The purpose of this lab is to present the two of the four OSPF network types that you can use with Frame Relay: Point-to-point and Multipoint and some issues you may encounter because mainly, OSPF works differently on each type. Wendell Odom in his book, CCNP Route Official Certification Guide outlined the three important points when using OSPF over Frame Relay which is basically the inspiration of this lab.
R1
hostname R1
!
interface Loopback0
ip address 10.2.1.1 255.255.255.0
!
interface Serial0/0
no ip address
encapsulation frame-relay
no shutdown
!
interface Serial0/0.2 point-to-point
ip address 10.2.12.1 255.255.255.0
!
interface Serial0/0.3 point-to-point
ip address 10.2.13.1 255.255.255.0
!
interface Serial0/0.45 multipoint
ip address 10.2.145.1 255.255.255.0
!
router ospf 1
log-adjacency-changes
network 10.2.0.0 0.0.255.255 area 0
R2
hostname R2
!
interface Loopback0
ip address 10.2.2.2 255.255.255.0
!
interface Serial0/0
ip address 10.2.12.2 255.255.255.0
encapsulation frame-relay
ip ospf network point-to-point
no shutdown
!
router ospf 1
log-adjacency-changes
network 10.2.0.0 0.0.255.255 area 0
R3
hostname R3
!
interface Loopback0
ip address 10.2.3.3 255.255.255.0
!
interface Serial0/0
ip address 10.2.13.3 255.255.255.0
encapsulation frame-relay
ip ospf network point-to-point
no frame-relay inverse-arp
no shutdown
!
router ospf 1
log-adjacency-changes
network 10.2.0.0 0.0.255.255 area 0
R4
hostname R4
!
interface Loopback0
ip address 10.2.4.4 255.255.255.0
!
interface Serial0/0
ip address 10.2.145.4 255.255.255.0
encapsulation frame-relay
no shutdown
!
router ospf 1
log-adjacency-changes
network 10.2.0.0 0.0.255.255 area 0
R5
hostname R5
!
interface Loopback0
ip address 10.2.5.5 255.255.255.0
!
interface Serial0/0
ip address 10.2.145.5 255.255.255.0
encapsulation frame-relay
no shutdown
!
router ospf 1
log-adjacency-changes
network 10.2.0.0 0.0.255.255 area 0
Configure the port/dlci mapping on the frame-relay switch as shown below
R1 (s0/0) <--> FR Port 1
R2 (s0/0) <--> FR Port 10
R3 (s0/0) <--> FR Port 11
R4 (s0/0) <--> FR Port 12
R5 (s0/0) <--> FR Port 13
Helpful show sommands:
show frame-relay pvc
show frame-relay map
show ip ospf neighbor
show ip ospf interface name/type
show ip route
From the base configuration, you will notice that OSPF process is already running on all routers and enabled on all the interfaces connected to the Frame Relay network: R1’s subinterfaces (s0/0.2, s0/0.3, s0/0.45, loopback 0), R2, R3, R4 and R5's s0/0 and loopback 0 interfaces. Your task is to figure out why OSPF neighbor relationship does not work as well as what is causing the network reachability issues on some part of the network. The thing is, you will not be removing any command nor change existing commands; you only need to find the missing command and add it to the existing configuration.
At this point, all interfaces mentioned above must be in up/up status. Otherwise, check the port/dlci mapping on your frame-relay switch.
Task 1: Neighbor relationship between R1 and R2
R1's s0/0.2 and R2's s0/0 interface are running point-to-point ospf network type. For R1 and R2 to discover each other and become fully adjacent, find out the one missing command in R1.
Task 2: Neighbor relationship between R1 and R3
R1's s0/0.3 and R3's s0/0 interface are running point-to-point ospf network type. For R1 and R3 to discover each other and become fully adjacent:
a) Find out the one missing command in R1
b) After completing the task 2a, if you issue show ip ospf neighbor on R3, you will see that it is listing R1 as neighbor but it is only in INIT state. Use that as a clue to find the one missing command in R3.
Task 3: Neighbor relationship between R1 and R4 then R1 and R5
R1's s0/0.45 is running multipoint (nonbroadcast) ospf network type. For R1 to discover R4 and R5 become fully adjacent:
a) Find out the missing frame-relay command in R1 for each potential ospf neighbor
b) Find out the missing ospf command in R1 for each potential ospf neighbor
Task 4: Network Reachability between R4 and R5
Now that R1 is fully adjacent with R4 and R5, if you issue show ip route ospf command in R5, you should see all other router's subnet in the routing table. However, if you try pinging the subnet of R4, it will fail while it has no problem reaching the subnets of R1, R2 and R3. Find out the one missing command both in R4 and R5 to fix the network reachability issue.
Final Output:
R1#sh ip ospf neigh
Neighbor ID Pri State Dead Time Address Interface
10.2.5.5 1 FULL/DR 00:01:55 10.2.145.5 Serial0/0.45
10.2.4.4 1 FULL/DROTHER 00:01:50 10.2.145.4 Serial0/0.45
10.2.3.3 0 FULL/ - 00:00:37 10.2.13.3 Serial0/0.3
10.2.2.2 0 FULL/ - 00:00:31 10.2.12.2 Serial0/0.2
R5#ping 10.2.4.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.4.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 44/80/104 ms
Key Points (from Wendell Odom's CCNP Route Certification Guide, Chapter 8)
- If the configured network type allows for neighbor discovery using Hellos, and you use InARP, the neighbors should be discovered.
- If the configured network type allows for neighbor discovery, and you use frame-relay map, ensure that the broadcast keyword is included.
- If the configured network type does not allow for neighbor discovery, statically configure neighbors.
Comments
Post a Comment