Lab Objective:
The focus of this lab is to understand OSPF implementation and configuration in Cisco IOS routers. Additional technologies tested include authentication, metrics and .
Lab Topology:
The lab network topology is illustrated below:
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IMPORTANT NOTE If you are using the www.howtonetwork.net racks, please bring up the LAN interfaces connected to the routers by issuing the no shutdown command on the connected switches. If you are using a home lab with no interface fastethernet 0/0 Alternately, you can simply connect the interfaces to a hub or switch if you have one available in your own lab. |
Task 1
Configure hostnames and IP addressing on all routers as illustrated in the network topology.
Task 2
Using legacy network x.x.x.x y.y.y.y area <area> OSPF configuration commands, configure OSPF area 0 as illustrated in the topology. Ensure that no OSPF Hellos are sent out of the LAN interfaces on R2 and R3. Verify your configuration using the appropriate commands.
Task 3
Using legacy network x.x.x.x y.y.y.y area <area> OSPF configuration commands, configure OSPF area 2 as illustrated in the topology. This area should not allow any inter-area LSAs (except for the default route) or any external LSAs.
Additionally, the router should not send log messages when Type 6 LSAs are received. Ensure that the default route shows up in the routing table of R4 with a route metric of 222. You are NOT allowed to modify any interface bandwidth or cost values to complete this task. Ensure that no OSPF packets are sent out of the LAN interface on R4. Verify your configuration using the appropriate commands.
Task 4
Using legacy network x.x.x.x y.y.y.y area <area> OSPF configuration commands, configure OSPF area 3 as illustrated in the topology. Authenticate OSPF messages between R1 and R2 using the plain text password ‘CCNP’. Authentication should be performed only at the interface level. Verify your configuration using the appropriate commands.
Task 5
Using legacy network x.x.x.x y.y.y.y area <area> OSPF configuration commands, configure OSPF area 1 as illustrated in the topology. Configure MD5 authentication for area 1 using the password ‘CCNP’. Verify your configuration.
Task 6
Using legacy network x.x.x.x y.y.y.y area <area> OSPF configuration commands, configure OSPF for area 5 as illustrated in the topology. In the future, an additional router will be added to this segment. This router will be redistributing external routes from business partner routers. Configure area 5 so that these routes can be imported into OSPF as Type 7 routes. No inter-area or Type 5 LSAs should be allowed into this area. Finally, ensure that all other routers in the network are able to ping R1s LAN (and any future area 5 subnets).Verify your configuration using the appropriate commands.
Task 7
Configure R1 so that the virtual link going to R2 is assigned a cost of 2 and the virtual link going to R3 is assigned a cost of 3. Verify your configuration.
Task 8
In the future, the FastEthernet link on R2 will be replaced with a GigabitEthernet link. Configure R2 so that OSPF accurately calculates route metrics when this is performed.
Lab Validation
Task 1
| Router(config)#hostname R1 R1(config)#interface fastethernet 0/0 R1(config-if)#no shutdown R1(config-if)#ip address 150.1.1.1 255.255.255.0 R1(config-if)#exit R1(config)#interface serial 0/0 R1(config-if)#no shutdown R1(config-if)#ip address 10.0.1.1 255.255.255.252 R1(config-if)#clock rate 2000000 R1(config-if)#exit R1(config)#interface serial 0/1 R1(config-if)#ip address 10.0.0.5 255.255.255.252 R1(config-if)#no shutdown R1(config-if)#exit |
| Router(config)#hostname R2 R2(config)#interface fastethernet 0/0 R2(config-if)#no shutdown R2(config-if)#ip address 150.2.2.2 255.255.255.0 R2(config-if)#exit R2(config)#interface serial 0/0 R2(config-if)#no shutdown R2(config-if)#ip address 10.0.1.2 255.255.255.252 R2(config-if)#exit R2(config)#interface serial 0/1 R2(config-if)#ip address 10.0.0.9 255.255.255.252 R2(config-if)#no shutdown R2(config-if)#exit |
