Openvswitch Port Mirroring

[Topology]

There are three hosts, i.e. h1, h2, h3, that are connecting to an openvswitch(s1). We want the port 3 (connecting to h3) to be the mirroring port that can monitor the traffic between h1 and h2.

[Mininet Script]

#!/usr/bin/env python

from mininet.cli import CLI

from mininet.net import Mininet

from mininet.link import Link,TCLink,Intf

from mininet.node import Controller

if '__main__' == __name__:

net = Mininet(link=TCLink)

h1 = net.addHost('h1')

h2 = net.addHost('h2')

h3 = net.addHost('h3')

s1 = net.addSwitch('s1')

c0 = net.addController('c0', controller=Controller)

net.addLink(h1, s1)

net.addLink(h2, s1)

net.addLink(h3, s1)

net.build()

c0.start()

#open a terminal for s1 and type the following commands

#ovs-vsctl del-port s1-eth3

#ovs-vsctl add-port s1 s1-eth3 -- --id=@p get port s1-eth3 -- --id=@m create mirror name=m0 select-all=true output-port=@p -- set bridge s1 mirrors=@m

s1.start([c0])

CLI(net)

net.stop()

[execution]

With this feature, we can install machine learning, IDS/IPS or other mechanism for traffic analysis in h3.

[Reference]

http://docs.openvswitch.org/en/latest/faq/configuration/

Dr. Chih-Heng Ke (smallko@gmail.com)

Department of Computer Science and Information Engineering,

National Quemoy University, Kinmen, Taiwan.