2.7.1 Packet Tracer - Single-Area OSPFv2 Configuration (Answers)

2.7.1 Packet Tracer - Single-Area OSPFv2 Configuration Answers

Topology

2.7.1 Packet Tracer - Single-Area OSPFv2 Configuration

Addressing Table

Device	Interface	IP Address / Prefix
P2P-1	S0/1/0	10.0.0.1/30
	S0/1/1	10.0.0.9/30
	S0/2/0	10.0.0.13/30
P2P-2	S0/1/0	10.0.0.2/30
	S0/1/1	10.0.0.5/30
	G0/0/0	192.168.1.1/24
	G0/0/1	192.168.2.1/24
P2P-3	S0/1/0	10.0.0.6/30
	S0/1/1	10.0.0.10/30
	G0/0/0	192.168.3.1/28
BC-1	S0/1/0	10.0.0.14/30
	S0/1/1	64.0.100.2/30
	G0/0/0	10.0.1.1/29
BC-2	G0/0/0	192.168.4.1/24
BC-2	G0/0/1	10.0.1.2/29
BC-3	G0/0/0	192.168.5.1/24
BC-3	G0/0/1	10.0.1.3/29
Internet Server	NIC	203.0.113.100/24
PC 1	NIC	192.168.1.10/24
Laptop 1	NIC	192.168.2.20/24
Workgroup Server	NIC	192.168.3.14/28
PC 2	NIC	192.168.4.40/24
PC 3	NIC	192.168.5.50/24

Objectives

Implement single-area OSPFv2 in both point-to-point and broadcast multiaccess networks.

Background

You are helping a network engineer test an OSPF set up by building the network in the lab where you work. You have interconnected the devices and configured the interfaces and have connectivity within the local LANs. Your job is to complete the OSPF configuration according to the requirements left by the engineer.

Use the information provided and the list of requirements to configure the test network. When the task has been successfully completed, all hosts should be able to ping the internet server.

Instructions

Configure the network to meet the requirements.

Requirements

Use process ID 10 for OSPF activation on all routers.

Activate OSPF using network statements and inverse masks on the routers in the Headquarters network.

P2P-1(config)# router ospf 10
P2P-1(config-router)# network 10.0.0.0 0.0.0.3 area 0
P2P-1(config-router)# network 10.0.0.8 0.0.0.3 area 0
P2P-1(config-router)# network 10.0.0.12 0.0.0.3 area 0

P2P-2(config)# router ospf 10
P2P-2(config-router)# network 10.0.0.0 0.0.0.3 area 0
P2P-2(config-router)# network 10.0.0.4 0.0.0.3 area 0
P2P-2(config-router)# network 192.168.1.0 0.0.0.255 area 0
P2P-2(config-router)# network 192.168.2.0 0.0.0.255 area 0

P2P-3(config)# router ospf 10
P2P-3(config-router)# network 10.0.0.4 0.0.0.3 area 0
P2P-3(config-router)# network 10.0.0.8 0.0.0.3 area 0
P2P-3(config-router)# network 192.168.3.0 0.0.0.15 area 0

Activate OSPF by configuring the interfaces of the network devices in the Data Service network, where required.

BC-1(config)# interface gigabitethernet 0/0/0
BC-1(config-if)# ip ospf 10 area 0
BC-1(config-if)# interface serial 0/1/0
BC-1(config-if)# ip ospf 10 area 0

BC-2(config)# interface gigabitethernet 0/0/0
BC-2(config-if)# ip ospf 10 area 0
BC-2(config-if)# interface gigabitethernet 0/0/1
BC-2(config-if)# ip ospf 10 area 0

BC-3(config)# interface gigabitethernet 0/0/0
BC-3(config-if)# ip ospf 10 area 0
BC-3(config-if)# interface gigabitethernet 0/0/1
BC-3(config-if)# ip ospf 10 area 0

Configure router IDs on the multiaccess network routers as follows:

BC-1: 6.6.6.6
BC-2: 5.5.5.5
BC-3: 4.4.4.4

BC-1(config)# router ospf 10
BC-1(config-router)# router-id 6.6.6.6

BC-2(config)# router ospf 10
BC-2(config-router)# router-id 5.5.5.5

BC-3(config)# router ospf 10
BC-3(config-router)# router-id 4.4.4.4

Configure OSPF so that routing updates are not sent into networks where they are not required.

