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11-5 neighbor ip-address priority prioritySyntax Description:
Purpose: To influence the election of the DR. The router with the lowest non-zero priority will be elected the DR. In a hub and spoke topology, the hub router should be elected as the DR. Initial Cisco IOS Software Release: 10.0 Configuration Example: Setting the Priority of an OSPF NeighborConfigure the routers in Figure 11-8 as shown in the listing that follows . Figure 11-8. The Election of the DR Can Be Influenced by Using the priority Option with the neighbor Router Configuration Command
Router A interface Loopback0 ip address 1.1.1.1 255.255.255.255 ! interface Serial0/0 bandwidth 64 ip address 10.1.1.1 255.255.255.252 encapsulation frame-relay frame-relay map ip 10.1.1.2 101 broadcast no frame-relay inverse-arp frame-relay lmi-type ansi ! router ospf 1 network 1.1.1.1 0.0.0.0 area 1 network 10.1.1.0 0.0.0.3 area 0 ________________________________________________________________ Router B interface Loopback0 ip address 2.2.2.2 255.255.255.255 ! interface Serial0 ip address 10.1.1.2 255.255.255.252 encapsulation frame-relay bandwidth 64 frame-relay map ip 10.1.1.1 110 broadcast no frame-relay inverse-arp frame-relay lmi-type ansi ! router ospf 1 network 2.2.2.2 0.0.0.0 area 2 network 10.1.1.0 0.0.0.3 area 0 neighbor 10.1.1.1 priority 1 Examine the state of the OSPF neighbors to determine which router has been elected the DR. rtrA# show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 2.2.2.2 1 FULL/BDR 00:01:45 10.1.1.2 Serial0/0 ______________________________________________________________________________________________________________ rtrB# show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 1.1.1.1 1 FULL/DR 00:01:37 10.1.1.1 Serial0 Router A is the DR because it has a lower OSPF router ID. Modify the configuration on Router B so that it will be elected the DR. This can be accomplished by either setting the priority to 0 or larger than 1 in the neighbor statement. Router B router ospf 1 network 2.2.2.2 0.0.0.0 area 2 network 10.1.1.0 0.0.0.3 area 0 neighbor 10.1.1.1 priority 2 OSPF will not immediately elect a new DR. For stability reasons, OSPF will elect a new DR only if the current DR is down. Force the re-election of the DR by clearing the OSPF process on Router A. rtrA# clear ip ospf process Reset ALL OSPF processes? [no]: y rtrA# VerificationVerify that Router B has been elected as the DR. rtrA# show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 2.2.2.2 1 FULL/DR 00:01:45 10.1.1.2 Serial0/0 _____________________________________________________________________________________________________________ rtrB# show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 1.1.1.1 1 FULL/BDR 00:01:44 10.1.1.1 Serial0 Troubleshooting
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