​​Summary:
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1. Configure all routers with basic IPs
2. Configure OSPF and make sure they all are in the backbone area and hardcode Router IDs sot they do not easily change
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1. Configure all routers to operate in the backbone area
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Belt(config-if)#do sh ip int br
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 10.1.1.2 YES manual up up
FastEthernet0/1 unassigned YES unset administratively down down
Serial1/0 unassigned YES unset administratively down down
Serial1/1 unassigned YES unset administratively down down
Serial1/2 unassigned YES unset administratively down down
Serial1/3 unassigned YES unset administratively down down
Belt(config-if)#
Tie(config-if)#do sh ip int br
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 10.1.1.1 YES manual up up
FastEthernet0/1 unassigned YES unset administratively down down
Serial1/0 unassigned YES unset administratively down down
Serial1/1 unassigned YES unset administratively down down
Serial1/2 unassigned YES unset administratively down down
Serial1/3 unassigned YES unset administratively down down
Tie(config-if)#
Sock(config-if)#do sh ip int br
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 10.1.1.3 YES manual up up
FastEthernet0/1 unassigned YES unset administratively down down
Serial1/0 10.1.2.1 YES manual up up
Serial1/1 unassigned YES unset administratively down down
Serial1/2 unassigned YES unset administratively down down
Serial1/3 unassigned YES unset administratively down down
Sock(config-if)#
Shoe(config-if)#do sh ip int br
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 10.1.3.1 YES manual up up
FastEthernet0/1 unassigned YES unset administratively down down
Serial1/0 10.1.2.2 YES manual up up
Serial1/1 unassigned YES unset administratively down down
Serial1/2 unassigned YES unset administratively down down
Serial1/3 unassigned YES unset administratively down down
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2. Configure OSPF and make sure they all are in the backbone area and hardcode Router IDs sot they do not easily change
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Shoe:
Shoe(config)#router ospf ?
<1-65535> Process ID
Shoe(config)#router ospf 1 !---------------------------------------------------------------1. config process ID
Shoe(config-router)#router-id 4.4.4.4 !-------------------------------------------------2. config router ID, has to be unique
Shoe(config-router)#network 10.1.2.2 0.0.0.0 area 0 !---- 3. network command: a. begins sending hello message out every
!-----identified interface; b. advertises the networks associated with
!-----every identified interface
Shoe(config-router)#network 10.1.3.1 0.0.0.0 area 0
sh ip protocols
sh ip ospf neighbor
sh ip route
Sock:
router ospf 1
router-id 3.3.3.3
network 10.1.2.1 0.0.0.0 area 0
network 10.1.1.0 0.0.0.255 area 0
sh ip protocols
sh ip ospf neighbor
sh ip route
Tie:
router ospf 1
router-id 1.1.1.1
network 10.1.1.1 0.0.0.0 area 0
sh ip ospf neighbor
Belt:
Belt#debug ip ospf adj
OSPF adjacency events debugging is on
Belt#
router ospf 1
router-id 2.2.2.2
router ospf 1
network 10.1.1.2 0.0.0.0 area 0
Belt(config-router)#
*Mar 1 01:06:00.703: OSPF: Interface FastEthernet0/0 going Up
*Mar 1 01:06:01.203: OSPF: Build router LSA for area 0, router ID 2.2.2.2, seq 0x80000001
