CCNA 3 - Capitulo 2.5

CCNA 3 - Capitulo 2.5

1. SINGLE-AREA OSPFv4 CONFIGURATION

   • DEFAULT ROUTE PROPAGATION
     • WHATS IS AUTONOMOUS SYSTEM BOUNDARY ROUTER (ASBR) ?
       • ROUTER CONNECTED TO THE INTERNET
       • LOCATED BETWEEN AN OSPF ROUTING DOMAIN AND NON OSPF NETWORK
       • PROPAGATE DEFAULT STATIC ROUTE OTHERs OSPF ROUTERs
     • TO PROPAGATE A DEFAULT ROUTE , THE EDGE ROUTE (ASBR) MUST BE CONFIGURED THE FOLLOWING
       • DEFAULT ROUTE
         • R2#(CONFIG)IP ROUTE 0.0.0.0 0.0.0.0 next hop address exit interface
       • DEFAULT INFORMATION ORIGINATE
         • PROPAGATE THE DEFAULT STATIC ROUTE IN OSPF UPDATES
         • R2(CONFIG)#ROUTER OSPF 10
         • R2#(CONFIG) DEFAULT-INFORMATION ORIGINATE
     • HOW TO VERIFY ?
       • R2#SHOW IP ROUTE | BEGIN GATEWAY

2. VERIFY SINGLE AREA OSPFv2

   • VERIFY OSPF NEIGHBORS
     • R1#SHOW IP INTERFACE BRIEF
       • IP INTERFACE ARE ACTIVE AN CORRECT ADDRESSING
     • R1#SHOW IP ROUTE
       • VERIFIES THAT THE ROUTING TABLE CONTAINS ALL THE EXPECTED ROUTES
     • R1#SHOW IP OSPF NEIGHBOR
       • VERIFY THE ROUTER HAS FORMED ADJASCENCY NEIGHBORING ROUTERS
       • NEIGHBOR NOT DISPLAY OR DOES NOT SHOW STATE FULL ?
         • NOT FORMED ADJASCENCY
           • REASONS FOR THE NON-FORMATION OF ADJACENCY?
             • THE SUBNET MASKS DO NOT MATCH, CAUSING THE ROUTERS TO BE ON SEPARATE NETWORKS.
             • THE OSPFV2 HELLO OR DEAD TIMERS DO NOT MATCH.
             • THE OSPFV2 NETWORK TYPES DO NOT MATCH.
             • THERE IS A MISSING OR INCORRECT OSPFV2 NETWORK COMMAND.
       • DECIPHERING THE COMMAND
         • NEIGHBOR ID
           • ROUTER ID NEIGHBORING ROUTER
         • PRI
           • PRIORITY OF THE INTERFACE
           • USED DR AND DBR ELECTION
         • STATE
           • STATE OF INTERFACE
           • STATE FULL = ROUTER AND NEIGHBOR HAVE IDENTICAL LSDBs
         • DEAD TIME
           • THE VALUE IS RESET WHEN RECEIVES A HELLO PACKET
           • AMOUNT OF TIME REMAINING ROUTER WAITS TO RECEIVE AN OSPFv2 HELLO PACKET
         • ADDRESS
           • NEIGHBOR THIS ROUTER IS DIRECLY CONNECTEDt
         • INTERFACE
           • INTERFACE HAS FORMED ADJASCENCY WITH THE NEIGHBOR
   • VERIFY OSPF PROTOCOL SETTINGS
     • R1#SHOW IP PROTOCOLS
       • VERIFY OSPF CONFIGURATION INFORMATION
         • PASSIVE INTERFACE
   • VERIFY OSPF PROCESS INFORMATION
     • R1#SHOW IP OSPFk
     • OSPFv2 AREA INFORMATION , LAST TIME THE SPF ALGORITM WAS EXECUTED
   • VERIFY OSPF INTERFACE SETTINGS
     • R1#SHOW IP OSPF INTERFACE
       • DEFAILED LIST FOR EVERY OSPFv2 ENABLED INTERFACE
     • R1#SHOW IP OSPF INTERFACE BRIEF
       • QUICK SUMMARY OSPFv2 ENABLED INTERFACES
         • INTERFACES ARE PARTICIPATING IN OSPF
         • NETWORK THAT ARE BEING ADVERTISED
         • COST OS EACH LINK
         • NETWORK STATE
         • NUMBER OF NEIGHBORS ON EACH LINK