Lab Objective:
The focus of this lab is to understand OSPF implementation and configuration in Cisco IOS routers. Additional technologies tested include Frame Relay connectivity and path control.
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. Also, if you are using the www.howtonetwork.net racks, configure R3 as the Frame Relay switch using the following configuration commands: hostname R3-Frame-Relay-Switch |
Task 1
Configure hostnames and IP addressing on all routers as illustrated in the network topology.
Task 2
Configure the Frame Relay network so that all routers can ping each others’ WAN interfaces.
Task 3
Using interface-based configuration, configure OSPF  area 0 on the Frame Relay WAN between  R1, R2, and R4. Configure OSPF so that there is no DR/BDR election held over the Frame Relay WAN. Ensure that OSPF uses ONLY Unicast packets and not Multicast packets over the Frame Relay WAN. Verify your configuration using the appropriate commands.
Task 4
Advertise the 150.1.1.0/24 subnet connected to the LAN segment on R1 via OSPF. This subnet should be advertised as a Type 1 External LSA with a route tag of 111 and metric of 111.
Task 5
Using interface-based configuration, configure OSPF area 1 on the LAN between R2 and R4. In your configuration, ensure that R2 is elected master during the DBD exchange; however, R4 should be elected as the DR for the segment. Verify your configuration using the appropriate commands and debugs.
Task 6
Configure OSPF so that R1 prefers the path via R2 to reach the 150.5.5.0/24 subnet. If this path is unavailable, the path via R4 should be used. Verify your configuration.
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 0/1 R1(config-if)#ip address 10.0.0.1 255.255.255.0 R1(config-if)#no shutdown R1(config-if)#encapsulation frame-relay R1(config-if)#exit |
| Router(config)#hostname R2 R2(config)#interface fastethernet 0/0 R2(config-if)#no shutdown R2(config-if)#ip address 150.5.5.2 255.255.255.0 R2(config-if)#exit R2(config)#interface serial 0/1 R2(config-if)#ip address 10.0.0.2 255.255.255.0 R2(config-if)#no shutdown R2(config-if)#encapsulation frame-relay R2(config-if)#exit |
| Router(config)#hostname R4 R4(config)#interface fastethernet 0/0 R4(config-if)#no shutdown R4(config-if)#ip address 150.5.5.4 255.255.255.0 R4(config-if)#exit R4(config)#interface serial 0/0 R4(config-if)#ip address 10.0.0.4 255.255.255.0 R4(config-if)#no shutdown R4(config-if)#encapsulation frame-relay R4(config-if)#exit |
Task 2
Although Frame Relay configuration is not a CCNP topic, per se, it is still important that you remember your Frame Relay configurations from the CCNA. The task is completed as follows:
| R1(config)#interface serial 0/1 R1(config-if)#frame-relay map ip 10.0.0.2 102 broadcast R1(config-if)#frame-relay map ip 10.0.0.4 104 broadcast R1(config-if)#exit |
On the spoke routers, because the same DLCI is being used, the broadcast keyword should only be specified once to avoid duplicate Broadcast packets across the Frame Relay WAN. This task is completed as follows:
| R2(config)#interface serial 0/1 R2(config-if)#frame-relay map ip 10.0.0.1 201 broadcast R2(config-if)#frame-relay map ip 10.0.0.4 201Â Â Â Â Â Â Â Â Â R2(config-if)#exit |
| R4(config)#interface serial 0/0 R4(config-if)#frame-relay map ip 10.0.0.1 401 broadcast R4(config-if)#frame-relay map ip 10.0.0.2 401Â Â Â Â Â Â Â Â Â R4(config-if)#exit |
Verify your Frame Relay configuration using the show frame-relay map command:
| R1#show frame-relay map Serial0/1 (up): ip 10.0.0.2 dlci 102(0x66,0x1860), static, broadcast, CISCO, status defined, active Serial0/1 (up): ip 10.0.0.4 dlci 104(0x68,0x1880), static, broadcast, CISCO, status defined, active |
| R2#show frame-relay map Serial0/1 (up): ip 10.0.0.1 dlci 201(0xC9,0x3090), static, broadcast, CISCO, status defined, active Serial0/1 (up): ip 10.0.0.4 dlci 201(0xC9,0x3090), static, CISCO, status defined, active |
| R4#show frame-relay map Serial0/0 (up): ip 10.0.0.1 dlci 401(0x191,0x6410), static, broadcast, CISCO, status defined, active Serial0/0 (up): ip 10.0.0.2 dlci 401(0x191,0x6410), static, CISCO, status defined, active |
Finally, verify that you can ping between all routers across the Frame Relay WAN:
| R1#ping 10.0.0.2 repeat 10
Type escape sequence to abort. Type escape sequence to abort. |
| R2#ping 10.0.0.1 repeat 10
Type escape sequence to abort. Type escape sequence to abort. |
| R4#ping 10.0.0.1 repeat 10
Type escape sequence to abort. Type escape sequence to abort. |
Task 3