*Mar 1 01:06:03.923: OSPF: 2 Way Communication to 3.3.3.3 on FastEthernet0/0, state 2WAY
*Mar 1 01:06:06.871: OSPF: 2 Way Communication to 1.1.1.1 on FastEthernet0/0, state 2WAY
*Mar 1 01:06:06.871: OSPF: Backup seen Event before WAIT timer on FastEthernet0/0
*Mar 1 01:06:06.875: OSPF: DR/BDR election on FastEthernet0/0
*Mar 1 01:06:06.875: OSPF: Elect BDR 1.1.1.1
*Mar 1 01:06:06.875: OSPF: Elect DR 3.3.3.3
*Mar 1 01:06:06.875: DR: 3.3.3.3 (Id) BDR: 1.1.1.1 (Id)
*Mar 1 01:06:06.875: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0xE9F opt 0x52 flag 0x7 len 32
*Mar 1 01:06:06.879: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0x208 opt 0x52 flag 0x7 len 32
*Mar 1 01:06:10.735: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0x532 opt 0x52 flag 0x7 len 32 mtu 1500 state EXSTART
*Mar 1 01:06:10.735: OSPF: First DBD and we are not SLAVE
*Mar 1 01:06:10.735: OSPF: Rcv DBD from 3.3.3.3 on FastEthernet0/0 seq 0xC64 opt 0x52 flag 0x7 len 32 mtu 1500 state EXSTART
*Mar 1 01:06:10.735: OSPF: NBR Negotiation Done. We are the SLAVE
*Mar 1 01:06:10.735: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0xC64 opt 0x52 flag 0x2 len 52
*Mar 1 01:06:10.747: OSPF: Rcv DBD from 3.3.3.3 on FastEthernet0/0 seq 0xC65 opt 0x52 flag 0x3 len 112 mtu 1500 state EXCHANGE
*Mar 1 01:06:10.747: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0xC65 opt 0x52 flag 0x0 len 32
*Mar 1 01:06:10.747: OSPF: Database request to 3.3.3.3
*Mar 1 01:06:10.747: OSPF: sent LS REQ packet to 10.1.1.3, length 48
*Mar 1 01:06:10.767: OSPF: Rcv DBD from 3.3.3.3 on FastEthernet0/0 seq 0xC66 opt 0x52 flag 0x1 len 32 mtu 1500 state EXCHANGE
*Mar 1 01:06:10.767: OSPF: Exchange Done with 3.3.3.3 on FastEthernet0/0
*Mar 1 01:06:10.767: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0xC66 opt 0x52 flag 0x0 len 32
*Mar 1 01:06:10.779: OSPF: Synchronized with 3.3.3.3 on FastEthernet0/0, state FULL
*Mar 1 01:06:10.779: %OSPF-5-ADJCHG: Process 1, Nbr 3.3.3.3 on FastEthernet0/0 from LOADING to FULL, Loading Done
*Mar 1 01:06:11.279: OSPF: Build router LSA for area 0, router ID 2.2.2.2, seq 0x80000002
*Mar 1 01:06:11.879: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0xE9F opt 0x52 flag 0x7 len 32
*Mar 1 01:06:11.879: OSPF: Retransmitting DBD to 1.1.1.1 on FastEthernet0/0 [1]
*Mar 1 01:06:11.911: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0xE9F opt 0x52 flag 0x2 len 132 mtu 1500 state EXSTART
*Mar 1 01:06:11.911: OSPF: NBR Negotiation Done. We are the MASTER
*Mar 1 01:06:11.911: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0xEA0 opt 0x52 flag 0x3 len 132
*Mar 1 01:06:11.911: OSPF: Database request to 1.1.1.1
*Mar 1 01:06:11.911: OSPF: sent LS REQ packet to 10.1.1.1, length 12
*Mar 1 01:06:11.931: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0xEA0 opt 0x52 flag 0x0 len 32 mtu 1500 state EXCHANGE
*Mar 1 01:06:11.931: OSPF: Send DBD to 1.1.1.1 on FastEthernet0/0 seq 0xEA1 opt 0x52 flag 0x1 len 32
*Mar 1 01:06:11.959: OSPF: Rcv DBD from 1.1.1.1 on FastEthernet0/0 seq 0xEA1 opt 0x52 flag 0x0 len 32 mtu 1500 state EXCHANGE
*Mar 1 01:06:11.959: OSPF: Exchange Done with 1.1.1.1 on FastEthernet0/0
*Mar 1 01:06:11.963: OSPF: Synchronized with 1.1.1.1 on FastEthernet0/0, state FULL
*Mar 1 01:06:11.963: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on FastEthernet0/0 from LOADING to FULL, Loading Done
Belt(config-router)#
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-Yu