1. What is OSPF
OSPF (the Open Shortest the Path First, Open Shortest Path First) is the IETF link-state interior autonomous system routing protocol
OSPF routing information propagates only the remote device does not have network convergence quickly and effectively avoid the waste of network resource
OSPF to work directly on the IP layer, IP protocol number 89
OSPF protocol packet to multicast addresses.
2, OSPF protocol work process has four main phases:
Looking neighbor adjacency establishment, link status information transmission, calculate routes
3, looking for neighbors
4, DR and BDR election
(1,) Hello packet includes priority router, router priority 0 does not have eligible to vote
(2) BDR first election, the election of the DR
(. 3,) the DR and BDR Once selected, even new higher priority router, OSPF DR and BDR in the area is not re-elected, only after DR and BDR fail, only to participate in elections
5, transmission of information (images from textbooks)
6, OSPF basic configuration command
A Router ID
[Router]router id router-id
Start OSPF process
[Router]ospf [ process-id ]
OSPF process restart
<Router>reset ospf [ process-id ] process
OSPF area
[Router-ospf-100]area area-id
Enable OSPF on the specified interface
[Router-ospf-1-area-0.0.0.0] network ip-address wildcard-mask
Configuring OSPF interface priority
[Router-Ethernet0/0] ospf dr-priority priority
Configuring OSPF Interface Cost
[Router-Ethernet0/0] ospf cost value