| Router(config)#hostname R3 R3(config)#interface fastethernet 0/0 R3(config-if)#ip address 150.3.3.3 255.255.255.0 R3(config-if)#exit R3(config)#interface serial 1/0 R3(config-if)#ip address 10.0.0.6 255.255.255.252 R3(config-if)#no shutdown R3(config-if)# clock rate 128000 R3(config-if)#exit R3(config)#interface serial 1/1 R3(config-if)#ip address 10.0.0.10 255.255.255.252 R3(config-if)#no shutdown R3(config-if)# clock rate 128000 R3(config-if)#exit R3(config)#interface serial 1/2 R3(config-if)#ip address 10.0.0.13 255.255.255.252 R3(config-if)#no shutdown R3(config-if)# clock rate 128000 R3(config-if)#exit |
| Router(config)#hostname R4 R4(config)#interface fastethernet 0/0 R4(config-if)#ip address 150.4.4.4 255.255.255.0 R4(config-if)#exit R4(config)#interface serial 0/0 R4(config-if)#ip address 10.0.0.14 255.255.255.252 R4(config-if)#no shutdown R4(config-if)#exit |
Task 2
| R2(config)#router ospf 2 R2(config-router)#router-id 2.2.2.2 R2(config-router)#network 150.2.2.2 0.0.0.0 area 0 R2(config-router)#network 10.0.0.9 0.0.0.0 area 0 R2(config-router)#passive-interface fastethernet 0/0 R2(config-router)#exit |
| R3(config-if)#router ospf 3 R3(config-router)#router-id 3.3.3.3 R3(config-router)#network 150.3.3.3 0.0.0.0 area 0 R3(config-router)#network 10.0.0.10 0.0.0.0 area 0 R3(config-router)#passive-interface fastethernet 0/0 |
Verify your configuration using the show ip ospf neighbor command:
| R2#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface |
| R3#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface |
Task 3
This task requires that a totally stubby area be configured. To ensure that the default route shows up in R4s routing table with a metric of 222, you need to specify a cost value that is derived by subtracting the default interface cost of 64 from 222. The is completed as follows:
| R3(config)#router ospf 3 R3(config-router)#network 10.0.0.13 0.0.0.0 area 2 R3(config-router)#area 2 stub no-summary R3(config-router)#area 2 default-cost 158 R3(config-router)#exit |
| R4(config)#router ospf 4 R4(config-router)#router-id 4.4.4.4 R4(config-router)#network 150.4.4.4 0.0.0.0 area 2 R4(config-router)#network 10.0.0.14 0.0.0.0 area 2 R4(config-router)#passive-interface fastethernet 0/0 R4(config-router)#area 2 stub R4(config-router)#exit |
Verify your configuration using the show ip ospf neighbor command:
| R3#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface |
| R4#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface |
Next, verify that the default route has a route metric of 222 as required in the task:
| R4#show ip route ospf O*IA 0.0.0.0/0 [110/222] via 10.0.0.13, 00:01:50, Serial0/0 |
You can verify the cost value specified for the default route by looking at the LSA in the LSDB:
| R4#show ip ospf database summary 0.0.0.0
OSPF Router with ID (4.4.4.4) (Process ID 4) Summary Net Link States (Area 2) Routing Bit Set on this LSA |
Task 4
| R1(config)#router ospf 1 R1(config-router)#router-id 1.1.1.1 R1(config-router)#network 10.0.0.1 0.0.0.0 area 2 R1(config-router)#exit R1(config)#interface serial 0/0 R1(config-if)#ip ospf authentication R1(config-if)#ip ospf authentication-key CCNP R1(config-if)#exit |
| R2(config)#router ospf 2 R2(config-router)#network 10.0.0.2 0.0.0.0 area 2 R2(config-router)#exit R2(config)#interface serial 0/0 R2(config-if)#ip ospf authentication R2(config-if)#ip ospf authentication-key CCNP R2(config-if)#exit |
Verify your configuration using the show ip ospf neighbor command:
| R1#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface |
| R2#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface |
Verify authentication configuration using the show ip ospf interface command:
| R1#show ip ospf interface serial 0/0 Serial0/0 is up, line protocol is up Internet Address 10.0.0.1/30, Area 2 Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 64 Transmit Delay is 1 sec, State POINT_TO_POINT Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:02 Supports Link-local Signaling (LLS) Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 2.2.2.2 Suppress hello for 0 neighbor(s) Simple password authentication enabled |
Task 5
| R1(config)#router ospf 1 R1(config-router)#network 10.0.0.5 0.0.0.0 area 1 R1(config-router)#area 1 authentication message-digest R1(config-router)#exit R1(config)#interface serial 0/1 R1(config-if)#ip ospf message-digest-key 1 md5 CCNP R1(config-if)#exit |
