Topology
Addressing Table
|
Device
|
Interface
|
IP Address
|
Subnet Mask
|
Default Gateway
|
|
R1
|
G0/0
|
192.168.1.1
|
255.255.255.0
|
N/A
|
|
|
S0/0/0 (DCE)
|
192.168.12.1
|
255.255.255.252
|
N/A
|
|
|
S0/0/1
|
192.168.13.1
|
255.255.255.252
|
N/A
|
|
R2
|
G0/0
|
192.168.2.1
|
255.255.255.0
|
N/A
|
|
|
S0/0/0
|
192.168.12.2
|
255.255.255.252
|
N/A
|
|
|
S0/0/1 (DCE)
|
192.168.23.1
|
255.255.255.252
|
N/A
|
|
R3
|
G0/0
|
192.168.3.1
|
255.255.255.0
|
N/A
|
|
|
S0/0/0 (DCE)
|
192.168.13.2
|
255.255.255.252
|
N/A
|
|
|
S0/0/1
|
192.168.23.2
|
255.255.255.252
|
N/A
|
|
PC-A
|
NIC
|
192.168.1.3
|
255.255.255.0
|
192.168.1.1
|
|
PC-B
|
NIC
|
192.168.2.3
|
255.255.255.0
|
192.168.2.1
|
|
PC-C
|
NIC
|
192.168.3.3
|
255.255.255.0
|
192.168.3.1
|
Objectives
Part 1: Build the Network and
Configure Basic Device Settings
Part 2: Configure and Verify OSPF
Routing
Part 3: Change Router ID Assignments
Part 4: Configure OSPF Passive
Interfaces
Part 5: Change OSPF Metrics
Background / Scenario
Open Shortest Path First (OSPF) is a link-state
routing protocol for IP networks. OSPFv2 is defined for IPv4 networks, and
OSPFv3 is defined for IPv6 networks. OSPF detects changes in the topology, such
as link failures, and converges on a new loop-free routing structure very
quickly. It computes each route using Dijkstra’s algorithm, a shortest path
first algorithm.
In this lab, you will configure the
network topology with OSPFv2 routing, change the router ID assignments,
configure passive interfaces, adjust OSPF metrics, and use a number of CLI
commands to display and verify OSPF routing information.
Note: The routers used with CCNA hands-on labs
are Cisco 1941 Integrated Services Routers (ISRs) with Cisco IOS Release 15.2(4)M3
(universalk9 image). Other routers and Cisco IOS versions can be used. Depending
on the model and Cisco IOS version, the commands available and output produced
might vary from what is shown in the labs. Refer to the Router Interface
Summary Table at the end of this lab for the correct interface identifiers.
Note: Make sure that the routers have been erased and have no startup
configurations. If you are unsure, contact your instructor.
Required Resources
·
3 Routers (Cisco 1941 with
Cisco IOS Release 15.2(4)M3 universal image or comparable)
·
3 PCs (Windows 7, Vista, or XP
with terminal emulation program, such as Tera Term)
·
Console cables to configure the
Cisco IOS devices via the console ports
·
Ethernet and serial cables as
shown in the topology
Part 1:
Build the Network and Configure
Basic Device Settings
In Part 1, you set up the network
topology and configure basic settings on the PC hosts and routers.
Step 1:
Cable the network as shown in
the topology.
Step 2:
Initialize and reload the routers
as necessary.
Step 3:
Configure basic settings for
each router.
a.
Disable DNS lookup.
b.
Configure device name as shown
in the topology.
c.
Assign class as the privileged EXEC password.
d.
Assign cisco as the console and vty passwords.
e.
Configure a message of the day
(MOTD) banner to warn users that unauthorized access is prohibited.
f.
Configure logging synchronous for the console line.
g.
Configure the IP address listed
in the Addressing Table for all interfaces.
h.
Set the clock rate for all DCE
serial interfaces at 128000.
i.
Copy the running configuration
to the startup configuration.
Step 4:
Configure PC hosts.
Step 5:
Test connectivity.
The routers should be able to ping one
another, and each PC should be able to ping its default gateway. The PCs are unable
to ping other PCs until OSPF routing is configured. Verify and troubleshoot if
necessary.
Part 2:
Configure and Verify OSPF
Routing
In Part 2, you will configure OSPFv2
routing on all routers in the network and then verify that routing tables are
updated correctly. After OSPF has been verified, you will configure OSPF
authentication on the links for added security.
Step 1:
Configure OSPF on R1.
a.
Use the router ospf command in global configuration mode to enable OSPF on
R1.
R1(config)# router
ospf 1
Note: The OSPF process id is kept locally and has no meaning to other
routers on the network.
b.
Configure the network statements for the networks on
R1. Use an area ID of 0.
