h1 <-> of1
h2 <-> of2
h3 <-> of2
h4 <-> of3
of1 <-> of2
of2 <-> of3

import os
from mininet.log import info
from mininet.cli import CLI
from mininet.link import TCLink
from mininet.net import Mininet
from mininet.node import RemoteController, OVSSwitch

def setup_network():
    net = Mininet(controller=RemoteController, switch=OVSSwitch, link=TCLink)

    # Add Ryu controller
    info('[+] Adding Ryu controller\n')
    c0 = net.addController('c0', controller=RemoteController)

    # Add switches, hosts, and links as before
    info('[+] Adding OpenFlow switches\n')
    of1 = net.addSwitch('of1')
    of2 = net.addSwitch('of2')
    of3 = net.addSwitch('of3')
    of4 = net.addSwitch('of4')
    of5 = net.addSwitch('of5')

    # Adding hosts
    info('[+] Adding hosts\n')
    h1 = net.addHost('h1', ip='10.0.0.1')
    h2 = net.addHost('h2', ip='10.0.0.2')
    h3 = net.addHost('h3', ip='10.0.0.3')
    h4 = net.addHost('h4', ip='10.0.0.4')
    h5 = net.addHost('h5')
    h6 = net.addHost('h6')
    
    # Adding links based on the diagram (switches connected to each other and hosts)
    info('[+] Adding links between switches, hosts, and edge servers\n')
    # Links between Switches
    net.addLink(of1, of2) # horizontal connection
    net.addLink(of2, of3)
    net.addLink(of4, of5)   
    net.addLink(of1, of4) # Vertical connection 
    net.addLink(of2, of4)
    net.addLink(of3, of5) 
    # Link between Host & Switched
    net.addLink(of1, h1)
    net.addLink(of1, h2)
    net.addLink(of2, h3)
    net.addLink(of2, h4)
    net.addLink(of3, h5)
    net.addLink(of3, h6)
    # Start the network
    net.build()
    c0.start()  # Start the controller
    net.start()

    # Discover the topology
    topology = topology_discovery(net)
    CLI(net)
    net.stop()
    return net, topology

# --------------------------------------- TOPOLOGY DISCOVERY ------------------------------------------
def topology_discovery(net):
    info('[*] Discovering topology\n')
    
    topology = {
        'switches': {},
        'hosts': {},
        'links': []
    }
    
    for switch in net.switches:
        topology['switches'][switch.name] = switch
    
    for host in net.hosts:
        topology['hosts'][host.name] = host
    
    for link in net.links:
        topology['links'].append((link.intf1.node.name, link.intf2.node.name))
    
    print("\n===================================================================================================")
    print("[!] Discovered Topology:")
    print("Switches:", topology['switches'].keys())
    print("Hosts:", topology['hosts'].keys())
    print("Links:", topology['links'])
    print("===================================================================================================")
    
    return topology


if __name__ == '__main__':
    # os.system("mn -c")
    setup_network()