OSPF (Open
Shortest Path First)
-
“Link
state”
-
Developed
by ISO
-
Advertise
Interface Status instead of send all of routing table in “Distance Vector”
-
Can
see all of topology
-
Use
SPF (Shortest Path First) Algorithm or Dijkstra’s Algorithm
-
Periodic
update every 30 minute
-
Hello
mechanism
-
Using
Bandwidth
-
Support
VLSM
-
OSPF
Area, route Authentication
-
Fast
Convergence
“Cost =
10^8/Bandwidth(bps)”
Ex.
Bandwidth 100Mbps = 10^8/100*10^6 = 1
Calculate
from interface-based and outgoing direction
-
If
topology has only a area, we can use other number
-
Area0
is called “Backbone Area”
-
If
you want to communicate between a Area to another area you must pass packet by
Area0
Router
in OSPF
1)
Backbone Router – Work in Area0
2)
Area Border Router (ABR) – Have least
a interface that connect with Area0 and have one connect with another area
3)
Autonomous System Border Router (ASBR) –
Connect with another autonomous system or distinct protocols
4)
Internal Router – Within on area (no have
interface connect with other area)
OSPF
Routing Entry
1)
Intra-Area
Routing – Calculate from SPF Algorithm inside area (“O”)
2)
Inter-Area
Routing – Routing that have routing entry to distinct subnet address Area (“O
IA”)
3)
External
Routes – Connect to other subnet address (“E1,E2”)
Configuration
R1#show
run
Building
configuration...
Current
configuration : 548 bytes
!
version
12.4
no
service timestamps log datetime msec
no
service timestamps debug datetime msec
no
service password-encryption
!
hostname
R1
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface
FastEthernet0/0
bandwidth 10000
ip address 10.15.0.1 255.255.255.0
duplex auto
speed auto
!
interface
FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface
Vlan1
no ip address
shutdown
!
router
ospf 1
log-adjacency-changes
network 10.15.0.1 0.0.0.0 area 15
!
ip
classless
!
!
!
!
!
!
!
line
con 0
line
vty 0 4
login
!
!
!
end
R5#show
run
Building
configuration...
Current
configuration : 642 bytes
!
version
12.4
no
service timestamps log datetime msec
no
service timestamps debug datetime msec
no
service password-encryption
!
hostname
R5
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface
FastEthernet0/0
bandwidth 10000
ip address 10.15.0.5 255.255.255.0
duplex auto
speed auto
!
interface
FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface
Serial0/0/0
ip address 10.45.0.5 255.255.255.0
!
interface
Vlan1
no ip address
shutdown
!
router
ospf 1
log-adjacency-changes
network 10.45.0.5 0.0.0.0 area 0
network 10.15.0.5 0.0.0.0 area 15
!
ip
classless
!
!
!
!
!
!
!
line
con 0
line
vty 0 4
login
!
!
!
End
R4#show
run
Building
configuration...
Current
configuration : 911 bytes
!
version
12.4
no
service timestamps log datetime msec
no
service timestamps debug datetime msec
no
service password-encryption
!
hostname
R4
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface
FastEthernet0/0
no ip address
duplex auto
speed auto
shutdown
!
interface
FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface
Serial0/0/0
bandwidth 128
ip address 10.34.0.4 255.255.255.0
clock rate 9600
!
interface
Serial0/0/1
bandwidth 64
ip address 10.43.0.4 255.255.255.0
clock rate 9600
!
interface
Serial0/1/0
no ip address
shutdown
!
interface
Serial0/1/1
bandwidth 128
ip address 10.45.0.4 255.255.255.0
clock rate 9600
!
interface
Vlan1
no ip address
shutdown
!
router
ospf 1
log-adjacency-changes
network 10.34.0.4 0.0.0.0 area 0
network 10.43.0.4 0.0.0.0 area 0
network 10.45.0.4 0.0.0.0 area 0
!
ip
classless
!
!
!
!
!
!
!
line
con 0
line
vty 0 4
login
!
!
!
End
R3#show
run
Building
configuration...
Current
configuration : 748 bytes
!
version
12.4
no
service timestamps log datetime msec
no
service timestamps debug datetime msec
no
service password-encryption
!
hostname
R3
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface
FastEthernet0/0
ip address 10.36.0.3 255.255.255.0
duplex auto
speed auto
!
interface
FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface
Serial0/0/0
bandwidth 128
ip address 10.34.0.3 255.255.255.0
!
interface
Serial0/0/1
bandwidth 64
ip address 10.43.0.3 255.255.255.0
!
interface
Vlan1
no ip address
shutdown
!
router
ospf 1
log-adjacency-changes
network 10.34.0.3 0.0.0.0 area 0
network 10.43.0.3 0.0.0.0 area 0
network 10.36.0.3 0.0.0.0 area 36
!
ip
classless
!
!
!
!
!
!
!
line
con 0
line
vty 0 4
login
!
!
!
End
R6#show
run
Building
configuration...
Current
configuration : 531 bytes
!
version
12.4
no
service timestamps log datetime msec
no
service timestamps debug datetime msec
no
service password-encryption
!
hostname
R6
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface
FastEthernet0/0
ip address 10.36.0.6 255.255.255.0
duplex auto
speed auto
!
interface
FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface
Vlan1
no ip address
shutdown
!
router
ospf 1
log-adjacency-changes
network 10.36.0.6 0.0.0.0 area 36
!
ip
classless
!
!
!
!
!
!
!
line
con 0
line
vty 0 4
login
!
!
!
end
