Shulou(Shulou.com)06/01 Report--

One OSPF (Open shortest path first)

① is based on IP, port number 89, multicast, no loop mechanism.

② link-state routing protocol Huasan: AD 10 Cisco: AD 110

③ COST (link cost) = 10 ^ 8 / interface bandwidth

The narrower the bandwidth of ④, the greater the cost.

Bandwidth is inversely proportional to cost

⑤ default priority: internal 10 external 150 static 60

⑥ cares about cost and bandwidth

2. OSPF message type

① Hello establish and maintain ospf and neighbor relationship (establish and maintain)

② DBD link-state database description information (summary)

③ LSR link-state request, requesting link-state information from ospf neighbors (reply)

④ LSU link-state update (request)

⑤ LSAck confirms (acknowledges) the LSA in LSU

Three OSPF three tables

① neighbor table

② topology table (lsdb link-state database)

③ routing tabl

4. The working process of OSPF protocol

Find neighbors, establish neighbor relationships, pass link-state information, calculate routes

Five OSPF network types

① broadcast supports multiple access to broadcast

② peer-to-peer (P2P)

③ point to multipoint (P2MP)

④ NBMA

Six DR BDR

① DR Master (specified route)

② BDR backup (backup specified route)

Note: when ospf elects a route, the cost value does not affect the election DR/BDR, it only affects the routing algorithm.

Election DR BDR rule: the higher the priority of the ① interface, the more priority it will be selected as DR.

② if the priority is the same, the bigger the router-id, the better the priority.

③ if the router does not set router-id, then choose the IP address of the interface, the larger the priority.

Optimization of Seven OSPF

① HELLO time

② BFD

③ spf1-100

④ interface type

Eight OSPF regions

Backbone area, non-backbone area, special area.

Nine wildcard mask: the common name for anti-mask

Ten small experiments OSPF

R1

R1 (config) # int s 0Universe 1

R1 (config-if) # ip add 192.168.12.1 255.255.255.0

R1 (config-if) # no shu

R1 (config-if) # exi

R1 (config) # router ospf 1

R1 (config-router) # network 192.168.12.0 0.0.255 area 0

R1#show ip route

R1#show ip ospf neighbor

R2

R2 (config) # int s 0Universe 0

R2 (config-if) # ip add 192.168.12.2 255.255.255.0

R2 (config-if) # no shu

R2 (config-if) # int s 0Universe 1

R2 (config-if) # ip add 192.168.23.2 255.255.255.0

R2 (config-if) # no shu

R2 (config) # router ospf 1

R2 (config-router) # network 192.168.12.0 0.0.255 area 0

R2 (config-router) # network 192.168.23.0 0.0.0.255 area 0

R2 (config-router) # net

R2 (config-router) # network

R2#show ip route

R2#show ip ospf neighbor

R3

R3 (config) # int s 0lap 0

R3 (config-if) # ip add 192.168.23.3 255.255.255.0

R3 (config-if) # no shu

R3 (config) # router ospf 1

R3 (config-router) # network 192.168.23.0 0.0.0.255 area 0

R3#show ip route

R3#show ip ospf neighbor

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