def testLinkLoss(self):
"Verify that we see packet drops with a high configured loss rate."
LOSS_PERCENT = 99
REPS = 1
lopts = {'loss': LOSS_PERCENT, 'use_htb': True}
mn = Mininet(topo=SingleSwitchOptionsTopo(n=N, lopts=lopts),
host=CPULimitedHost,
link=TCLink,
switch=self.switchClass,
waitConnected=True)
# Drops are probabilistic, but the chance of no dropped packets is
# 1 in 100 million with 4 hops for a link w/99% loss.
dropped_total = 0
mn.start()
for _ in range(REPS):
dropped_total += mn.ping(timeout='1')
mn.stop()
loptsStr = ', '.join('%s: %s' % (opt, value)
for opt, value in lopts.items())
msg = ('\nTesting packet loss with %d%% loss rate\n'
'number of dropped pings during mininet.ping(): %s\n'
'expected number of dropped packets: 1\n'
'Topo = SingleSwitchTopo, %s hosts\n'
'Link = TCLink\n'
'lopts = %s\n'
'host = default\n'
'switch = %s\n' %
(LOSS_PERCENT, dropped_total, N, loptsStr, self.switchClass))
self.assertGreater(dropped_total, 0, msg)
def linearBandwidthTest(lengths):
"Check bandwidth at various lengths along a switch chain."
results = {}
switchCount = max(lengths)
hostCount = switchCount + 1
switches = {
'reference user': UserSwitch,
'Open vSwitch kernel': OVSKernelSwitch
}
# UserSwitch is horribly slow with recent kernels.
# We can reinstate it once its performance is fixed
del switches['reference user']
topo = LinearTestTopo(hostCount)
# Select TCP Reno
output = quietRun('sysctl -w net.ipv4.tcp_congestion_control=reno')
assert 'reno' in output
for datapath in switches.keys():
print "*** testing", datapath, "datapath"
Switch = switches[datapath]
results[datapath] = []
link = partial(TCLink, delay='1ms')
net = Mininet(topo=topo,
switch=Switch,
controller=Controller,
waitConnected=True,
link=link)
net.start()
print "*** testing basic connectivity"
for n in lengths:
net.ping([net.hosts[0], net.hosts[n]])
print "*** testing bandwidth"
for n in lengths:
src, dst = net.hosts[0], net.hosts[n]
# Try to prime the pump to reduce PACKET_INs during test
# since the reference controller is reactive
src.cmd('telnet', dst.IP(), '5001')
print "testing", src.name, "<->", dst.name,
bandwidth = net.iperf([src, dst], seconds=10)
print bandwidth
flush()
results[datapath] += [(n, bandwidth)]
net.stop()
for datapath in switches.keys():
print
print "*** Linear network results for", datapath, "datapath:"
print
result = results[datapath]
print "SwitchCount\tiperf Results"
for switchCount, bandwidth in result:
print switchCount, '\t\t',
print bandwidth[0], 'server, ', bandwidth[1], 'client'
print
print