How to configure OSPF in Cisco IOS

Dynamic routing protocol OSPF routing protocol is probably the most popular . OSPF can be extended to larger networks , but also can be configured into small networks . While OSPF can be complicated to configure, its basic configuration is not so difficult . Below explained that since the OSPF configured on the Cisco operating system .
What you should know about OSPF ?

Before you configure OSPF , there are some things that you should consider . They are :

OSPF ( Open SHORTES Path First ) , uses the SPF algorithm to determine the best path to the destination .
OSPF routing protocol is standard . This means that OSPF can be configured in almost any router of different brands .
OSPF administrative distance is 110 .
Which operates OSPF Network called " Autonomous System " or " AS " .
All OSPF routing updates must pass through area 0 . For this reason , you need to design carefully before starting goalkeeper implementation of OSPF .
With OSPF , each router has topological map of the entire network . Routers use " Hello " packets to check if other routers are still at home. Each OSPF router identified in the " Router ID " . The router ID can be changed manually , otherwise the router will automatically select the IP address based on the greatest number .

What is OSPF features ?

OSPF offers the following features , which have also some other protocols :

Supports VLSM ( variable lenght subnet masks ) , which makes classless routing protocol
Support authentication of routing updates
Route redistribution of support from other routing protocols
OSPF works on point-to -point and point-to - multipoint , broadcast or non - broadcast settings
OSPF also offers some unique features such as Area stub , virtual links , etc. .
Since the OSPF configured in Cisco IOS ?

Run -in and specify the OSPF process ID . ID process itself may be awarded as desired . It is recommended that this number corresponds to the other routers in the configuration but is not necessary . Process ID number is not AS , although many people confuse .

Router ( config ) # router ospf process - ID { # }

Then , instruct the router to advertizoj ( advertise ) networks that are connected directly to the writing command :

Router ( config - router ) # network { XXXX YYYY } } { { z} area

In this example , network id XXXX is the network has directly connected to the router . Y.Y.Y.Y wildcard mask is that networks . Wildcard mask is the inverse form of subnet mask . Parameter " z" is the number of id 's area . For small networks , the parameter " z" can always configure the value to 0 , but for larger networks ( over 50 routers ) , areave IDs should be carefully planned .

In this way can advertizoni all networks you want , which are connected directly to the router where the configuration .

When you finish the configuration , the status could check through commands show ip route and show ip OSPF .

Examples of configuration

Below is an example of how to configure the routing protocol OSPF router :

Gigabit Ethernet interface 0 / 0
ip address 10.1.1.1 255.255.255.0

Serial interface 3 / 0
ip address 10.2.1.1 255.255.255.0

Router ( config ) # router ospf 1
Router ( config - router ) # network 10.1.1.1 0.0.0.255 area 0
Router ( config - router ) # network 10.2.1.1 0.0.0.255 area 0