P2P-2(config)# router ospf 10
P2P-2(config-router)# passive-interface gigabitethernet 0/0/0
P2P-2(config-router)# passive-interface gigabitethernet 0/0/1

P2P-3(config)# router ospf 10
P2P-3(config-router)# passive-interface gigabitethernet 0/0/0

BC-1(config)# router ospf 10
BC-1(config-router)# passive-interface serial 0/1/1

BC-2(config)# router ospf 10
BC-2(config-router)# passive-interface gigabitethernet 0/0/0

BC-3(config)# router ospf 10
BC-3(config-router)# passive-interface gigabitethernet 0/0/0

Configure router BC-1 with the highest OSPF interface priority so that it will always be the designated router of the multiaccess network.
```
BC-1(config)# interface gigabitethernet 0/0/0
BC-1(config-if)# ip ospf priority 255
```
Configure a default route to the ISP cloud using the exit interface command argument.
```
BC-1(config)# ip route 0.0.0.0 0.0.0.0 Serial0/1/1
```

Automatically distribute the default route to all routers in the network.

BC-1(config)# router ospf 10
BC-1(config-router)# default-information originate

Configure the OSPF routers so that the Gigabit Ethernet interface cost will be 1 and the Fast Ethernet cost will be 10.
Formula: cost = reference-bandwidth (Mbps) / interface bandwidth (Mbps)

To make the Gigabit Ethernet interface cost equal to 1, the reference-bandwidth must equal the Gigabit Ethernet bandwidth itself, since any value divided by itself equals 1:

reference-bandwidth / 1000 = 1 → reference-bandwidth = 1000

Checking this value against the Fast Ethernet interface (100 Mbps) confirms it also satisfies the required cost of 10:

1000 / 100 = 10

Therefore, setting auto-cost reference-bandwidth 1000 simultaneously produces a Gigabit Ethernet cost of 1 and a Fast Ethernet cost of 10, matching both requirements at once.
```
P2P-1(config)# router ospf 10
P2P-1(config-router)# auto-cost reference-bandwidth 1000
```
```
P2P-2(config)# router ospf 10
P2P-2(config-router)# auto-cost reference-bandwidth 1000
```
```
P2P-3(config)# router ospf 10
P2P-3(config-router)# auto-cost reference-bandwidth 1000
```
```
BC-1(config)# router ospf 10
BC-1(config-router)# auto-cost reference-bandwidth 1000
```
```
BC-2(config)# router ospf 10
BC-2(config-router)# auto-cost reference-bandwidth 1000
```
```
BC-3(config)# router ospf 10
BC-3(config-router)# auto-cost reference-bandwidth 1000
```

Configure the OSPF cost value of P2P-1 interface Serial0/1/1 to 50.

P2P-1(config)# interface serial 0/1/1
P2P-1(config-if)# ip ospf cost 50

Configure the hello and dead timer values on the interfaces that connect P2P-1 and BC-1 to be twice the default values.

P2P-1(config)# interface serial 0/2/0
P2P-1(config-if)# ip ospf hello-interval 20
P2P-1(config-if)# ip ospf dead-interval 80

BC-1(config)# interface serial 0/1/0
BC-1(config-if)# ip ospf hello-interval 20
BC-1(config-if)# ip ospf dead-interval 80

Device Configs - Final

ROUTER P2P-1

! ==============================================================
!--- 2.7.1 Packet Tracer - Single-Area OSPFv2 Configuration
!--- ANSWER SCRIPT FOR ROUTER P2P-1
!--- Usage: open the P2P-1 CLI and paste this whole file at the P2P-1> prompt. Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Requirements: Use process ID 10 for OSPF activation on all routers.
! --------------------------------------------------------------

!--- Headquarters: activate OSPF with network statements and inverse masks.
router ospf 10
 network 10.0.0.0 0.0.0.3 area 0
 network 10.0.0.8 0.0.0.3 area 0
 network 10.0.0.12 0.0.0.3 area 0
 exit

!--- Reference bandwidth 1000 Mbps: GigabitEthernet cost 1, FastEthernet cost 10.
router ospf 10
 auto-cost reference-bandwidth 1000
 exit

!--- OSPF cost of Serial0/1/1 set to 50.
interface serial 0/1/1
 ip ospf cost 50
 exit

!--- Hello and dead timers on the link to BC-1 set to twice the defaults (20/80).
interface serial 0/2/0
 ip ospf hello-interval 20
 ip ospf dead-interval 80
 exit

