# CustomTopo.py
'''
Coursera:
- Software Defined Networking (SDN) course
-- Module 3 Programming AssignmentProfessor: Nick Feamster
Teaching Assistant: Muhammad Shahbaz
'''from mininet.topo import Topo
from mininet.net import Mininet
from mininet.node import CPULimitedHost
from mininet.link import TCLink
from mininet.util import irange,dumpNodeConnections
from mininet.log import setLogLevelclass CustomTopo(Topo):"Simple Data Center Topology""linkopts - (1:c1, 2:aggregation, 3: edge) parameters""fanout - number of child switch per parent switch"def __init__(self, linkopts1, linkopts2, linkopts3, fanout=2, **opts):# Initialize topology and default optionsTopo.__init__(self, **opts)# Add your logic here ...self.fanout = fanoutcore = self.addSwitch('c1')for i in irange(1, fanout):aggregation = self.addSwitch('a%s' %i)self.addLink(core, aggregation, **linkopts1)for j in irange(1, fanout):edge = self.addSwitch('e%s' %(fanout*(i-1)+j))self.addLink(aggregation, edge, **linkopts2)for k in irange(1, fanout):host = self.addHost('h%s' %((fanout*(fanout*(i-1)+j-1))+k))self.addLink(edge, host, **linkopts3)topos = { 'custom': ( lambda: CustomTopo() ) }def simpleTest():"Create and test a simple network"linkopts1 = dict(bw=10, delay='3ms', use_htb=True)linkopts2 = dict(bw=8, delay='4ms', loss=1, max_queue_size=900, )linkopts3 = dict(bw=6, delay='5ms', loss=1, max_queue_size=800)topo = CustomTopo(linkopts1, linkopts2, linkopts3, fanout=2)net = Mininet(topo, host=CPULimitedHost, link=TCLink)net.start()print "Dumping host connections"dumpNodeConnections(net.hosts)print "Testing network connectivity"net.pingAll()net.stop()if __name__ == '__main__':# Tell mininet to print useful informationsetLogLevel('info')simpleTest()