OSPF(Open Shortest Path First) Routing protocol configuration on Packet Tracer

OSPF

  • Link State Protocol
  • Open Standard
  • Successor of RIP
  • Uses Dijkstra(shortest Path first(SPF) algorithm)
  • Classless routing protocol
  • Updates are sent through multicast IP address 224.0.0.5
  • Triggered updates & periodic updates
  • Hello packets are sent every 10 secs
  • Dead time is 40 secs
  • Administrative distance is 110
  • Metric= cost =10^8/ Bandwidth in bps(CISCO)
  • Unlimited hop count
  • Faster Convergence
  • Hierarchical design with multiple areas
  • One area has to be designated as Area 0
  • Area 0(zero) is called the backbone area

    Neighbor

    1.  Routers that share a common link become neighbors
    2. Neighbors are discovered by hello packets
    3. To become neighbors the following should match
    • Area ID
    • Hello and dead intervals
    • Authentication

    Adjacency

    1. Adjacencies are formed once neighbor relation is established
    2. In Adjacencies the database details are exchanged

    OSPF TABLES

    Neighbor Table: 

    It contains directly connected routers information

    Database Table: 

    It contains complete topology of the network

    Routing Table: 

    It contains directly connected networks and best path information is available, which gets from database table.

    Wildcard mask= Global Subnet mask-Customized subnet mask

    Eg: 255.255.255.255                                     255.255.255.255
          255.255.255.0                                         255.255.255.240
       ------------------------       OR                              -----------------------------
           0.0.0.255                                                   0.0.0.15
    ---------------------------                                       ------------------------------


    Syntax
    Router(Config)#Router OSPF <pid>(process id 1-65535)
    Router(Config-Router)#Network <Network id> <wildcard mask> area <area no>(any numbers)


    Verification commands
    Router#show ip ospf neighbor
    To check the neighbor table.

    Router#show ip ospf database
    To check the database table.
Video is available on below link
http://youtu.be/zodPkApSvTI

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