R1(config-router)# network 192.168.1.0 0.0.0.255 area 0
R1(config-router)# network 192.168.12.0 0.0.0.3 area 0
R1(config-router)# network 192.168.13.0 0.0.0.3 area 0
Step 2:
Configure OSPF on R2 and R3.
Use the router ospf command and add the network statements for the networks on R2 and R3. Neighbor adjacency
messages display on R1 when OSPF routing is configured on R2 and R3.
R1#
00:22:29: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.23.1 on Serial0/0/0
from LOADING to FULL, Loading Done
R1#
00:23:14: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.23.2 on Serial0/0/1
from LOADING to FULL, Loading Done
R1#
Step 3:
Verify OSPF neighbors and routing
information.
a.
Issue the show ip ospf neighbor command to verify that each router lists the
other routers in the network as neighbors.
R1# show
ip ospf neighbor
Neighbor ID Pri
State Dead Time Address Interface
192.168.23.2 0
FULL/ - 00:00:33 192.168.13.2 Serial0/0/1
192.168.23.1 0
FULL/ - 00:00:30 192.168.12.2 Serial0/0/0
b.
Issue the show ip route command to verify that all networks display in the
routing table on all routers.
R1# show
ip route
Codes: L - local, C - connected, S -
static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.1.0/24 is directly connected, GigabitEthernet0/0
L
192.168.1.1/32 is directly connected, GigabitEthernet0/0
O 192.168.2.0/24 [110/65] via
192.168.12.2, 00:32:33, Serial0/0/0
O 192.168.3.0/24 [110/65] via
192.168.13.2, 00:31:48, Serial0/0/1
192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.12.0/30 is directly connected, Serial0/0/0
L
192.168.12.1/32 is directly connected, Serial0/0/0
192.168.13.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.13.0/30 is directly connected, Serial0/0/1
L
192.168.13.1/32 is directly connected, Serial0/0/1
192.168.23.0/30 is subnetted, 1 subnets
O 192.168.23.0/30 [110/128]
via 192.168.12.2, 00:31:38, Serial0/0/0
[110/128]
via 192.168.13.2, 00:31:38, Serial0/0/1
What command would you use to only see
the OSPF routes in the routing table?
_______________________________________________________________________________________
Step 4:
Verify OSPF protocol settings.
The show
ip protocols command is a quick way to verify vital OSPF configuration
information. This information includes the OSPF process ID, the router ID,
networks the router is advertising, the neighbors the router is receiving
updates from, and the default administrative distance, which is 110 for OSPF.
R1# show
ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 192.168.13.1
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.1.0 0.0.0.255 area 0
192.168.12.0 0.0.0.3 area 0
192.168.13.0 0.0.0.3 area 0
Routing Information Sources:
Gateway Distance Last Update
192.168.23.2 110 00:19:16
192.168.23.1 110 00:20:03
Distance: (default is 110)
Step 5:
Verify OSPF process
information.
Use the show ip ospf command to examine the OSPF process ID and router ID. This
command displays the OSPF area information, as well as the last time the SPF
algorithm was calculated.
R1# show
ip ospf
Routing Process "ospf 1" with ID 192.168.13.1
Start time: 00:20:23.260, Time elapsed:
00:25:08.296
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
Supports NSSA (compatible with RFC 3101)
Event-log enabled, Maximum number of events:
1000, Mode: cyclic
Router is not originating router-LSAs with
maximum metric
Initial SPF schedule delay 5000 msecs
Minimum hold time between two consecutive SPFs
10000 msecs
Maximum wait time between two consecutive SPFs
10000 msecs
Incremental-SPF disabled
Minimum LSA interval 5 secs
Minimum LSA arrival 1000 msecs
LSA
group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Number of external LSA 0. Checksum Sum
0x000000
Number of opaque AS LSA 0. Checksum Sum
0x000000
Number of DCbitless external and opaque AS LSA
0
Number of DoNotAge external and opaque AS LSA
0
Number of areas in this router is 1. 1 normal
0 stub 0 nssa
Number of areas transit capable is 0
External flood list length 0
IETF
NSF helper support enabled
Cisco NSF helper support enabled
Reference bandwidth unit is 100 mbps
Area BACKBONE(0)
Number of interfaces in this area is 3
Area has no authentication
SPF algorithm last
executed 00:22:53.756 ago
SPF algorithm executed 7 times
Area ranges are
Number of LSA 3. Checksum Sum 0x019A61
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
Step 6:
Verify OSPF interface settings.
a.
Issue the show ip ospf interface brief command to display a summary of OSPF-enabled
interfaces.
