Stoachastic Switching using Open vSwitch in Mininet

[Description]

OpenFlow 1.3 implements group table feature and select group type. The default implementation of select group type in OVS 2.1 randomly selects a bucket from among the live buckets based on destination MAC. Therefore, I found https://github.com/saeenali/openvswitch/wiki/Stochastic-Switching-using-Open-vSwitch-in-Mininet. The author uses the select group type to probabilistically select a group action bucket. The author generates a random number to represent the probability for choosing a bucket. This probability and bucket weights are used to select a bucket. In that webpage, the author described clearly how to modify the ofproto-dpif-xlate.c. However, it may be difficult for beginners to do the job. So I do all the things and prepare a VM (sdnhub_stoachastic_switch.zip). Everything is included. Just download this file and decompress it. Then use virtualbox to import the ova file.

p.s. The original weight is between 1 and 10. I have modified the code to make weight between 1 and 100.

[Topology: refer to the original webpage]

[Script]

(topology.py)

#!/usr/bin/python

"""Topology with 10 switches and 10 hosts

"""

from mininet.cli import CLI

from mininet.topo import Topo

from mininet.net import Mininet

from mininet.link import TCLink

from mininet.log import setLogLevel

class CSLRTopo( Topo ):

def __init__( self ):

"Create Topology"

# Initialize topology

Topo.__init__( self )

# Add hosts

h0 = self.addHost( 'h0' )

h1 = self.addHost( 'h1' )

h2 = self.addHost( 'h2' )

h3 = self.addHost( 'h3' )

h4 = self.addHost( 'h4' )

h5 = self.addHost( 'h5' )

h6 = self.addHost( 'h6' )

h7 = self.addHost( 'h7' )

h8 = self.addHost( 'h8' )

h9 = self.addHost( 'h9' )

# Add switches

s0 = self.addSwitch( 's0', listenPort=6634 )

s1 = self.addSwitch( 's1', listenPort=6635 )

s2 = self.addSwitch( 's2', listenPort=6636 )

s3 = self.addSwitch( 's3', listenPort=6637 )

s4 = self.addSwitch( 's4', listenPort=6638 )

s5 = self.addSwitch( 's5', listenPort=6639 )

s6 = self.addSwitch( 's6', listenPort=6640 )

s7 = self.addSwitch( 's7', listenPort=6641 )

s8 = self.addSwitch( 's8', listenPort=6642 )

s9 = self.addSwitch( 's9', listenPort=6643 )

