Cisco Certified Network Associate (CCNA) Practice Exam

What is the default OSPF priority number for routers?

1. 0

2. 1

3. 2

4. 255

The correct answer is: 1

The default OSPF priority number for routers is 1. This priority value is used in the process of electing the designated router (DR) and backup designated router (BDR) in a broadcast network environment, such as an Ethernet segment. The designated router is responsible for reducing OSPF protocol traffic by acting as a central point for the exchange of routing information. If a router needs to be preferred as a designated router, the OSPF priority can be adjusted. A higher priority number increases the likelihood of a router becoming the DR, while a lower number reduces that chance. By default, if a router has a priority of 1, it is eligible to become the DR, but it is not guaranteed. A priority set to 0 will prevent the router from being elected as either a DR or BDR, while a priority of 255 indicates that the router should always be elected as the DR if it is operational. Thus, the establishment of a default priority of 1 allows routers to actively participate in the OSPF neighbor relationship and flow of information while still providing a basis for priority adjustments by network administrators.