R1# show
ip ospf interface brief
Interface
PID Area IP Address/Mask Cost
State Nbrs F/C
Se0/0/1
1 0 192.168.13.1/30 64
P2P 1/1
Se0/0/0
1 0 192.168.12.1/30 64
P2P 1/1
Gi0/0
1 0 192.168.1.1/24 1
DR 0/0
b.
For a more detailed list of
every OSPF-enabled interface, issue the show
ip ospf interface command.
R1# show
ip ospf interface
Serial0/0/1 is up, line protocol is up
Internet Address 192.168.13.1/30, Area 0, Attached via Network Statement
Process ID 1, Router ID 192.168.13.1, Network Type POINT_TO_POINT, Cost:
64
Topology-MTID Cost Disabled
Shutdown Topology Name
0 64 no no Base
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 00:00:01
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 3/3, 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 192.168.23.2
Suppress hello for 0 neighbor(s)
Serial0/0/0 is up, line protocol is up
Internet Address 192.168.12.1/30, Area 0, Attached via Network Statement
Process ID 1, Router ID 192.168.13.1, Network Type POINT_TO_POINT, Cost:
64
Topology-MTID Cost Disabled
Shutdown Topology Name
0 64 no no Base
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 00:00:03
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 2/2, 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 192.168.23.1
Suppress hello for 0 neighbor(s)
GigabitEthernet0/0 is up, line protocol is
up
Internet Address 192.168.1.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 192.168.13.1, Network Type BROADCAST, Cost: 1
Topology-MTID Cost
Disabled Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 192.168.13.1, Interface address 192.168.1.1
No
backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:01
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
Step 7:
Verify end-to-end connectivity.
Each PC should be able to ping the other
PCs in the topology. Verify and troubleshoot if necessary.
Note: It may be necessary to disable the PC firewall to ping between
PCs.
Part 3:
Change Router ID Assignments
The OSPF router ID is used to uniquely
identify the router in the OSPF routing domain. Cisco routers derive the router
ID in one of three ways and with the following precedence:
1)
IP address configured with the
OSPF router-id command, if present
2)
Highest IP address of any of
the router’s loopback addresses, if present
3)
Highest active IP address on
any of the router’s physical interfaces
Because no router IDs or loopback
interfaces have been configured on the three routers, the router ID for each
router is determined by the highest IP address of any active interface.
In Part 3, you will change the OSPF
router ID assignment using loopback addresses. You will also use the router-id command to change the router ID.
Step 1:
Change router IDs using
loopback addresses.
a.
Assign an IP address to
loopback 0 on R1.
R1(config)# interface
lo0
R1(config-if)# ip address 1.1.1.1 255.255.255.255
R1(config-if)# end
b.
Assign IP addresses to Loopback
0 on R2 and R3. Use IP address 2.2.2.2/32 for R2 and 3.3.3.3/32 for R3.
c.
Save the running configuration
to the startup configuration on all three routers.
d.
You must reload the routers in
order to reset the router ID to the loopback address. Issue the reload command on all three routers.
Press Enter to confirm the reload.
e.
After the router completes the
reload process, issue the show ip protocols
command to view the new router ID.
R1# show
ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 1.1.1.1
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.1.0 0.0.0.255 area 0
192.168.12.0 0.0.0.3 area 0
192.168.13.0 0.0.0.3 area 0
Routing Information Sources:
Gateway Distance Last Update
3.3.3.3 110 00:01:00
2.2.2.2 110 00:01:14
Distance: (default is 110)
f.
Issue the show ip ospf neighbor command to display the router ID changes for
the neighboring routers.
R1# show
ip ospf neighbor
Neighbor ID Pri
State Dead Time Address Interface
3.3.3.3 0
FULL/ - 00:00:35 192.168.13.2 Serial0/0/1
2.2.2.2 0
FULL/ - 00:00:32 192.168.12.2 Serial0/0/0
R1#
Step 2:
Change the router ID on R1
using the router-id command.
The preferred method for setting the
router ID is with the router-id
command.
a.
Issue the router-id 11.11.11.11 command on R1 to reassign the router ID.
Notice the informational message that appears when issuing the router-id command.
R1(config)# router
ospf 1
R1(config-router)# router-id 11.11.11.11
Reload or use "clear ip ospf process" command, for this to
take effect
R1(config)# end
b.
You will receive an
informational message telling you that you must either reload the router or use
the clear ip ospf process command
for the change to take effect. Issue the clear
ip ospf process command on all three routers. Type yes to reply to the reset verification message, and press ENTER.
c.
Set the router ID for R2 to 22.22.22.22 and the router ID for R3 to
33.33.33.33. Then use clear ip ospf process command to reset
ospf routing process.
d.
Issue the show ip protocols command to verify that the router ID changed on
R1.
