============================================================
topology
============================================================


      +-------+         +--------+
      |       |         |        |
      |  PC1  +---------+ router1|
      |       |eth1 eth2|  eth1  | 
      +-------+         +--------+
                            |                     
                            |
                            |
                            |
      +-------+         +--------+         
      |       |         |  eth1  |         
      |  PC2  +---------+ router2|         
      |       |eth1 eth2|        | 
      +-------+         +--------+         

============================================================
How to run this lab? Clone the repo and deploy the topology
============================================================
$ git clone git@github.com:protonpchan/frr-single-ospf.git
$ cd frr-single-ospf/
$ ./run

INFO[0000] Parsing & checking topology file: lab.yml    
INFO[0000] Destroying lab: lab                          
INFO[0000] Removed container: clab-lab-router2          
INFO[0000] Removed container: clab-lab-PC1              
INFO[0000] Removed container: clab-lab-PC2              
INFO[0000] Removed container: clab-lab-router1          
INFO[0000] Removing containerlab host entries from /etc/hosts file 
pchan@LAPTOP-UP9VD31I:/tmp/frr-single-ospf$ ./run.sh 
INFO[0000] Containerlab v0.46.1 started                 
INFO[0000] Parsing & checking topology file: lab.yml    
INFO[0000] Creating docker network: Name="clab", IPv4Subnet="172.20.20.0/24", IPv6Subnet="2001:172:20:20::/64", MTU="1500" 
INFO[0000] Creating lab directory: /tmp/frr-single-ospf/clab-lab 
INFO[0000] Creating container: "router2"                
INFO[0000] Creating container: "PC2"                    
INFO[0000] Creating container: "router1"                
INFO[0000] Creating container: "PC1"                    
INFO[0000] Creating link: router1:eth1 <--> router2:eth1 
INFO[0000] Creating link: PC1:eth1 <--> router1:eth2    
INFO[0000] Creating link: PC2:eth1 <--> router2:eth2    
INFO[0001] Adding containerlab host entries to /etc/hosts file 
+---+------------------+--------------+---------------------------------+-------+---------+----------------+----------------------+
| # |       Name       | Container ID |              Image              | Kind  |  State  |  IPv4 Address  |     IPv6 Address     |
+---+------------------+--------------+---------------------------------+-------+---------+----------------+----------------------+
| 1 | clab-lab-PC1     | 7dacd946c6f8 | praqma/network-multitool:latest | linux | running | 172.20.20.4/24 | 2001:172:20:20::4/64 |
| 2 | clab-lab-PC2     | 6cd2b5f74aba | praqma/network-multitool:latest | linux | running | 172.20.20.5/24 | 2001:172:20:20::5/64 |
| 3 | clab-lab-router1 | a8a52d036c11 | frrouting/frr:v7.5.1            | linux | running | 172.20.20.3/24 | 2001:172:20:20::3/64 |
| 4 | clab-lab-router2 | 3ffa1bc9d2a3 | frrouting/frr:v7.5.1            | linux | running | 172.20.20.2/24 | 2001:172:20:20::2/64 |
+---+------------------+--------------+---------------------------------+-------+---------+----------------+----------------------+

============================================================
Test the connectivity
============================================================
docker exec clab-lab-router1 ping 192.168.12.2
docker exec clab-lab-router1 ping 10.10.10.2
docker exec clab-lab-router1 ping 192.168.2.1

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You can login FRR virtual device, and do "show" commands
============================================================
$ docker exec -it clab-lab-router1 bash
bash-5.1# vtysh
router1# show ip ospf neighbor
Neighbor ID     Pri State           Dead Time Address         Interface                        RXmtL RqstL DBsmL
10.10.10.2        1 Full/DR           36.685s 192.168.12.2    eth1:192.168.12.1                    0     0     0