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip protocols                    -> process 10, reference bandwidth 1000, the networks listed above
!---   show ip ospf neighbor                -> FULL adjacencies on the serial links
!---   show ip ospf interface serial 0/1/1  -> Cost: 50
!---   show ip ospf interface serial 0/2/0  -> Hello 20, Dead 80 (FULL with BC-1 after BC-1 uses the same timers)
!---   show ip route ospf                   -> O*E2 0.0.0.0/0 learned from BC-1
! ==============================================================

ROUTER P2P-2

! ==============================================================
!--- 2.7.1 Packet Tracer - Single-Area OSPFv2 Configuration
!--- ANSWER SCRIPT FOR ROUTER P2P-2
!--- Usage: open the P2P-2 CLI and paste this whole file at the P2P-2> prompt. Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Requirements: Use process ID 10 for OSPF activation on all routers.
! --------------------------------------------------------------

!--- Headquarters: activate OSPF with network statements and inverse masks.
router ospf 10
 network 10.0.0.0 0.0.0.3 area 0
 network 10.0.0.4 0.0.0.3 area 0
 network 192.168.1.0 0.0.0.255 area 0
 network 192.168.2.0 0.0.0.255 area 0
 exit

!--- Do not send routing updates into the LANs.
router ospf 10
 passive-interface gigabitethernet 0/0/0
 passive-interface gigabitethernet 0/0/1
 exit

!--- Reference bandwidth 1000 Mbps: GigabitEthernet cost 1, FastEthernet cost 10.
router ospf 10
 auto-cost reference-bandwidth 1000
 exit

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip protocols                             -> process 10, reference bandwidth 1000, the networks listed above
!---   show ip ospf neighbor                         -> FULL adjacencies on the serial links
!---   show ip ospf interface gigabitethernet 0/0/0  -> Cost: 1, No Hellos (Passive interface)
!---   show ip route ospf                            -> O*E2 0.0.0.0/0 learned from BC-1
! ==============================================================

ROUTER P2P-3

! ==============================================================
!--- 2.7.1 Packet Tracer - Single-Area OSPFv2 Configuration
!--- ANSWER SCRIPT FOR ROUTER P2P-3
!--- Usage: open the P2P-3 CLI and paste this whole file at the P2P-3> prompt. Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Requirements: Use process ID 10 for OSPF activation on all routers.
! --------------------------------------------------------------

!--- Headquarters: activate OSPF with network statements and inverse masks.
router ospf 10
 network 10.0.0.4 0.0.0.3 area 0
 network 10.0.0.8 0.0.0.3 area 0
 network 192.168.3.0 0.0.0.15 area 0
 exit

!--- Do not send routing updates into the LANs.
router ospf 10
 passive-interface gigabitethernet 0/0/0
 exit

!--- Reference bandwidth 1000 Mbps: GigabitEthernet cost 1, FastEthernet cost 10.
router ospf 10
 auto-cost reference-bandwidth 1000
 exit

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip protocols                             -> process 10, reference bandwidth 1000, the networks listed above
!---   show ip ospf neighbor                         -> FULL adjacencies on the serial links
!---   show ip ospf interface gigabitethernet 0/0/0  -> Cost: 1, No Hellos (Passive interface)
!---   show ip route ospf                            -> O*E2 0.0.0.0/0 learned from BC-1
! ==============================================================

ROUTER BC-1

! ==============================================================
!--- 2.7.1 Packet Tracer - Single-Area OSPFv2 Configuration
!--- ANSWER SCRIPT FOR ROUTER BC-1
!--- Usage: open the BC-1 CLI and paste this whole file at the BC-1> prompt. Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Requirements: Use process ID 10 for OSPF activation on all routers.
! --------------------------------------------------------------

!--- Router ID 6.6.6.6 (set before OSPF starts on the interfaces).
router ospf 10
 router-id 6.6.6.6
 exit

!--- Highest OSPF priority on G0/0/0 so BC-1 is always the DR of the multiaccess network.
interface gigabitethernet 0/0/0
 ip ospf priority 255
 exit

!--- Data Services: activate OSPF on G0/0/0.
interface gigabitethernet 0/0/0
 ip ospf 10 area 0
 exit

!--- Data Services: activate OSPF on S0/1/0.
interface serial 0/1/0
 ip ospf 10 area 0
 exit

