niab ospf tutorial lab

Lab diagram

Lab aim

This is the second of five labs that make up the niab tutorial. To complete
the tutorial, it is recommended that you follow the lab-guides in this order.
demo-lab-guide: Introduction to using niab.
ospf-lab-guide: OSPF tutorial. << You are here !
bgp-lab-guide: BGP tutorial.
ent1-lab-guide: DNS, email, web tutorial.
isp1-lab-guide: Use external lab connections.

Covers the configuration and support of the OSPF routing protocol.

Lab overview

Lab instructions

1) Restore the lab
We perform the same steps as described in the 'demo' tutorial.

- start the lab
[ncarter:~/niab-labs/ospf]>niab start
[ncarter:~/niab-labs/ospf]>

- wait for nodes to boot (tail log/*.log file to view boot progress)

- restore the lab configuration
Only attempt this once all the nodes are fully booted.
[ncarter:~/niab-labs/ospf]>niab restore
niab: node 'r01' config restored from ./node-configs/r01
niab: node 'r02' config restored from ./node-configs/r02
niab: node 'r03' config restored from ./node-configs/r03
niab: node 'r04' config restored from ./node-configs/r04
niab: node 'r05' config restored from ./node-configs/r05
niab: node 'r06' config restored from ./node-configs/r06
niab: node 'r07' config restored from ./node-configs/r07
niab: node 'r08' config restored from ./node-configs/r08
[ncarter:~/niab-labs/ospf]>

- stop the lab
[ncarter:~/niab-labs/ospf]>niab stop
[ncarter:~/niab-labs/ospf]>

- wait for nodes to stop

- start the lab
Only attempt this once all nodes have stopped.
[ncarter:~/niab-labs/ospf]>niab start
[ncarter:~/niab-labs/ospf]>

- wait for nodes to boot (tail *.log file to view boot progress)

2) Connect to node r01, and log in as user root.
If you are running X-Windows:
[ncarter:~/niab-labs/ospf]>niab term r01
[ncarter:~/niab-labs/ospf]>
An xterm connected to r01, displaying a login prompt, will appear.

If you are not running X-Windows:
- use 'niab nodes' command to find out which tcp port is bound to r01
- telnet to the tcp port

3) Check connectivity
All routers in this lab should be able to ping each other.
- ping each remote router r02 - r08
r01:~# ping -c 2 r02
PING r02 (10.128.16.2): 56 data bytes
64 bytes from 10.128.16.2: icmp_seq=0 ttl=64 time=6.8 ms
64 bytes from 10.128.16.2: icmp_seq=1 ttl=64 time=1.9 ms

--- r02 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 1.9/4.3/6.8 ms
r01:~#

Repeat for r03 - r08

If any of these pings fail then its time to start troubleshooting.

4) View r01 OSPF configuration
r01:~# telnet localhost ospfd
Password: zebra
r01-ospfd> enable
Password: zebra
r01-ospfd# sh run
...
router ospf
ospf router-id 10.128.16.1     << router-id is set to dummy0 address
passive-interface dummy0       << do not send hello packets out of dummy0
network 10.128.16.1/32 area 0 << dummy0 interface is part of area 0
network 10.128.18.0/29 area 0 << 2 x core links are part of area 0
network 10.128.18.8/29 area 0
network 10.128.20.0/29 area 1 << Link to area 1 is part of area 1
area 1 range 10.128.20.0/23    << Summarise area1 address range
...
r01-ospfd#

5) View r01 hello packets
- turn on terminal monitoring (console messages are now also copied to this
terminal)
r01-ospfd# term monitor
- turn on ospf hello debug
r01-ospfd# debug ospf packet hello
... ospf hello packets sent / received between r01 and r02 ...
2004/06/16 10:35:15 OSPF: Hello received from [10.128.16.2] via
[eth0:10.128.18.1]
2004/06/16 10:35:15 OSPF: src [10.128.18.2],
2004/06/16 10:35:15 OSPF: dst [224.0.0.5]
2004/06/16 10:35:17 OSPF: Hello sent to [224.0.0.5] via [eth0:10.128.18.1].
....

- turn off ospf hello debug
r01-ospfd# no deb ospf packet hello

6) View Router LSA for r02
r01-ospfd# sh ip ospf database router adv-router 10.128.16.2
...
                Router Link States (Area (0.0.0.0))

LS age: 1490 << Age of LSA, will eventually trigger LSA refresh
Options: 2
Flags: 0x1 : ABR
LS Type: router-LSA
Link State ID: 10.128.16.2
Advertising Router: 10.128.16.2
LS Seq Number: 80000004 << No change if network is stable (until timeout)
Checksum: 0xcad8
Length: 60
   Number of Links: 3

    Link connected to: Stub Network                << Stub as this is dummy0
     (Link ID) Network/subnet number: 10.128.16.2
     (Link Data) Network Mask: 255.255.255.255
      Number of TOS metrics: 0
       TOS 0 Metric: 10 << metric for this link is 10 (default)

    Link connected to: a Transit Network
     (Link ID) Designated Router address: 10.128.18.2   << r02 is DR
     (Link Data) Router Interface address: 10.128.18.2 <<
      Number of TOS metrics: 0
       TOS 0 Metric: 10

