The seventh day of studying in HCIA
6) The condition of becoming adjacency relationship-focus on network type
point-to-point: there can only be two nodes in a network-serial
MA (multiple access): there is no limit to the number of nodes in a network
if it is a point-to-point network Type, the neighbor relationship is directly established from the neighbor relationship.
If it is the MA network type, the DR/BDR role needs to be elected. In order to eliminate repeated updates,
all other routers
with no defined roles become DROther within 40s of election time . The adjacency relationship between DR and DROther is the adjacency relationship
between
DROther and DROther. The neighbor relationship between
DR and BDR is neighbor relationship
Election rules:
1. Interface priority The default interface priority of all routers is 1.
2. Compare the Router-ID with a higher priority
DR/BDR election is non-preemptive.
You can control the election by modifying the priority of the interface on which the device participates in the election.
[r2]interface GigabitEthernet 0/0/0
[r2-GigabitEthernet0/0/0]ospf dr-priority 5
<r2>reset ospf 1 process //Restart the OSPF process
Cannot change all interface priorities to 0
7) OSPF expanded configuration
1, default route - configured on the border router connected to carrier
[R1] OSPF 1
[R1-OSPF-1] // default-route-advertise non-forcible default
non-forcible Default: If you want to successfully deliver, there must be a default route in your routing table
[r1]ospf 1
[r1-ospf-1]default-route-advertise always //Forced to
deliver default 2, silent interface-only receive and not send OSPF packets. Generally used to connect to the user interface, forbidden to be used for the interface between routers
[r1]ospf 1
[r1-ospf-1]silent-interface GigabitEthernet 0/0/1