R1# show
ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 11.11.11.11
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.1.0 0.0.0.255 area 0
192.168.12.0 0.0.0.3 area 0
192.168.13.0 0.0.0.3 area 0
Passive Interface(s):
GigabitEthernet0/1
Routing Information Sources:
Gateway Distance Last Update
33.33.33.33 110 00:00:19
22.22.22.22 110 00:00:31
3.3.3.3 110 00:00:41
2.2.2.2 110 00:00:41
Distance: (default is 110)
e.
Issue the show ip ospf neighbor command on R1 to verify that new router ID for
R2 and R3 is listed.
R1# show
ip ospf neighbor
Neighbor ID Pri
State Dead Time Address Interface
33.33.33.33 0
FULL/ - 00:00:36 192.168.13.2 Serial0/0/1
22.22.22.22 0
FULL/ - 00:00:32 192.168.12.2 Serial0/0/0
Part 4:
Configure OSPF Passive
Interfaces
The passive-interface
command prevents routing updates from being sent through the specified router
interface. This is commonly done to reduce traffic on the LANs as they do not
need to receive dynamic routing protocol communication. In Part 4, you will use
the passive-interface command to
configure a single interface as passive. You will also configure OSPF so that
all interfaces on the router are passive by default, and then enable OSPF
routing advertisements on selected interfaces.
Step 1:
Configure a passive interface.
a.
Issue the show ip ospf interface g0/0 command on R1. Notice the timer
indicating when the next Hello packet is expected. Hello packets are sent every
10 seconds and are used between OSPF routers to verify that their neighbors are
up.
R1# show
ip ospf interface g0/0
GigabitEthernet0/0 is up, line protocol is
up
Internet Address 192.168.1.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 11.11.11.11, Network Type BROADCAST, Cost: 1
Topology-MTID Cost Disabled
Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 11.11.11.11, Interface address 192.168.1.1
No
backup designated router on this network
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)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
b.
Issue the passive-interface command to change the G0/0 interface on R1 to
passive.
R1(config)# router
ospf 1
R1(config-router)# passive-interface g0/0
c.
Re-issue the show ip ospf interface g0/0 command to
verify that G0/0 is now passive.
R1# show
ip ospf interface g0/0
GigabitEthernet0/0 is up, line protocol is
up
Internet Address 192.168.1.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 11.11.11.11, Network Type BROADCAST, Cost: 1
Topology-MTID Cost Disabled
Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 11.11.11.11, Interface address 192.168.1.1
No
backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
No Hellos (Passive interface)
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
d.
Issue the show ip route command on R2 and R3 to verify that a route to the
192.168.1.0/24 network is still available.
R2# show
ip route
Codes: L - local, C - connected, S - static,
R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
2.0.0.0/32 is subnetted, 1 subnets
C
2.2.2.2 is directly connected, Loopback0
O 192.168.1.0/24 [110/65] via
192.168.12.1, 00:58:32, Serial0/0/0
192.168.2.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.2.0/24 is directly connected, GigabitEthernet0/0
L
192.168.2.1/32 is directly connected, GigabitEthernet0/0
O
192.168.3.0/24 [110/65] via 192.168.23.2, 00:58:19, Serial0/0/1
192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.12.0/30 is directly connected, Serial0/0/0
L
192.168.12.2/32 is directly connected, Serial0/0/0
192.168.13.0/30 is subnetted, 1 subnets
O
192.168.13.0 [110/128] via 192.168.23.2, 00:58:19, Serial0/0/1
[110/128] via
192.168.12.1, 00:58:32, Serial0/0/0
192.168.23.0/24 is variably subnetted, 2 subnets, 2 masks
C
192.168.23.0/30 is directly connected, Serial0/0/1
L 192.168.23.1/32 is directly connected,
Serial0/0/1
Step 2:
Set passive interface as the
default on a router.
a.
Issue the show ip ospf neighbor command on R1 to verify that R2 is listed as
an OSPF neighbor.
R1# show
ip ospf neighbor
Neighbor ID Pri
State Dead Time Address Interface
33.33.33.33 0
FULL/ - 00:00:31 192.168.13.2 Serial0/0/1
22.22.22.22 0 FULL/
- 00:00:32 192.168.12.2 Serial0/0/0
b.
Issue the passive-interface default command on R2 to set the default for all
OSPF interfaces as passive.
R2(config)# router
ospf 1
R2(config-router)# passive-interface default
R2(config-router)#
*Apr 3 00:03:00.979:
%OSPF-5-ADJCHG: Process 1, Nbr 11.11.11.11 on Serial0/0/0 from FULL to DOWN,
Neighbor Down: Interface down or detached
*Apr 3 00:03:00.979:
%OSPF-5-ADJCHG: Process 1, Nbr 33.33.33.33 on Serial0/0/1 from FULL to DOWN,
Neighbor Down: Interface down or detached
c.