    Link connected to: a Transit Network
     (Link ID) Designated Router address: 10.128.18.18 << r04 is DR
     (Link Data) Router Interface address: 10.128.18.17 <<
      Number of TOS metrics: 0
       TOS 0 Metric: 10

7) View summary LSA for r08 dummy0
r01-ospfd# sh ip ospf database summary 10.128.16.8
       OSPF Router with ID (10.128.16.1)
                Summary Link States (Area (0.0.0.0))

LS age: 457
Options: 2
LS Type: summary-LSA
Link State ID: 10.128.16.8 (summary Network Number) << r08 dummy0
Advertising Router: 10.128.16.2   << r02 is summarising into area0
LS Seq Number: 80000002
Checksum: 0x32cc
Length: 28
Network Mask: /32    << dummy addresses are configured as /32 host address
        TOS: 0 Metric: 30
LS age: 242
Options: 2
LS Type: summary-LSA
Link State ID: 10.128.16.8 (summary Network Number)
Advertising Router: 10.128.16.4   << r04 is summarising into area0
LS Seq Number: 80000002
Checksum: 0x26d6
Length: 28
Network Mask: /32
        TOS: 0 Metric: 30

                Summary Link States (Area (0.0.0.1))

LS age: 258
Options: 2
LS Type: summary-LSA
Link State ID: 10.128.16.8 (summary Network Number)
Advertising Router: 10.128.16.1 << r01 is summarising into area1
LS Seq Number: 80000002
Checksum: 0x9c59
Length: 28
Network Mask: /32
        TOS: 0 Metric: 40
LS age: 2346
Options: 2
LS Type: summary-LSA
Link State ID: 10.128.16.8 (summary Network Number)
Advertising Router: 10.128.16.3 << r03 is summarising into area1
LS Seq Number: 80000001
Checksum: 0x9262
Length: 28
Network Mask: /32
        TOS: 0 Metric: 40

8) View r01 ospf route to r08
r01-ospfd# sh ip ospf route
============ OSPF network routing table ============
...
N IA 10.128.16.8/32        [40] area: (0.0.0.0)
                           via 10.128.18.2, eth0
...
r01-ospfd#

9) View r01 zebra route to r08
r01-ospfd# exit
Connection closed by foreign host.
r01:~# telnet localhost zebra
...
Password: zebra

r01-zebra> sh ip route 10.128.16.8
Routing entry for 10.128.16.8/32
Known via "ospf", distance 110, metric 40, best
Last update 00:50:01 ago
* 10.128.18.2, via eth0

10) View r01 kernel route to r08
r01-zebra> exit
Connection closed by foreign host.
r01:~# netstat -r | grep r08
r08             10.128.18.2     255.255.255.255 UGH       0 0          0 eth0
r01:~#

11) Check OSPF reconverges after link failure
- shutdown r01 eth0
[Use zebra to shutdown the 'zebra' interface, do not use the 'ifconfig' command
to shutdown the 'kernel' interface. Other processes are using the 'kernel'
interface, so the 'ifconfig' command will fail.]

r01:~# telnet localhost zebra
...
Password: zebra
r01-zebra> en
Password: zebra
r01-zebra# conf t
r01-zebra(config)# int eth0
r01-zebra(config-if)# shutdown
r01-zebra(config-if)# end
r01-zebra#

- check int eth0 is down
r01-zebra# sh int eth0
Interface eth0
index 6 metric 1 mtu 1500 <BROADCAST,ALLMULTI,MULTICAST> << 'UP' is missing
HWaddr: fe:fd:0a:80:12:01
inet 10.128.18.1/29 broadcast 10.255.255.255
    input packets 399, bytes 27568, dropped 0, multicast packets 0
    input errors 0, length 0, overrun 0, CRC 0, frame 0, fifo 0, missed 0
    output packets 407, bytes 33854, dropped 0
    output errors 0, aborted 0, carrier 0, fifo 0, heartbeat 0, window 0
    collisions 0

- check alternate route has been found
r01-zebra# sh ip route 10.128.16.8
Routing entry for 10.128.16.8/32
Known via "ospf", distance 110, metric 50, best
Last update 00:02:41 ago
* 10.128.18.10, via eth1    << route is now via eth1 (r03)

12) Have a play ! If you completely break the lab, you can easily restore the
original setting using the 'niab restore' command on the host system.

13) Stop the lab
[ncarter:~/niab-labs/ospf]>niab stop
[ncarter:~/niab-labs/ospf]>

14) Move on to the next tutorial lab (bgp)

Appendix 1: IP Subnetting (ospf tutorial lab)

10.128.16.0/20 - Lab summary
10.128.16.0/24 - 256 x /32 dummy0
10.128.17.0/24 - Unassigned
10.128.18.0/24 - 32 x /29 Area 0 LAN links
10.128.19.0/24 - 64 x /30 Area 0 WAN links
10.128.20.0/24 - 32 x /29 Area 1 LAN links
10.128.21.0/24 - 64 x /30 Area 1 WAN links
10.128.22.0/24 - 32 x /29 Area 2 LAN links
10.128.23.0/24 - 64 x /30 Area 2 WAN links
10.128.24.0/24 - 10.128.31.0 - unassigned