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Webcast-Catalyst9k
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OSPF DR

Is this elected by the router with the lowest priority on an interface, I hear they are all set to default as 1, so in which case does it take the router with the highest active IP ?

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Re: OSPF DR

Carl,

""The OSPF interface priority is the parameter that controls DR election. Its default value is “1”. When OSPF interface priority is “0”, the router is not eligible to become a DR. If a router comes up on a network segment and there are no other routers there already, it will become a DR. If there is an existing DR (or BDR), the new router will NOT attempt to preempt them. If several routers come up at roughly the same time (or the DR fails), a new DR election process will be triggered. The router with the highest priority value then will become a DR.

If the priorities are the same, the router with the highest router ID becomes the DR

The OSPF router id is either manually created by using the ospf router-id command or generated automatically by follwing this process. Use the address of the loopback 0 interface if no loopback then use the highest IP address of any interface if no interface exists, set the router-ID to 0.0.0.0

Patrick

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