Quagga OSPF Simulation in CentOS 6

Scenario

This article is actually a modified version of a previous article

IP Details

All the Routers in the diagram are actually CentOS 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:~# yum install quagga


We would be configuring the interface parameters. Keep in mind, there are example configuration files stored in /usr/share/doc/quagga/

root@alpha:~# cd /etc/quagga
root@alpha:/etc/quagga# cat zebra.conf.sample > zebra.conf
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# cat ospf.conf.sample > ospf.conf


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/zebra restart
root@alpha:/etc/quagga# /etc/init.d/ospfd restart
root@alpha:/etc/quagga# chkconfig zebra on
root@alpha:/etc/quagga# chkconfig ospfd on


vtyshprovides a shell that resembles the CISCO IOS shell. It even supports commands from the CISCO IOS.


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.

Here is a sample output of quagga log from one of my Quagga Routers.

[root@firefly ~]# tail -f /var/log/quagga/ospfd.log
 
2012/04/15 15:13:53 OSPF: DR-Election[1st]: DR     192.168.1.2
2012/04/15 15:13:53 OSPF: DR-Election[2nd]: Backup 192.168.1.3
2012/04/15 15:13:53 OSPF: DR-Election[2nd]: DR     192.168.1.2
2012/04/15 15:13:53 OSPF: ospfTrapIfStateChange trap sent: 192.168.1.3 now Backup
2012/04/15 15:13:53 OSPF: interface 192.168.1.3 [3] join AllDRouters Multicast group.
2012/04/15 15:13:53 OSPF: DR-Election[1st]: Backup 192.168.1.3
2012/04/15 15:13:53 OSPF: DR-Election[1st]: DR     192.168.1.2
2012/04/15 15:13:53 OSPF: Packet[DD]: Neighbor 10.0.0.1: Initial DBD from Slave, ignoring.
2012/04/15 15:13:53 OSPF: Packet[DD]: Neighbor 10.0.0.1 Negotiation done (Master).
2012/04/15 15:13:53 OSPF: nsm_change_state(10.0.0.1, Loading -> Full): scheduling new router-LSA origination
 

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/zebra restart
root@beta:/etc/quagga# /etc/init.d/ospfd restart
root@beta:/etc/quagga# chkconfig zebra on
root@beta:/etc/quagga# chkconfig ospfd on

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@gamma:/etc/quagga# /etc/init.d/zebra restart
root@gamma:/etc/quagga# /etc/init.d/ospfd restart
root@gamma:/etc/quagga# chkconfig zebra on
root@gamma:/etc/quagga# chkconfig ospfd on

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.