Protocols And Standards; Ospf Configuration Task List - HPE FlexNetwork HSR6800 Configuration Manual

Figure 20 DR and BDR in a network
DR
DR other
In OSPF, "neighbor" and "adjacency" are different concepts. After startup, OSPF sends a hello
packet on each OSPF interface. A receiving router checks parameters in the packet. If the
parameters match its own, the receiving router considers the sending router an OSPF neighbor. Two
OSPF neighbors establish an adjacency relationship after they synchronize their LSDBs through
exchange of DD packets and LSAs.
DR and BDR election
DR election is performed on broadcast or NBMA networks but not on P2P or P2MP networks.
Routers in a broadcast or NBMA network elect the DR and BDR by router priority and ID. Routers
with a router priority value higher than 0 are candidates for DR and BDR election.
The election votes are hello packets. Each router sends the DR elected by itself in a hello packet to
all the other routers. If two routers on the network declare themselves as the DR, the router with the
higher router priority wins. If router priorities are the same, the router with the higher router ID wins.
If a router with a higher router priority is added to the network after DR and BDR election, the router
cannot become the DR or BDR immediately because no DR election is performed for it. Therefore,
the DR of a network might not be the router with the highest priority, and the BDR might not be the
router with the second highest priority.

Protocols and standards

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RFC 1765, OSPF Database Overflow
•
RFC 2328, OSPF Version 2
•
RFC 3101, OSPF Not-So-Stubby Area (NSSA) Option
•
RFC 3137, OSPF Stub Router Advertisement
•
RFC 3630, Traffic Engineering Extensions to OSPF Version 2
•
RFC 4811, OSPF Out-of-Band LSDB Resynchronization
•
RFC 4812, OSPF Restart Signaling
•
RFC 4813, OSPF Link-Local Signaling

OSPF configuration task list

To run OSPF in a routing domain, you must first enable OSPF on the routers. Make a proper
configuration plan to avoid wrong settings that can result in route blocking and routing loops.
Complete the following tasks to configure OSPF:
BDR
DR other DR other
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