| R3(config)#router ospf 3 R3(config-router)#network 10.0.0.6 0.0.0.0 area 1 R3(config-router)#area 1 authentication message-digest R3(config-router)#exit R3(config)#interface serial 1/0 R3(config-if)#ip ospf message-digest-key 1 md5 CCNP R3(config-if)#exit |
Verify your configuration using the show ip ospf neighbor command:
| R1#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface |
| R3#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface |
Verify area authentication configuration using the show ip ospf command:
| R3#show ip ospf | begin Area 1 Area 1 Number of interfaces in this area is 1 Area has message digest authentication SPF algorithm last executed 00:03:18.600 ago SPF algorithm executed 2 times Area ranges are Number of LSA 8. Checksum Sum 0x03AA2E Number of opaque link LSA 0. Checksum Sum 0x000000 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0 |
Verify interface authentication using the show ip ospf interface command:
| R3#show ip ospf interface serial 1/0 Serial1/0 is up, line protocol is up Internet Address 10.0.0.6/30, Area 1 Process ID 3, Router ID 3.3.3.3, Network Type POINT_TO_POINT, Cost: 781 Transmit Delay is 1 sec, State POINT_TO_POINT Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:08 Supports Link-local Signaling (LLS) Index 1/4, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 1.1.1.1 Suppress hello for 0 neighbor(s) Message digest authentication enabled Youngest key id is 1 |
Task 6
This task requires the implementation of area 5 as a totally stubby NSSA. This configuration will allow a default route to be advertised into the area. It will also allow the external routes from the business partners to be advertised to the rest of the domain. Finally, you need to configure two virtual links to connect area 5 to the OSPF backbone. One virtual link will use area 1 as the transit area and the other will use area 3. This task is completed as follows:
| R1(config)#router ospf 1 R1(config-router)#network 150.1.1.1 0.0.0.0 area 5 R1(config-router)#area 5 nssa no-summary R1(config-router)#area 1 virtual-link 3.3.3.3 R1(config-router)#area 2 virtual-link 2.2.2.2 R1(config-router)#exit |
| R2(config)#router ospf 2 R2(config-router)#area 2 virtual-link 1.1.1.1 R2(config-router)#exit |
| R3(config)#router ospf 3 R3(config-router)#area 1 virtual-link 1.1.1.1 R3(config-router)#exit |
Verify OSPF virtual link states using the show ip ospf neighbor command:
| R1#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface |
View detailed virtual link information using the show ip ospf virtual-links command:
| R1#show ip ospf virtual-links Virtual Link OSPF_VL1 to router 2.2.2.2 is up Run as demand circuit DoNotAge LSA allowed. Transit area 2, via interface Serial0/0, Cost of using 64 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:02 Adjacency State FULL (Hello suppressed) Index 1/3, retransmission queue length 0, number of retransmission 0 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 0, maximum is 0 Last retransmission scan time is 0 msec, maximum is 0 msec Virtual Link OSPF_VL0 to router 3.3.3.3 is up Run as demand circuit DoNotAge LSA allowed. Transit area 1, via interface Serial0/1, Cost of using 64 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:05 Adjacency State FULL (Hello suppressed) Index 2/4, retransmission queue length 0, number of retransmission 0 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 0, maximum is 0 Last retransmission scan time is 0 msec, maximum is 0 msec |
Finally, verify that the 150.1.1.0/24 subnet exist in the routing table of all routers. For example, on R3, you should see the following route entry:
| R3#show ip route ospf 10.0.0.0/30 is subnetted, 4 subnets O IA 10.0.0.0 [110/845] via 10.0.0.9, 00:03:26, Serial1/1 [110/845] via 10.0.0.5, 00:03:26, Serial1/0 150.1.0.0/24 is subnetted, 1 subnets O 150.1.1.0 [110/782] via 10.0.0.14, 00:10:45, Serial1/2 150.2.0.0/24 is subnetted, 1 subnets O 150.2.2.0 [110/782] via 10.0.0.9, 00:03:26, Serial1/1 |
Additionally, verify connectivity by pinging LAN-to-LAN between R1 and R4:
| R4#ping 150.1.1.1 source 150.4.4.4 repeat 10 size 1500
Type escape sequence to abort. |
Task 7
By default, the virtual link cost is derived from the interface cost. To modify the virtual link cost, you need to modify the cost of the interface the virtual link is established across. Before any changes are made to the network, the virtual links on R1 show the following costs:
