Wireshark Monitor Results

[Test 1]

h4

| | |

h1 h2 h3

h1,h2,h3 are hosts. h4 will be configured as a switch. We will monitor the ping packets transmitted between h1 and h3 at host h2. Due to the mac address learning feature, we can see the arp request packet sent by h1 using broadcast at host h2. Then we can see nothing at h2. Because the switch will direct forward the packets to/from h1 and h3 directly.

mininet-script

#!/usr/bin/env python

from mininet.cli import CLI

from mininet.link import Link,TCLink,Intf

from mininet.net import Mininet

from mininet.node import RemoteController

from mininet.term import makeTerm

if '__main__' == __name__:

net = Mininet(link=TCLink)

h1 = net.addHost('h1', mac='00:00:00:00:00:11')

h2 = net.addHost('h2', mac='00:00:00:00:00:22')

h3 = net.addHost('h3', mac='00:00:00:00:00:33')

h4 = net.addHost('h4', mac='00:00:00:00:00:44')

linkopts={'bw':1}

net.addLink(h1, h4, cls=TCLink, **linkopts)

net.addLink(h2, h4, cls=TCLink, **linkopts)

net.addLink(h3, h4, cls=TCLink, **linkopts)

net.build()

h4.cmd("sudo ifconfig h4-eth0 0")

h4.cmd("sudo ifconfig h4-eth1 0")

h4.cmd("sudo ifconfig h4-eth2 0")

h4.cmd("sudo brctl addbr mybr")

h4.cmd("sudo brctl addif mybr h4-eth0")

h4.cmd("sudo brctl addif mybr h4-eth1")

h4.cmd("sudo brctl addif mybr h4-eth2")

h4.cmd("sudo ifconfig mybr up")

CLI(net)

net.stop()

execution

[Test 2]

h6

|

h5

|

h1,h2,h3,h4

h1, h2,h3,h4 are hosts, h5 is a switch, and h6 is a router.

h1 and h2 are in the same VLAN while h3 and h4 are in the same vlan.

mininet-script

#!/usr/bin/env python

from mininet.cli import CLI

from mininet.link import Link,TCLink,Intf

from mininet.net import Mininet

from mininet.node import RemoteController

if '__main__' == __name__:

net = Mininet(link=TCLink)

h1 = net.addHost('h1')

h2 = net.addHost('h2')

h3 = net.addHost('h3')

h4 = net.addHost('h4')

#h5 is a switch

h5 = net.addHost('h5')

#h6 is a switch

h6 = net.addHost('h6')

Link(h1, h5)

Link(h2, h5)

Link(h3, h5)

Link(h4, h5)

Link(h5, h6)

net.build()

h1.cmd("ifconfig h1-eth0 0")

h2.cmd("ifconfig h2-eth0 0")

h3.cmd("ifconfig h3-eth0 0")

h4.cmd("ifconfig h4-eth0 0")

h5.cmd("ifconfig h5-eth0 0")

h5.cmd("ifconfig h5-eth1 0")

h5.cmd("ifconfig h5-eth2 0")

h5.cmd("ifconfig h5-eth3 0")

h5.cmd("ifconfig h5-eth4 0")

h6.cmd("ifconfig h6-eth0 0")

h5.cmd("vconfig add h5-eth4 10")

h5.cmd("vconfig add h5-eth4 20")

h6.cmd("vconfig add h6-eth0 10")

h6.cmd("vconfig add h6-eth0 20")

h5.cmd("ifconfig h5-eth4.10 up")

h5.cmd("ifconfig h5-eth4.20 up")

h5.cmd("brctl addbr brvlan10")

h5.cmd("brctl addbr brvlan20")

h5.cmd("brctl addif brvlan10 h5-eth0")

h5.cmd("brctl addif brvlan10 h5-eth1")

h5.cmd("brctl addif brvlan10 h5-eth4.10")

h5.cmd("brctl addif brvlan20 h5-eth2")

h5.cmd("brctl addif brvlan20 h5-eth3")

h5.cmd("brctl addif brvlan20 h5-eth4.20")

h5.cmd("ifconfig brvlan10 up")

h5.cmd("ifconfig brvlan20 up")

h6.cmd("echo 1 > /proc/sys/net/ipv4/ip_forward")

h6.cmd("ifconfig h6-eth0.10 10.0.10.254 netmask 255.255.255.0")

h6.cmd("ifconfig h6-eth0.20 10.0.20.254 netmask 255.255.255.0")

h1.cmd("ifconfig h1-eth0 10.0.10.1 netmask 255.255.255.0")

