1. OSPF in Multiple Area

2. Issues in Single area OSPF
As the size of the network increases there will be large number of LSAs flooded in the network, which is a overhead to the Routers.
The routing table will become extremely large.

3. Advantage of Multiple-Area
Extensive control of routing updates.
Defining areas reduce routing overhead.
Speedup convergence.
Confines network instability to one area.
Improves performance.

4. OSPF - Network Diagram HYD CHE BAN Area 1 Area 2 Area 0 10.0.0.1/8 S0/8 S0
HYD S1 /8
CHE S1 /8
BAN E0
/24 E0
/24 E0
/24
Area 0
LAN /24
LAN – /24
LAN /24

6. Directly Connected Networks on HYDERABAD Router
Microsoft Windows 2000 [Version ]
(C) Copyright Microsoft Corp.
C:\>
telnet
Connecting
.....
================================
Welcome to Hyderabad Router
User Access Verification
password :
****
Directly Connected Networks on HYDERABAD Router
Hyderabad>
enable
password :
****
Hyderabad#
configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Hyderabad(config)#
interface serial 0
Hyderabad(config-if)#
ip address
Hyderabad(config-if)#
no shut
Hyderabad(config-if)#
clockrate 64000
Hyderabad(config-if)#
encapsulation hdlc
Hyderabad(config-if)#
exit
Hyderabad(config)#

7. Hyderabad(config)#
no ip routing
Hyderabad(config)#
ip routing
Hyderabad(config)#
router ospf 1
Hyderabad(config-router)#
network area 1
Hyderabad(config-router)#
network area 1
Configuring OSPF
Router(config)# router ospf <pid>
Router(config-router)# network <Network ID> <wildcard mask> area <area id>
Hyderabad(config-router)#

8. 110 is nothing but Administrative Distance
Hyderabad(config)#
router ospf 1
Hyderabad(config-router)#
network area 1
network area 1
no ip routing
ip routing ^Z
Hyderabad#
show ip route
Codes: C - connected, S - static, I - IGRP, 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,*- candidate default
U - per-user static route, o - ODR
Gateway of last resort is not set
C /8 is directly connected, Serial0
O IA /8 [110/128] via , 00:01:03, Serial0
C /24 is directly connected, Ethernet0
O IA /24 [110/74] via , 00:01:03, Serial0
O IA /24 [110/138] via , 00:00:13, Serial0
Hyderabad#
O IA – for OSPF
Inter Area routes
110 is nothing but Administrative Distance
Metric of OSPF
Cost

9. Neighbor ID Pri State Dead Time Address
Hyderabad#
show ip ospf database
OSPF Router with ID ( ) (Process ID 1)
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link x xA
x xBACC 2
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
x xDA15
x x8441
x xFB88
Hyderabad#
show ip ospf neighbor
Neighbor ID Pri State Dead Time Address
FULL/ :00:
Hyderabad#

10. Directly Connected Networks on CHENNAI Router
Microsoft Windows 2000 [Version ]
(C) Copyright Microsoft Corp.
C:\>
telnet
Connecting
.....
================================
Welcome to Chennai Router
User Access Verification
password :
****
Directly Connected Networks on CHENNAI Router
Chennai>
enable
password :
****
Chennai#
configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Chennai(config)#
interface serial 1
Chennai(config-if)#
ip address
Chennai(config-if)#
no shut
Chennai(config-if)#
encapsulation hdlc
Chennai(config-if)#
interface serial 0
Chennai(config-if)#
ip address
Chennai(config-if)#
no shut
Chennai(config-if)#
encapsulation hdlc

11. Chennai(config)#
no ip routing
Chennai(config)#
ip routing
Chennai(config)#
router ospf 2
Chennai(config-router)#
network area 0
Chennai(config-router)#
network area 1
Configuring OSPF
Router(config)# router ospf <pid>
Router(config-router)# network <Network ID> <wildcard mask> area <area id>
Chennai(config-router)#
network area 2
Chennai(config-router)#