Re-issue the show ip ospf neighbor command on R1. After
the dead timer expires, R2 will no longer be listed as an OSPF neighbor.
R1# show
ip ospf neighbor
Neighbor ID Pri
State Dead Time Address Interface
33.33.33.33 0
FULL/ - 00:00:34 192.168.13.2 Serial0/0/1
d.
Issue the show ip ospf interface S0/0/0 command on R2 to view the OSPF status
of interface S0/0/0.
R2# show
ip ospf interface s0/0/0
Serial0/0/0 is up, line protocol is up
Internet Address 192.168.12.2/30, Area 0, Attached via Network Statement
Process ID 1, Router ID 22.22.22.22, Network Type POINT_TO_POINT, Cost:
64
Topology-MTID Cost Disabled
Shutdown Topology Name
0 64 no no Base
Transmit Delay is 1 sec, State POINT_TO_POINT
Timer
intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
No Hellos (Passive interface)
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 2/2, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
e.
If all interfaces on R2 are
passive, then no routing information is being advertised. In this case, R1 and
R3 should no longer have a route to the 192.168.2.0/24 network. You can verify
this by using the show ip route
command.
f.
On R2, issue the no passive-interface command so the
router will send and receive OSPF routing updates. After entering this command,
you will see an informational message that a neighbor adjacency has been
established with R1.
R2(config)# router
ospf 1
R2(config-router)# no passive-interface s0/0/0
R2(config-router)#
*Apr 3 00:18:03.463:
%OSPF-5-ADJCHG: Process 1, Nbr 11.11.11.11 on Serial0/0/0 from LOADING to FULL,
Loading Done
g.
Re-issue the show ip route and show ip ospf neighbor commands on R1 and R3, and look for a route
to the 192.168.2.0/24 network.
What interface is R3 using to route to
the 192.168.2.0/24 network? ____________
What is the accumulated cost metric for
the 192.168.2.0/24 network on R3? _________
Does R2 show up as an OSPF neighbor on
R1? ________
Does R2 show up as an OSPF neighbor on
R3? ________
What does this information tell you?
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
h.
Change interface S0/0/1 on R2
to allow it to advertise OSPF routes. Record the commands used below.
____________________________________________________________________________________
____________________________________________________________________________________
i.
Re-issue the show ip route command on R3.
What interface is R3 using to route to
the 192.168.2.0/24 network? ____________
What is the accumulated cost metric for
the 192.168.2.0/24 network on R3 now and how is this calculated?
____________________________________________________________________________________
Is R2 listed as an OSPF neighbor to R3?
________
Part 5:
Change OSPF Metrics
In Part 5, you will change OSPF metrics
using the auto-cost reference-bandwidth
command, the bandwidth command, and
the ip ospf cost command.
Note: All DCE interfaces should have been configured with a clocking
rate of 128000 in Part 1.
Step 1: Change the reference bandwidth on the routers.
The default reference-bandwidth for OSPF
is 100Mb/s (Fast Ethernet speed). However, most modern infrastructure devices
have links that are faster than 100Mb/s. Because the OSPF cost metric must be
an integer, all links with transmission speeds of 100Mb/s or higher have a cost
of 1. This results in Fast Ethernet, Gigabit Ethernet, and 10G Ethernet
interfaces all having the same cost. Therefore, the reference-bandwidth must be
changed to a higher value to accommodate networks with links faster that
100Mb/s.
a.
Issue the show interface command on R1 to view the default bandwidth setting
for the G0/0 interface.
R1# show
interface g0/0
GigabitEthernet0/0 is up, line protocol is
up
Hardware is CN Gigabit
Ethernet, address is c471.fe45.7520 (bia c471.fe45.7520)
MTU
1500 bytes, BW 1000000
Kbit/sec, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive
set (10 sec)
Full Duplex, 100Mbps, media type is RJ45
output flow-control is unsupported, input flow-control is unsupported
ARP
type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:17:31, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5
minute input rate 0 bits/sec, 0 packets/sec
5
minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
279 packets output, 89865 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
1 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
Note: The bandwidth setting on G0/0 may differ from what is shown above
if the PC host interface can only support Fast Ethernet speed. If the PC host
interface is not capable of supporting gigabit speed, then the bandwidth will
most likely be displayed as 100000 Kbit/sec.
b.
Issue the show ip route ospf command on R1 to determine the route to the
192.168.3.0/24 network.
