OSPF

OSPF (Open Shortest path first)
 It use when all Routers are not a cisco Routers.

Features of  OSPF

• AD(Administrative Distance) is 110.
• It consist of area and process Id
• It support VLSM/CIDR.
• It has Minimum Routing update traffic.
• It has unlimited Hop-Count.
• No Auto-summary by default.
• classless support.
• It is Link State Routing Protocol.
• Path matric is Bandwidth.
• Convergence is very fast.

 OSPF DR and BDR Elections
DR(Designated Route) and BDR(Back up Designated Route) is accomplished via the hello protocol.
Hello packets are exchange via ip multicast packets on each segments.

R1 Interface Setup

hostname R1
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
ip cef
!
!
!
!
no ip domain lookup
!
multilink bundle-name authenticated
!
archive
 log config
  hidekeys
!
!
!
!
ip tcp synwait-time 5
ip ssh version 1
!
!
!
!
interface FastEthernet0/0
 ip address 192.168.50.10 255.255.255.0
 duplex auto
 speed auto
!
interface FastEthernet0/1
 ip address 192.168.0.1 255.255.255.0
 duplex auto
 speed auto
!
router ospf 1
 log-adjacency-changes
 passive-interface FastEthernet0/1
 network 192.168.0.0 0.0.0.255 area 0
 network 192.168.50.0 0.0.0.255 area 0
!
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
!
no cdp log mismatch duplex
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line vty 0 4
 login
!
!
end

R2 Interface Setup

hostname R2
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
ip cef
!
!
!
!
no ip domain lookup
!
multilink bundle-name authenticated
!
!
!
archive
 log config
  hidekeys
!
!
!
!
ip tcp synwait-time 5
ip ssh version 1
!
!
!
!
interface FastEthernet0/0
 ip address 192.168.50.3 255.255.255.0
 duplex auto
 speed auto
!
interface FastEthernet0/1
 ip address 192.168.3.1 255.255.255.0
 duplex auto
 speed auto
!
router ospf 1
 log-adjacency-changes
 passive-interface FastEthernet0/1
 network 192.168.3.0 0.0.0.255 area 0
 network 192.168.50.0 0.0.0.255 area 0
!
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
!
no cdp log mismatch duplex
!
!
!
!
!
!
control-plane
!
!
!
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line vty 0 4
 login
!
!
end

R3 Interface Setup

hostname R3
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
ip cef
!
!
!
no ip domain lookup
!
multilink bundle-name authenticated
!
!
!
archive
 log config
  hidekeys
!
!
!
!
ip tcp synwait-time 5
ip ssh version 1
!
!
!
!
interface FastEthernet0/0
 ip address 192.168.50.2 255.255.255.0
 duplex auto
 speed auto
!
interface FastEthernet0/1
 ip address 192.168.2.1 255.255.255.0
 duplex auto
 speed auto
!
router ospf 1
 log-adjacency-changes
 passive-interface FastEthernet0/1
 network 192.168.2.0 0.0.0.255 area 0
 network 192.168.50.0 0.0.0.255 area 0
!
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
!
no cdp log mismatch duplex
!
!
control-plane
!
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line vty 0 4
 login
!
!
end

R4 Interface Setup

hostname R4
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
ip cef
!
!
!
!
no ip domain lookup
!
multilink bundle-name authenticated
!
!
!
archive
 log config
  hidekeys
!
!
!
!
ip tcp synwait-time 5
ip ssh version 1
!
!
!
!
interface FastEthernet0/0
 ip address 192.168.50.1 255.255.255.0
 duplex auto
 speed auto
!
interface FastEthernet0/1
 ip address 192.168.1.1 255.255.255.0
 duplex auto
 speed auto
!
interface Serial1/0
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/1
 ip address 200.10.10.253 255.255.255.252
 serial restart-delay 0
!
interface Serial1/2
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/3
 no ip address
 shutdown
 serial restart-delay 0
!
router ospf 1
 log-adjacency-changes
 passive-interface FastEthernet0/1
 passive-interface Serial1/1
 network 192.168.1.0 0.0.0.255 area 0
 network 192.168.50.0 0.0.0.255 area 0
 default-information originate
!
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 Serial1/1
ip route 200.10.10.248 255.255.255.252 200.10.10.254
!
!
no ip http server
no ip http secure-server
!
no cdp log mismatch duplex
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
!
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line vty 0 4
 login
!
!
end

ISP Interface Setup

hostname ISP
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
ip cef
!
!
!
!
no ip domain lookup
!
multilink bundle-name authenticated
!
!
!
!
!
!
archive
 log config
  hidekeys
!
!
!
!
ip tcp synwait-time 5
ip ssh version 1
!
!
!
!
interface Loopback0
 ip address 200.10.10.249 255.255.255.252
!
interface FastEthernet0/0
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial1/0
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/1
 ip address 200.10.10.254 255.255.255.252
 serial restart-delay 0
!
interface Serial1/2
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/3
 no ip address
 shutdown
 serial restart-delay 0
!
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 Loopback0
ip route 192.168.0.0 255.255.192.0 Serial1/1
!
!
no ip http server
no ip http secure-server
!
no cdp log mismatch duplex
!
!
!
control-plane
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
line vty 0 4
 login
!
!
end

DR and BDR Elections

R2#show ip ospf neighbor
Neighbor ID     Pri   State           Dead Time   Address         Interface
192.168.50.2      1   2WAY/DROTHER    00:00:34    192.168.50.2    FastEthernet0/0
192.168.50.10     1   FULL/DR         00:00:33    192.168.50.10   FastEthernet0/0
200.10.10.253     1   FULL/BDR        00:00:32    192.168.50.1    FastEthernet0/0