12. 110 is nothing but Administrative Distance
Chennai(config)#
router ospf 2
Chennai(config-router)#
network area 0
network area 1
no ip routing
ip routing
network area 2 ^Z
Chennai#
show ip route
Codes: C - connected, S - static, I - IGRP, 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,*- candidate default
U - per-user static route, o - ODR
Gateway of last resort is not set
C /8 is directly connected, Serial1
C /8 is directly connected, Serial0
O /24 [110/74] via , 00:01:04, Serial1
C /24 is directly connected, Ethernet0
O /24 [110/74] via , 00:00:09, Serial0
Chennai#
O – for OSPF routes
110 is nothing but Administrative Distance
Metric of OSPF
Cost

13. Chennai# show ip ospf database
OSPF Router with ID ( ) (Process ID 2)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link x xEFC7 1
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
x xE709
x xDA15
x x1274
x xFB88
Router Link States (Area 1)
Link ID ADV Router Age Seq# Checksum Link x xA
x xBACC 2
--More—-

14. Neighbor ID Pri State Dead Time Address
Summary Net Link States (Area 1)
Link ID ADV Router Age Seq# Checksum
x xDA15
x x8441
x xFB88
Router Link States (Area 2)
Link ID ADV Router Age Seq# Checksum Link x xDAA8 2
x xD
Summary Net Link States (Area 2)
x xE709
x x1274
x x8441
Chennai#
show ip ospf neighbor
Neighbor ID Pri State Dead Time Address
FULL/ :00:
FULL/ :00:
Chennai#

15. Directly Connected Networks on Banglore Router
Microsoft Windows 2000 [Version ]
(C) Copyright Microsoft Corp.
C:\>
telnet
Connecting
.....
================================
Welcome to Banglore Router
User Access Verification
password :
****
Directly Connected Networks on Banglore Router
Banglore>
enable
password :
****
Banglore#
configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Banglore(config)#
interface serial 1
Banglore(config-if)#
ip address
Banglore(config-if)#
no shut
Banglore(config-if)#
clockrate 64000
Banglore(config-if)#
encapsulation hdlc
Banglore(config-if)#
exit
Banglore(config)#

16. Banglore(config)#
no ip routing
Banglore(config)#
ip routing
Banglore(config)#
router ospf 1
Banglore(config-router)#
network area 2
Banglore(config-router)#
network area 2
Configuring OSPF
Router(config)# router ospf <pid>
Router(config-router)# network <Network ID> <wildcard mask> area <area id>
Banglore(config-router)#

17. 110 is nothing but Administrative Distance
Banglore(config)#
router ospf 1
Banglore(config-router)#
network area 2
no ip routing
ip routing
network area 2 ^Z
Banglore#
show ip route
Codes: C - connected, S - static, I - IGRP, 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,*- candidate default
U - per-user static route, o - ODR
Gateway of last resort is not set
O IA /8 [110/128] via , 00:02:26, Serial1
C /8 is directly connected, Serial1
O IA /24 [110/138] via , 00:02:26, Serial1
O IA /24 [110/74] via , 00:02:26, Serial1
C /24 is directly connected, Ethernet0
Banglore#
O IA – for OSPF
Inter Area routes
110 is nothing but Administrative Distance
Metric of OSPF
Cost

18. Neighbor ID Pri State Dead Time Address
Banglore#
show ip ospf database
OSPF Router with ID ( ) (Process ID 1)
Router Link States (Area 2)
Link ID ADV Router Age Seq# Checksum Link x xDAA8 2
x xD
Summary Net Link States (Area 2)
Link ID ADV Router Age Seq# Checksum
x xE709
x x1274
x x8441
Banglore#
show ip ospf neighbor
Neighbor ID Pri State Dead Time Address
FULL/ :00:
Banglore#

19. Type escape sequence to abort.
Hyderabad#
ping
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 40/43/44 ms
Hyderabad#
ping
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 40/43/44 ms
Hyderabad#

20. Type escape sequence to abort.
Chennai#
ping
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 40/43/44 ms
Chennai#
ping
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 40/43/44 ms
Chennai#

21. Type escape sequence to abort.
Banglore#
ping
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 40/43/44 ms
Banglore#
ping
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 40/43/44 ms
Banglore#