R1# show
ip route ospf
Codes: L - local, C - connected, S -
static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
O
192.168.2.0/24 [110/65] via 192.168.12.2, 00:01:08, Serial0/0/0
O
192.168.3.0/24 [110/65]
via 192.168.13.2, 00:00:57, Serial0/0/1
192.168.23.0/30 is subnetted, 1 subnets
O
192.168.23.0 [110/128] via 192.168.13.2, 00:00:57, Serial0/0/1
[110/128] via
192.168.12.2, 00:01:08, Serial0/0/0
Note: The accumulated cost to the 192.168.3.0/24 network from R1 is 65.
c.
Issue the show ip ospf interface command on R3 to determine the routing cost
for G0/0.
R3# show
ip ospf interface g0/0
GigabitEthernet0/0 is up, line protocol is
up
Internet Address 192.168.3.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 3.3.3.3, Network Type BROADCAST, Cost: 1
Topology-MTID Cost Disabled
Shutdown Topology Name
0 1 no no Base
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 192.168.23.2, Interface address 192.168.3.1
No
backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:05
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
d.
Issue the show ip ospf interface s0/0/1 command on R1 to view the routing
cost for S0/0/1.
R1# show
ip ospf interface s0/0/1
Serial0/0/1 is up, line protocol is up
Internet Address 192.168.13.1/30, Area 0, Attached via Network Statement
Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 64
Topology-MTID Cost Disabled
Shutdown Topology Name
0 64 no no Base
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 00:00:04
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 3/3, 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 192.168.23.2
Suppress hello for 0 neighbor(s)
The sum of the costs of these two
interfaces is the accumulated cost for the route to the 192.168.3.0/24 network
on R3 (1 + 64 = 65), as can be seen in the output from the show ip route command.
e.
Issue the auto-cost reference-bandwidth 10000 command on R1 to change the
default reference bandwidth setting. With this setting, 10Gb/s interfaces will
have a cost of 1, 1 Gb/s interfaces will have a cost of 10, and 100Mb/s
interfaces will have a cost of 100.
R1(config)# router
ospf 1
R1(config-router)# auto-cost reference-bandwidth 10000
% OSPF: Reference bandwidth is changed.
Please ensure reference bandwidth is consistent across all routers.
f.
Issue the auto-cost reference-bandwidth 10000 command on routers R2 and R3.
g.
Re-issue the show ip ospf interface command to view
the new cost of G0/0 on R3, and S0/0/1 on R1.
R3# show
ip ospf interface g0/0
GigabitEthernet0/0 is up, line protocol is
up
Internet Address 192.168.3.1/24, Area 0, Attached via Network Statement
Process ID 1, Router ID 3.3.3.3, Network Type BROADCAST, Cost: 10
Topology-MTID Cost Disabled
Shutdown Topology Name
0 10 no no Base
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 192.168.23.2, Interface address 192.168.3.1
No
backup designated router on this network
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)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
Note: If the device connected to the G0/0 interface does not support
Gigabit Ethernet speed, the cost will be different than the output display. For
example, the cost will be 100 for Fast Ethernet speed (100Mb/s).
R1# show
ip ospf interface s0/0/1
Serial0/0/1 is up, line protocol is up
Internet Address 192.168.13.1/30, Area 0, Attached via Network Statement
Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 6476
Topology-MTID Cost Disabled
Shutdown Topology Name
0 6476
no no Base
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 00:00:05
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 3/3, 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 192.168.23.2
Suppress hello for 0 neighbor(s)
h.
Re-issue the show ip route ospf command to view the
new accumulated cost for the 192.168.3.0/24 route (10 + 6476 = 6486).
Note: If the device connected to the G0/0 interface does not support
Gigabit Ethernet speed, the total cost will be different than the output
display. For example, the accumulated cost will be 6576 if G0/0 is operating at
Fast Ethernet speed (100Mb/s).
R1# show
ip route ospf
Codes: L - local, C - connected, S -
static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
O
192.168.2.0/24 [110/6486]
via 192.168.12.2, 00:05:40, Serial0/0/0
O
192.168.3.0/24 [110/6486]
via 192.168.13.2, 00:01:08, Serial0/0/1
192.168.23.0/30 is subnetted, 1 subnets
O
192.168.23.0 [110/12952] via
192.168.13.2, 00:05:17, Serial0/0/1
[110/12952] via
192.168.12.2, 00:05:17, Serial0/0/
Note: Changing the default reference-bandwidth on the routers from 100
to 10,000 in effect changed the accumulated costs of all routes by a factor of
100, but the cost of each interface link and route is now more accurately
reflected.
i.
To reset the
reference-bandwidth back to its default value, issue the auto-cost reference-bandwidth 100 command on all three routers.
R1(config)# router
ospf 1
R1(config-router)# auto-cost reference-bandwidth 100
% OSPF: Reference bandwidth is changed.
Please ensure reference bandwidth is consistent across all routers.
Why would you want to change the OSPF
default reference-bandwidth?