!--- Do not send routing updates where they are not required.
router ospf 10
 passive-interface serial 0/1/1
 exit

!--- Default route to the ISP cloud using the exit interface.
ip route 0.0.0.0 0.0.0.0 Serial0/1/1

!--- Automatically distribute the default route to all OSPF routers.
router ospf 10
 default-information originate
 exit

!--- Reference bandwidth 1000 Mbps: GigabitEthernet cost 1, FastEthernet cost 10.
router ospf 10
 auto-cost reference-bandwidth 1000
 exit

!--- Hello and dead timers on the link to P2P-1 set to twice the defaults (20/80).
interface serial 0/1/0
 ip ospf hello-interval 20
 ip ospf dead-interval 80
 exit

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip ospf interface gigabitethernet 0/0/0  -> State DR, Priority 255, Cost 1
!---   show ip ospf neighbor                         -> P2P-1 FULL on Serial0/1/0, BC-2 FULL/BDR and BC-3 FULL/DROTHER on G0/0/0
!---   show ip route                                 -> Gateway of last resort, S* 0.0.0.0/0 via Serial0/1/1
!--- Note: paste this script on BC-1 before BC-2 and BC-3, so BC-1 wins the DR election (the election
!--- is not preemptive). The P2P-1 adjacency comes up after both ends use hello 20 / dead 80.
! ==============================================================

ROUTER BC-2

! ==============================================================
!--- 2.7.1 Packet Tracer - Single-Area OSPFv2 Configuration
!--- ANSWER SCRIPT FOR ROUTER BC-2
!--- Usage: open the BC-2 CLI and paste this whole file at the BC-2> prompt. Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Requirements: Use process ID 10 for OSPF activation on all routers.
! --------------------------------------------------------------

!--- Router ID 5.5.5.5 (set before OSPF starts on the interfaces).
router ospf 10
 router-id 5.5.5.5
 exit

!--- Data Services: activate OSPF on G0/0/0.
interface gigabitethernet 0/0/0
 ip ospf 10 area 0
 exit

!--- Data Services: activate OSPF on G0/0/1.
interface gigabitethernet 0/0/1
 ip ospf 10 area 0
 exit

!--- Do not send routing updates into the LAN.
router ospf 10
 passive-interface gigabitethernet 0/0/0
 exit

!--- Reference bandwidth 1000 Mbps: GigabitEthernet cost 1, FastEthernet cost 10.
router ospf 10
 auto-cost reference-bandwidth 1000
 exit

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip protocols      -> router ID 5.5.5.5, GigabitEthernet0/0/0 passive
!---   show ip ospf neighbor  -> BC-1 (6.6.6.6) FULL/DR, BC-3 (4.4.4.4) FULL/DROTHER; BC-2 is the BDR
!---   show ip route ospf     -> O*E2 0.0.0.0/0 learned from BC-1
! ==============================================================

ROUTER BC-3

! ==============================================================
!--- 2.7.1 Packet Tracer - Single-Area OSPFv2 Configuration
!--- ANSWER SCRIPT FOR ROUTER BC-3
!--- Usage: open the BC-3 CLI and paste this whole file at the BC-3> prompt. Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Requirements: Use process ID 10 for OSPF activation on all routers.
! --------------------------------------------------------------

!--- Router ID 4.4.4.4 (set before OSPF starts on the interfaces).
router ospf 10
 router-id 4.4.4.4
 exit

!--- Data Services: activate OSPF on G0/0/0.
interface gigabitethernet 0/0/0
 ip ospf 10 area 0
 exit

!--- Data Services: activate OSPF on G0/0/1.
interface gigabitethernet 0/0/1
 ip ospf 10 area 0
 exit

!--- Do not send routing updates into the LAN.
router ospf 10
 passive-interface gigabitethernet 0/0/0
 exit

!--- Reference bandwidth 1000 Mbps: GigabitEthernet cost 1, FastEthernet cost 10.
router ospf 10
 auto-cost reference-bandwidth 1000
 exit

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip protocols      -> router ID 4.4.4.4, GigabitEthernet0/0/0 passive
!---   show ip ospf neighbor  -> BC-1 (6.6.6.6) FULL/DR, BC-2 (5.5.5.5) FULL/BDR
!---   show ip route ospf     -> O*E2 0.0.0.0/0 learned from BC-1
! ==============================================================

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2.7.1 Packet Tracer - Single-Area OSPFv2 Configuration (Answers)