20 AM
> |To: ospf at ietf.org
> |Subject: [OSPF] Neighbour processing
> |
> |
> |I OSPF RFC 2328, chap 10.5 one can read:
> |        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.
> |
> |I wonder about the Otherwise, .. part in these two bullets:
> |Should this be read as iff the first part before the
> |"Otherwise, .." is false only the the otherwise part should be
> |performed? in other words, can each bullet generate a
> |BackupSeen AND NeighborChange or only one of them?
> |
> |Does the order matter, i.e is it valid to schedule two
> |BackupSeen then two NeighborChange?
> |Or should/must it be in order?
> |
> |           Jocke
> |
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