A router advertises its priority to become a designated router in its hello packets. On all multiaccess networks, the Hello protocol uses the advertised priorities to elect a designated router for the network. This router is responsible for sending network link advertisements, which describe all the routers attached to the network. These advertisements are flooded throughout a single area.
At least one router on each logical IP network or subnet must be eligible to be the designated router for OSPFv2. At least one router on each logical link must be eligible to be the designated router for OSPFv3.
A router’s priority for becoming the designated router is indicated by an arbitrary number from 0 through 255, with a higher value indicating a greater likelihood of becoming the designated router. By default, routers have a priority value of 128. A value of 1 means that the router has the least chance of becoming a designated router. A value of 0 marks the router as ineligible to become the designated router.
To modify the router’s priority value, include the priority statement:
- priority number;
For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.