_______________________________________________________________________________________
_______________________________________________________________________________________
Step 2: Change the bandwidth for an interface.
On most serial links, the bandwidth metric will
default to 1544 Kbits (that of a T1). If this is not the actual speed of the
serial link, the bandwidth setting will need to be changed to match the actual
speed to allow the route cost to be calculated correctly in OSPF. Use the bandwidth command to adjust the bandwidth setting on an interface.
Note: A common misconception is to assume that the bandwidth command will change the physical bandwidth, or speed, of
the link. The command modifies the bandwidth metric used by OSPF to calculate
routing costs, and does not modify the actual bandwidth (speed) of the link.
a.
Issue the show interface s0/0/0 command on R1 to view the current bandwidth
setting on S0/0/0. Even though the clock rate, link speed on this interface was
set to 128Kb/s, the bandwidth is still showing 1544Kb/s.
R1# show
interface s0/0/0
Serial0/0/0 is up, line protocol is up
Hardware is WIC MBRD Serial
Internet address is 192.168.12.1/30
MTU
1500 bytes, BW 1544
Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
<Output omitted>
b.
Issue the show ip route ospf command on R1 to view the accumulated cost for
the route to network 192.168.23.0/24 using S0/0/0. Note that there are two
equal-cost (128) routes to the 192.168.23.0/24 network, one via S0/0/0 and one
via S0/0/1.
R1# show
ip route ospf
Codes: L - local, C - connected, S -
static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
O
192.168.2.0/24 [110/65] via 192.168.12.2, 00:00:26, Serial0/0/0
O
192.168.3.0/24 [110/65] via 192.168.13.2, 00:00:26, Serial0/0/1
192.168.23.0/30
is subnetted, 1 subnets
O
192.168.23.0 [110/128] via 192.168.13.2, 00:00:26, Serial0/0/1
[110/128] via 192.168.12.2,
00:00:26, Serial0/0/0
c.
Issue the bandwidth 128 command to set the bandwidth on S0/0/0 to 128Kb/s.
R1(config)# interface
s0/0/0
R1(config-if)# bandwidth 128
d.
Re-issue the show ip route ospf command. The routing
table no longer displays the route to the 192.168.23.0/24 network over the
S0/0/0 interface. This is because the best route, the one with the lowest cost,
is now via S0/0/1.
R1# show
ip route ospf
Codes: L - local, C - connected, S -
static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
O
192.168.2.0/24 [110/129] via 192.168.12.2, 00:01:47, Serial0/0/0
O
192.168.3.0/24 [110/65] via 192.168.13.2, 00:04:51, Serial0/0/1
192.168.23.0/30 is
subnetted, 1 subnets
O 192.168.23.0 [110/128]
via 192.168.13.2, 00:04:51, Serial0/0/1
e.
Issue the show ip ospf interface brief command. The cost for S0/0/0 has
changed from 64 to 781 which is an accurate cost representation of the link speed.
R1# show
ip ospf interface brief
Interface
PID Area IP Address/Mask Cost
State Nbrs F/C
Se0/0/1
1 0 192.168.13.1/30 64 P2P 1/1
Se0/0/0
1 0 192.168.12.1/30 781 P2P 1/1
Gi0/0
1 0 192.168.1.1/24 1
DR 0/0
f.
Change the bandwidth for
interface S0/0/1 to the same setting as S0/0/0 on R1.
g.
Re-issue the show ip route ospf command to view the
accumulated cost of both routes to the 192.168.23.0/24 network. Note that there
are again two equal-cost (845) routes to the 192.168.23.0/24 network, one via
S0/0/0 and one via S0/0/1.
R1# show
ip route ospf
Codes: L - local, C - connected, S -
static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
O
192.168.2.0/24 [110/782] via 192.168.12.2, 00:00:09, Serial0/0/0
O
192.168.3.0/24 [110/782]
via 192.168.13.2, 00:00:09, Serial0/0/1
192.168.23.0/30
is subnetted, 1 subnets
O
192.168.23.0 [110/845]
via 192.168.13.2, 00:00:09, Serial0/0/1
[110/845] via 192.168.12.2,
00:00:09, Serial0/0/0
Explain how the costs to the
192.168.3.0/24 and 192.168.23.0/30 networks from R1 were calculated.
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
h.
Issue the show ip route ospf command on R3. The accumulated cost of the
192.168.1.0/24 is still showing as 65. Unlike the clock rate command, the bandwidth
command needs to be applied on each side of a serial link.
