OSPF(Open Shortest Path First) Dynamic Routing

   OSPF DYNAMIC ROUTING :

1. ospf stand for open shortest path first. and it is  layer 3 protocal.

2. Open Shortest Path First (OSPF) is an open standards routing protocol that’s been implemented by a wide variety of network vendors, including Cisco.

3. OSPF converges quickly, although perhaps not as quickly as EIGRP, and it supports multiple, equal-cost routes to the same destination. 

 4.Administrative distance (AD) value is 110 and protocol no . is 89.

5. It use dijkstra algorithum to find best path.

6. Ospf supposed to be designed in a hierachical fashion, which basically means that you can separate the larger iinternetworks into

 smaller      internetwork called areas.

7. OSPF support only ip networks.

8. OSPF send routing table with unicaste /multicast with the 224.0.0.5 and 224.0.0.6  .

9. OSPF used process id (1- 65535) always effect locally not globally.

10. it is classless routing and support VLSM.And used wild-card mask (inverse of subnett mask).


OSPF CONFIGURATION: 

STEP 1.  router ospf 2( it is a proccess id)
step2. network 1.0.0.0( network ip address)  0.255.255.255(wildcard-mask  ) area 10.
step 3 . do wr.
see in ass fig. 

                      

ospf confiquration

     here in the fig we used
10.0.0.0 in place of 2.0.0.0  .for loopback 0.
.

  OSPF TERMINOLOGY:

LINK: - A link is a network or router interface assigned to any given network.

ROUTER ID: - The router id is an IP address used to identify the router. CISCO chooses the router id by using the highest IP address of all configured loopback interface.

NEIGHBOR: - neighbors are two or more routers that have an interface on a common network, such as two routers connected on a point to point serial link.

 ADJANCECY: - An adjacency is a relationship between two OSPF routers that permit the direct exchange of route updates.

 Neighbor ship database: - The neighbor ship database is a list of all OSPF routers for which hello packet has been send.

 

Link state advertisement: - A link state advertisement (LSA) is an OSPF packet containing link state and routing information that’s shared among OSPF router.

 

                                                                                      OSPF AUTHENTICATION:

 

  There are three types of authentication support by ospf routing.

  1. Null Authentication.

  2. clear text Authentication .

 

            

clear text authentication

 

  3. MD5 Authentication.

 

                     

md5 authentication

 

 

NOTE :- this above fig code used for ospf authentication on interface.