h2.cmd("ifconfig h2-eth0 10.0.10.2 netmask 255.255.255.0")

h3.cmd("ifconfig h3-eth0 10.0.20.1 netmask 255.255.255.0")

h4.cmd("ifconfig h4-eth0 10.0.20.2 netmask 255.255.255.0")

h1.cmd("ip route add default via 10.0.10.254 dev h1-eth0")

h2.cmd("ip route add default via 10.0.10.254 dev h2-eth0")

h3.cmd("ip route add default via 10.0.20.254 dev h3-eth0")

h4.cmd("ip route add default via 10.0.20.254 dev h4-eth0")

h1.cmd("tcpdump -i h1-eth0 -U -w h1.log &")

h4.cmd("tcpdump -i h4-eth0 -U -w h4.log &")

h6.cmd("tcpdump -i any -U -w h6.log &")

h1.cmd("ping -c 3 10.0.20.2")

CLI(net)

net.stop()

execution

after execution, use wireshark to see the results.

h1.log: Normal Ethernet II Mac Header (No tagging)

h4.log: Normal Ethernet II Mac Header (No tagging)

h6.log: You can see 802.1Q header (Tagging)

(when h1 sends the ICMP packets to h4, we can see the VLAN ID =10)

(when h4 sends the ICMP packets to h1 we can see the VLAN ID =20)

[Test 3]

h1---h2---h3--h4---h5

h1 and h5 are hosts while h2,h3,h4 are configured as routers. We want to use "tracepath (like tracert or traceroute)" to find the path from h1 to h5.

mininet-script

#!/usr/bin/env python

from mininet.cli import CLI

from mininet.link import Link,TCLink,Intf

from mininet.net import Mininet

from mininet.node import RemoteController

if '__main__' == __name__:

net = Mininet(link=TCLink)

#h1 is a host

h1 = net.addHost('h1')

#h2 is a router

h2 = net.addHost('h2')

#h3 is a router

h3 = net.addHost('h3')

#h4 is a router

h4 = net.addHost('h4')

#h5 is a host

h5 = net.addHost('h5')

Link(h1, h2)

Link(h2, h3)

Link(h3, h4)

Link(h4, h5)

net.build()

h2.cmd('ifconfig h2-eth0 192.168.10.1 netmask 255.255.255.0')

h2.cmd('ifconfig h2-eth1 192.168.20.1 netmask 255.255.255.0')

h2.cmd("echo 1 > /proc/sys/net/ipv4/ip_forward")

h2.cmd("ip route add 192.168.30.0/24 via 192.168.20.2 dev h2-eth1")

h2.cmd("ip route add 192.168.40.0/24 via 192.168.20.2 dev h2-eth1")

h3.cmd('ifconfig h3-eth0 192.168.20.2 netmask 255.255.255.0')

h3.cmd('ifconfig h3-eth1 192.168.30.1 netmask 255.255.255.0')

h3.cmd("echo 1 > /proc/sys/net/ipv4/ip_forward")

h3.cmd("ip route add 192.168.10.0/24 via 192.168.20.1 dev h3-eth0")

h3.cmd("ip route add 192.168.40.0/24 via 192.168.30.2 dev h3-eth1")

h4.cmd('ifconfig h4-eth0 192.168.30.2 netmask 255.255.255.0')

h4.cmd('ifconfig h4-eth1 192.168.40.1 netmask 255.255.255.0')

h4.cmd("echo 1 > /proc/sys/net/ipv4/ip_forward")

h4.cmd("ip route add 192.168.10.0/24 via 192.168.30.1 dev h4-eth0")

h4.cmd("ip route add 192.168.20.0/24 via 192.168.30.1 dev h4-eth0")

h1.cmd("ifconfig h1-eth0 0")

h5.cmd("ifconfig h5-eth0 0")

h1.cmd("ip address add 192.168.10.2/24 dev h1-eth0")

h1.cmd("ip route add default via 192.168.10.1 dev h1-eth0")

h5.cmd("ip address add 192.168.40.2/24 dev h5-eth0")

h5.cmd("ip route add default via 192.168.40.1 dev h5-eth0")

h1.cmd("tcpdump -i h1-eth0 -U -w tracepathh1.log &")

CLI(net)

net.stop()

execution

Initially, ttl is set to 1. The first router will inform the sender by ICMP packet. Then the sender will know the first router address.

Then, the ttl is set to 2. The second router will inform the sender by ICMP packet due to TTL timeout. The sender will know the second router.

Similar results.

Dr. Chih-Heng Ke

Department of Computer Science and Information Engineering, National Quemoy University, Kinmen, Taiwan

Email: smallko@gmail.com