R3# show
ip route ospf
Codes: L - local, C - connected, S -
static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
O
192.168.1.0/24 [110/65]
via 192.168.13.1, 00:30:58, Serial0/0/0
O
192.168.2.0/24 [110/65] via 192.168.23.1, 00:30:58, Serial0/0/1
192.168.12.0/30 is subnetted, 1 subnets
O
192.168.12.0 [110/128] via 192.168.23.1, 00:30:58, Serial0/0/1
[110/128] via 192.168.13.1, 00:30:58,
Serial0/0/0
i.
Issue the bandwidth 128 command on all remaining serial interfaces in the
topology.
What is the new accumulated cost to the
192.168.23.0/24 network on R1? Why?
____________________________________________________________________________________
____________________________________________________________________________________
Step 3: Change the route cost.
OSPF uses the bandwidth setting to
calculate the cost for a link by default. However, you can override this
calculation by manually setting the cost of a link using the ip ospf cost command. Like the bandwidth
command, the ip ospf cost command
only affects the side of the link where it was applied.
a.
Issue the show ip route ospf on R1.
R1# show
ip route ospf
Codes: L - local, C - connected, S -
static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
O
192.168.2.0/24 [110/782] via 192.168.12.2, 00:00:26, Serial0/0/0
O
192.168.3.0/24 [110/782]
via 192.168.13.2, 00:02:50, Serial0/0/1
192.168.23.0/30 is subnetted, 1 subnets
O
192.168.23.0 [110/1562] via 192.168.13.2, 00:02:40, Serial0/0/1
[110/1562] via
192.168.12.2, 00:02:40, Serial0/0/0
b.
Apply the ip ospf cost 1565 command to the S0/0/1 interface on R1. A cost of
1565 is higher than the accumulated cost of the route through R2 which is 1562.
R1(config)# interface
s0/0/1
R1(config-if)# ip ospf cost 1565
c.
Re-issue the show ip route ospf command on R1 to
display the effect this change has made on the routing table. All OSPF routes
for R1 are now being routed through R2.
R1# show
ip route ospf
Codes: L - local, C - connected, S -
static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
O
192.168.2.0/24 [110/782] via 192.168.12.2, 00:02:06, Serial0/0/0
O
192.168.3.0/24 [110/1563]
via 192.168.12.2, 00:05:31, Serial0/0/0
192.168.23.0/30 is subnetted, 1 subnets
O
192.168.23.0 [110/1562] via 192.168.12.2, 01:14:02, Serial0/0/0
Note: Manipulating link costs using the ip ospf cost command is the easiest and preferred method for
changing OSPF route costs. In addition to changing the cost based on bandwidth,
a network administrator may have other reasons for changing the cost of a route,
such as preference for a particular service provider or the actual monetary
cost of a link or route.
Explain why the route to the
192.168.3.0/24 network on R1 is now going through R2?
_______________________________________________________________________________________
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Reflection
1.
Why is it important to control
the router ID assignment when using the OSPF protocol?
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2.
Why is the DR/BDR election
process not a concern in this lab?
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3.
Why would you want to set an
OSPF interface to passive?
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Router Interface Summary Table
|
Router Interface Summary
|
||||
|
Router Model
|
Ethernet Interface #1
|
Ethernet Interface #2
|
Serial Interface #1
|
Serial Interface #2
|
|
1800
|
Fast Ethernet 0/0 (F0/0)
|
Fast Ethernet 0/1 (F0/1)
|
Serial 0/0/0 (S0/0/0)
|
Serial 0/0/1 (S0/0/1)
|
|
1900
|
Gigabit Ethernet 0/0 (G0/0)
|
Gigabit Ethernet 0/1 (G0/1)
|
Serial 0/0/0 (S0/0/0)
|
Serial 0/0/1 (S0/0/1)
|
|
2801
|
Fast Ethernet 0/0 (F0/0)
|
Fast Ethernet 0/1 (F0/1)
|
Serial 0/1/0 (S0/1/0)
|
Serial 0/1/1 (S0/1/1)
|
|
2811
|
Fast Ethernet 0/0 (F0/0)
|
Fast Ethernet 0/1 (F0/1)
|
Serial 0/0/0 (S0/0/0)
|
Serial 0/0/1 (S0/0/1)
|
|
2900
|
Gigabit Ethernet 0/0 (G0/0)
|
Gigabit Ethernet 0/1 (G0/1)
|
Serial 0/0/0 (S0/0/0)
|
Serial 0/0/1 (S0/0/1)
|
|
Note: To find out how the router is configured, look at the interfaces
to identify the type of router and how many interfaces the router has. There
is no way to effectively list all the combinations of configurations for each
router class. This table includes identifiers for the possible combinations
of Ethernet and Serial interfaces in the device. The table does not include
any other type of interface, even though a specific router may contain one.
An example of this might be an ISDN BRI interface. The string in parenthesis
is the legal abbreviation that can be used in Cisco IOS commands to represent
the interface.
|
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