OSPF multi-region principle and configuration

Reasons for generating OSPF multi-region

1. Improve the scalability of the network

2. Fast Convergence

-----------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------

Capacity of the OSPF area

1. Intra-domain traffic

2. Inter-domain traffic

3. External traffic

------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------

Types of OSPF routers

1. Internal router

2. Regional border Router (ABR)

3. Self-made system border router (ASBR)

--------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------

Link status Advertisement

Type of LSA

1.LSA1: Router LSA, each router that runs the OSPF routing protocol generates router LSA advertisements.

The command show ip OSPF database router can view LSA information

The LSA of each router can be viewed by command show IP OSPF database router ID

2.LSA2: A specified router in a multi-fingered network generates a network LSA notification

The command show ip OSPF database network can be viewed

3.LSA3: The network rollup LSA, originating from the ABR router, sends the network summary LSA to an area that is used for the destination address outside the zone.

Through the command show ip OSPF database summary can be viewed

4.LSA4:ASBR Rollup LSA

By command show ip OSPF asbr-summary can view

5.LSA5: Autonomous System external LSA

The command show ip OSPF database external can view information about the as external LSA.

6.lsa6

------------------------------------------------------------------------------------------------------------

---------------------------------------------------------------------------------------------------------

Show IP route

Show IP route OSPF//view OSPF learning routes//

Show IP protocol//view OSPF protocol configuration information//

show ip OSPF//View how OSPF is configured on the router as well as the information of the ABR//

show ip OSPF database//View all LSA information within the LSDB//

Clear IP route

--------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------

Selection of Router routing entries

1. When the router receives a routing entry for the same destination address, first compare the administrative distance, and select a route entry with a small administrative distance to add to the routing entry. If the administrative distance is the same long as the comparison measure, select Small.

2. When the router receives the same destination address, administrative distance, and metrics, it forms a load balancer in the routing table.

Note that intra-domain routing is more priority than inter-domain routers.

--------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------

The administrative distance for static routes is 1 by default, and the measure is 0

The administrative distance of the RIP protocol is 120 by default and the metric is hop count

The OSPF protocol's administrative distance defaults to 110, and the measure is the cost of the interface.

---------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------

Configuration of the peripheral area

Everything else is just a command.

Area process number stub

Configuration of the complete peripheral area

Configure a command on the ABR inter-zone route

Area process number stub no-summary//Off ABR send Summary link advertises to complete peripheral region//

OSPF multi-region principle and configuration