To ensure that there is no DR/BDR election and allow OSPF to use Unicast and not Multicast packets, you need to specify a point-to-multipoint non-broadcast network type. This network type requires the static configuration of neighbors, which exchange updates using Unicast versus Multicast. This task is completed as follows:
| R1(config)#router ospf 1 R1(config-router)#router-id 1.1.1.1 R1(config-router)#neighbor 10.0.0.2 R1(config-router)#neighbor 10.0.0.4 R1(config-router)#exit R1(config)#interface serial 0/1 R1(config-if)#ip ospf network point-to-multipoint non-broadcast R1(config-if)#ip ospf 1 area 0 R1(config-if)#exit |
| R2(config)#router ospf 2 R2(config-router)#router-id 2.2.2.2 R2(config-router)#neighbor 10.0.0.1 R2(config-router)#exit R2(config)#interface serial 0/1 R2(config-if)#ip ospf network point-to-multipoint non-broadcast R2(config-if)#ip ospf 2 area 0 R2(config-if)#exit |
| R4(config)#router ospf 4 R4(config-router)#router-id 4.4.4.4 R4(config-router)#neighbor 10.0.0.1 R4(config-router)#exit R4(config)#interface serial 0/0 R4(config-if)#ip ospf network point-to-multipoint non-broadcast R4(config-if)#ip ospf 4 area 0 R4(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 |
| R4#show ip ospf neighbor
Neighbor ID    Pri  State      Dead Time  Address        Interface |
Task 4
| R1(config)#router ospf 1 R1(config-router)#redis connected subnets metric-type 1 metric 111 tag 111Â Â Â Â Â R1(config-router)#exit |
Verify your configuration by looking at the external LSA for the 150.1.1.0/24 subnet:
| R1#show ip ospf database external 150.1.1.0
           OSPF Router with ID (1.1.1.1) (Process ID 1)                Type-5 AS External Link States  LS age: 37 |
Task 5
The OSPF master/slave election process is based solely on IP address (the highest wins), while the DR/BDR election process is based on priority or IP address. To ensure that R2 is elected master during the database exchange process, it needs to be configured with a higher IP address. To ensure that R4 is elected DR, it needs to be configured with a higher priority. This task is completed as follows:
| R2(config)#router ospf 2 R2(config-router)#router-id 22.22.22.22 Reload or use “clear ip ospf process” command, for this to take effect R2(config-router)#exit R2(config)#interface fastethernet 0/0 R2(config-if)#ip ospf 2 area 1 R2(config-if)#end R2#clear ip ospf process Reset ALL OSPF processes? [no]: yes |
| R4(config)#interface fastethernet 0/0 R4(config-if)#ip ospf 4 area 1 R4(config-if)#ip ospf priority 4 R4(config-if)#end R4#clear ip ospf process Reset ALL OSPF processes? [no]: yes |
You can verify the master/slave and DR/BDR election process using the debug ip ospf adj command on either R2 or R4 after resetting the adjacency:
| R2#debug ip ospf adj OSPF adjacency events debugging is on R2#clear ip ospf process Reset ALL OSPF processes? [no]: yes R2# R2# R2# R2# [Truncated Output] *May 10 08:24:58.678: OSPF: DR/BDR election on FastEthernet0/0 |
Task 6
Unlike in the previous lab, in this lab you can specify a per-neighbor cost because of the point-to-multipoint non-broadcast network type. Prior to any changes being made to the current OSPF routing configuration, the routing table on router R1 shows the following route entries:
| R1#show ip ro ospf 10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks OÂ Â Â Â Â Â 10.0.0.2/32 [110/64] via 10.0.0.2, 00:05:13, Serial0/1 OÂ Â Â Â Â Â 10.0.0.4/32 [110/64] via 10.0.0.4, 00:05:13, Serial0/1 150.5.0.0/24 is subnetted, 1 subnets O IAÂ Â Â 150.5.5.0 [110/65] via 10.0.0.4, 00:05:13, Serial0/1 Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â [110/65] via 10.0.0.2, 00:05:13, Serial0/1 |
Complete this task by either decreasing the cost of neighbor R2 to a value less than 64:
| R1(config)#router ospf 1 R1(config-router)#neighbor 10.0.0.2 cost 1 R1(config-router)#exit |
Following this change, the routing table on R1 now shows the following route entries:
| R1#show ip route ospf 10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks OÂ Â Â Â Â Â 10.0.0.2/32 [110/1] via 10.0.0.2, 00:00:47, Serial0/1 OÂ Â Â Â Â Â 10.0.0.4/32 [110/64] via 10.0.0.4, 00:00:47, Serial0/1 150.5.0.0/24 is subnetted, 1 subnets O IAÂ Â Â 150.5.5.0 [110/2] via 10.0.0.2, 00:00:47, Serial0/1 |
Final Router Configurations
R1
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R1#term len 0 Current configuration : 1141 bytes |
R2
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R2#term len 0 Current configuration : 1042 bytes |
R3
| R3-Frame-Relay-Switch#term len 0 R3-Frame-Relay-Switch#sh run Building configuration… Current configuration : 1556 bytes |
R4
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R4#term len 0 Current configuration : 1077 bytes |