OSPF Simulation using Quagga

Scenario

 

IP Details

All the Routers in the diagram are actually Debian Machines.

Router Alpha:

• eth0: 192.168.10.254/24
  
• eth1: 10.0.0.2/30
  

Router Beta:

• eth0: 192.168.20.254/24
• eth1: 10.0.0.1/30
• eth2: 10.0.0.5/30

Router Gamma:

• eth0: 192.168.30.254/24
• eth1: 10.0.0.6/30

Objective

We would be configuring the Linux boxes with dynamic routing protocol OSPF for total connectivity. This would be done with the help of Quagga.

Router Alpha Configuration

root@alpha:~# apt-get install quagga


First, we have to enable the routing protocols needed.
root@alpha:~# cd /etc/quagga/
root@alpha:~# vim daemons

zebra=yes

bgpd=no

ospfd=yes

ospf6d=no

ripd=no

ripngd=no

isisd=no

Next, we would be configuring the interface parameters. Keep in mind, there are example configuration files stored in /usr/share/doc/quagga/examples.
root@alpha:/etc/quagga# vim zebra.conf

hostname AplhaRouter

password zebra

enable password zebra

!

! Interface's description.

!

interface lo

description loopback

ip address 127.0.0.1/8

ip forwarding 

interface eth0

description LAN

ip address 192.168.10.254/24

ip forwarding

interface eth1

description to_beta

ip address 10.0.0.2/30

ip forwarding

log file /var/log/quagga/zebra.log

Now to the OSPF Configuration.


root@alpha:/etc/quagga# vim ospfd.conf

### we define the interfaces that take part in OSPF

interface eth0

interface eth1

router ospf

network 10.0.0.0/30 area 0

network 192.168.10.0/24 area 0

log stdout

log file /var/log/quagga/ospfd.log

Now, it's time to start the Quagga daemon. We do this by-


root@alpha:/etc/quagga# /etc/init.d/quagga restart


vtyshprovides a shell that resembles the CISCO IOS shell. It even supports commands from the CISCO IOS. If vtysh.conf is not already present, we copy the file from /usr.

root@alpha:~# cp /usr/share/doc/quagga/examples/vtysh.conf.sample /etc/quagga/vtysh.conf
root@alpha:~#vtysh

Hello, this is Quagga (version 0.99.17).
Copyright 1996-2005 Kunihiro Ishiguro, et al.


AlphaRouter# show ip route
Codes: K - kernel route, C - connected, S - static, R - RIP, O - OSPF,
I - ISIS, B - BGP, > - selected route, * - FIB route

C>* 127.0.0.0/8 is directly connected, lo
C>* 10.0.0.2/30 is directly connected, eth0
C>* 192.168.10.0/24 is directly connected, eth1
AlphaRouter# exit


We can issue commands like show ip route or show ip ospf in vtysh to check the available routes and OSPF status. However, since there are no OSPF neighbors yet, theshow ip route should show only directly connected devices.

Router Beta Configuration

Time to configure the next Linux box. The configuration is identical except for the network parameters. Here it goes -
root@beta:/etc/quagga# cat zebra.conf

hostname BetaRouter

password zebra

enable password zebra

!

! Interface's description.

!

interface lo

description loopback

ip address 127.0.0.1/8

ip forwarding

interface eth0

description LAN

ip address 192.168.20.254/24

ip forwarding

interface eth1

description to_alpha

ip address 10.0.0.1/30

ip forwarding

interface eth2

description to_gamma

ip address 10.0.0.5/30

ip forwarding

log file /var/log/quagga/zebra.log

root@beta:/etc/quagga# cat ospfd.conf

### we define the interfaces that take part in OSPF

interface eth0

interface eth1

interface eth2

router ospf

network 10.0.0.0/30 area 0

network 10.0.0.4/30 area 0

network 192.168.20.0/24 area 0

log stdout

log file /var/log/quagga/ospfd.log

Time to start the Quagga daemon again.

root@beta:/etc/quagga# /etc/init.d/quagga restart

root@beta:~#vtysh
Hello, this is Quagga (version 0.99.17).
Copyright 1996-2005 Kunihiro Ishiguro, et al.


BetaRouter# show ip route
Codes: K - kernel route, C - connected, S - static, R - RIP, O - OSPF, I - ISIS, B - BGP, > - selected route, * - FIB route

C>* 127.0.0.0/8 is directly connected, lo
O 10.0.0.1/30 [110/20] is directly connected, eth1
C>* 10.0.0.1/30 is directly connected, eth1
O 10.0.0.5/30 [110/20] is directly connected, eth2
C>* 10.0.0.5/30 is directly connected, eth2
O>* 192.168.10.0/24 [110/40] via 10.0.0.2, eth1,
O 192.168.20.0/24 [110/20] is directly connected, eth0
C>* 192.168.20.0/24 is directly connected, eth0


BetaRouter# exit

As we can see now, the neighbor relationship has been formed and Alpha and beta have already exchanged routing information.

Now try pinging between the Alpha and Beta networks. Should work. Alternatively, also using the good old routecommand as well to see whether the routes are already being learnt. 

Router Gamma Configuration

The configuration of Gamma is same as the previous Linux boxes.


root@gamma:/etc/quagga# cat zebra.conf

hostname GammaRouter

password zebra

enable password zebra

!

! Interface's description.

!

interface lo

description loopback

ip address 127.0.0.1/8

ip forwarding

interface eth0

description LAN

ip address 192.168.30.254/24

ip forwarding

interface eth1

description to_beta

ip address 10.0.0.6/30

ip forwarding

log file /var/log/quagga/zebra.log

root@gamma:/etc/quagga# cat ospfd.conf

### we define the interfaces that take part in OSPF

interface eth0

interface eth1

router ospf

network 10.0.0.4/30 area 0

network 192.168.30.0/24 area 0

log stdout

log file /var/log/quagga/ospfd.log

Time to start the Quagga daemon again.


root@alpha:/etc/quagga# /etc/init.d/quagga restart

The system is now ready to rumble. Try viewing the routes by route or ip route or show ip route (vtysh). All the routers should be able to ping each other, and each host from any of the LANs should be able to communicate with host of other LAN. Again, traceroutecan also be used to check the path that is being taken by a packet.

Hope it helps.