| R1#show ip ospf virtual-links Virtual Link OSPF_VL1 to router 2.2.2.2 is up Run as demand circuit DoNotAge LSA allowed. Transit area 2, via interface Serial0/0, Cost of using 64 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:02 Adjacency State FULL (Hello suppressed) Index 1/3, retransmission queue length 0, number of retransmission 0 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 0, maximum is 0 Last retransmission scan time is 0 msec, maximum is 0 msec Virtual Link OSPF_VL0 to router 3.3.3.3 is up Run as demand circuit DoNotAge LSA allowed. Transit area 1, via interface Serial0/1, Cost of using 64 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:05 Adjacency State FULL (Hello suppressed) Index 2/4, retransmission queue length 0, number of retransmission 0 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 0, maximum is 0 Last retransmission scan time is 0 msec, maximum is 0 msec |
To complete this task, implement the following configuration:
| R1(config)#interface serial 0/0 R1(config-if)#ip ospf cost 2 R1(config-if)#exit R1(config)#interface serial 0/1 R1(config-if)#ip ospf cost 3 R1(config-if)#exit |
Verify the new costs using the show ip ospf virtual-links command:
| R1#show ip ospf virtual-links Virtual Link OSPF_VL1 to router 2.2.2.2 is up Run as demand circuit DoNotAge LSA allowed. Transit area 2, via interface Serial0/0, Cost of using 2 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:08 Adjacency State FULL (Hello suppressed) Index 1/3, retransmission queue length 0, number of retransmission 0 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 0, maximum is 0 Last retransmission scan time is 0 msec, maximum is 0 msec Virtual Link OSPF_VL0 to router 3.3.3.3 is up Run as demand circuit DoNotAge LSA allowed. Transit area 1, via interface Serial0/1, Cost of using 3 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:01 Adjacency State FULL (Hello suppressed) Index 2/4, retransmission queue length 0, number of retransmission 0 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 0, maximum is 0 Last retransmission scan time is 0 msec, maximum is 0 msec |
Task 8
By default, OSPF uses a reference bandwidth of 100Mbps when calculating cost values for links. If you change this value on one router – change it on every other router otherwise this could result in inconsistent routing information. Complete this task by implementing the following:
| R1(config)#router ospf 1 R1(config-router)#auto-cost reference-bandwidth 1000 % OSPF: Reference bandwidth is changed. Please ensure reference bandwidth is consistent across all routers. R1(config-router)#exit |
| R2(config)#router ospf 2 R2(config-router)#auto-cost reference-bandwidth 1000 % OSPF: Reference bandwidth is changed. Please ensure reference bandwidth is consistent across all routers. R2(config-router)#exit |
| R3(config)#router ospf 3 R3(config-router)#auto-cost reference-bandwidth 1000 % OSPF: Reference bandwidth is changed. Please ensure reference bandwidth is consistent across all routers. R3(config-router)#exit |
| R4(config)#router ospf 1 R4(config-router)#auto-cost reference-bandwidth 1000 % OSPF: Reference bandwidth is changed. Please ensure reference bandwidth is consistent across all routers. R4(config-router)#exit |
Verify the default reference bandwidth using the show ip protocols command:
| R4#show ip protocols Routing Protocol is “ospf 4” Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 4.4.4.4 Number of areas in this router is 1. 0 normal 1 stub 0 nssa Maximum path: 4 Routing for Networks: 10.0.0.14 0.0.0.0 area 2 150.4.4.4 0.0.0.0 area 2 Reference bandwidth unit is 1000 mbps Passive Interface(s): FastEthernet0/0 Routing Information Sources: Gateway Distance Last Update 3.3.3.3 110 00:02:15 Distance: (default is 110) |
Final Router Configurations
R1
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R1#term len 0 Current configuration : 1266 bytes R1# |
R2
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R2#term len 0 Current configuration : 1119 bytes R2# |
R3
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R3#term len 0 Current configuration : 1577 bytes R3# |
R4
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R4#term len 0 Current configuration : 1003 bytes R4# |