# Add links between hosts and switches

self.addLink( h0, s0 ) # h0-eth0 <-> s0-eth1

self.addLink( h1, s1 ) # h1-eth0 <-> s1-eth1

self.addLink( h2, s2 ) # h2-eth0 <-> s2-eth1

self.addLink( h3, s3 ) # h3-eth0 <-> s3-eth1

self.addLink( h4, s4 ) # h4-eth0 <-> s4-eth1

self.addLink( h5, s5 ) # h5-eth0 <-> s5-eth1

self.addLink( h6, s6 ) # h6-eth0 <-> s6-eth1

self.addLink( h7, s7 ) # h7-eth0 <-> s7-eth1

self.addLink( h8, s8 ) # h8-eth0 <-> s8-eth1

self.addLink( h9, s9 ) # h9-eth0 <-> s9-eth1

# Add links between switches, with bandwidth 100Mbps

self.addLink( s0, s1, bw=100 ) # s0-eth2 <-> s1-eth2, Bandwidth = 100Mbps

self.addLink( s0, s2, bw=100 ) # s0-eth3 <-> s2-eth2, Bandwidth = 100Mbps

self.addLink( s1, s2, bw=100 ) # s1-eth3 <-> s2-eth3, Bandwidth = 100Mbps

self.addLink( s2, s3, bw=100 ) # s2-eth4 <-> s3-eth2, Bandwidth = 100Mbps

self.addLink( s3, s4, bw=100 ) # s3-eth3 <-> s4-eth2, Bandwidth = 100Mbps

self.addLink( s3, s6, bw=100 ) # s3-eth4 <-> s6-eth2, Bandwidth = 100Mbps

self.addLink( s4, s5, bw=100 ) # s4-eth3 <-> s5-eth2, Bandwidth = 100Mbps

self.addLink( s5, s7, bw=100 ) # s5-eth3 <-> s7-eth2, Bandwidth = 100Mbps

self.addLink( s6, s7, bw=100 ) # s6-eth3 <-> s7-eth3, Bandwidth = 100Mbps

self.addLink( s7, s8, bw=100 ) # s7-eth4 <-> s8-eth2, Bandwidth = 100Mbps

self.addLink( s7, s9, bw=100 ) # s7-eth5 <-> s9-eth2, Bandwidth = 100Mbps

self.addLink( s8, s9, bw=100 ) # s8-eth3 <-> s9-eth3, Bandwidth = 100Mbps

def run():

"Create and configure network"

topo = CSLRTopo()

net = Mininet( topo=topo, link=TCLink, controller=None )

# Set interface IP and MAC addresses for hosts

h0 = net.get( 'h0' )

h0.intf( 'h0-eth0' ).setIP( '10.0.0.2', 24 )

h0.intf( 'h0-eth0' ).setMAC( '0A:00:00:02:00:00' )

h1 = net.get( 'h1' )

h1.intf( 'h1-eth0' ).setIP( '10.0.1.2', 24 )

h1.intf( 'h1-eth0' ).setMAC( '0A:00:01:02:00:00' )

h2 = net.get( 'h2' )

h2.intf( 'h2-eth0' ).setIP( '10.0.2.2', 24 )

h2.intf( 'h2-eth0' ).setMAC( '0A:00:02:02:00:00' )

h3 = net.get( 'h3' )

h3.intf( 'h3-eth0' ).setIP( '10.0.3.2', 24 )

h3.intf( 'h3-eth0' ).setMAC( '0A:00:03:02:00:00' )

h4 = net.get( 'h4' )

h4.intf( 'h4-eth0' ).setIP( '10.0.4.2', 24 )

h4.intf( 'h4-eth0' ).setMAC( '0A:00:04:02:00:00' )

h5 = net.get( 'h5' )

h5.intf( 'h5-eth0' ).setIP( '10.0.5.2', 24 )

h5.intf( 'h5-eth0' ).setMAC( '0A:00:05:02:00:00' )

h6 = net.get( 'h6' )

h6.intf( 'h6-eth0' ).setIP( '10.0.6.2', 24 )

h6.intf( 'h6-eth0' ).setMAC( '0A:00:06:02:00:00' )

h7 = net.get( 'h7' )

h7.intf( 'h7-eth0' ).setIP( '10.0.7.2', 24 )

h7.intf( 'h7-eth0' ).setMAC( '0A:00:07:02:00:00' )

h8 = net.get( 'h8' )

h8.intf( 'h8-eth0' ).setIP( '10.0.8.2', 24 )

h8.intf( 'h8-eth0' ).setMAC( '0A:00:08:02:00:00' )

h9 = net.get( 'h9' )

h9.intf( 'h9-eth0' ).setIP( '10.0.9.2', 24 )

h9.intf( 'h9-eth0' ).setMAC( '0A:00:09:02:00:00' )

# Set interface MAC address for switches (NOTE: IP

# addresses are not assigned to switch interfaces)

s0 = net.get( 's0' )

s0.intf( 's0-eth1' ).setMAC( '0A:00:00:01:00:01' )

s0.intf( 's0-eth2' ).setMAC( '0A:00:0A:01:00:02' )

s0.intf( 's0-eth3' ).setMAC( '0A:00:0B:01:00:03' )

s1 = net.get( 's1' )

s1.intf( 's1-eth1' ).setMAC( '0A:00:01:01:00:01' )

s1.intf( 's1-eth2' ).setMAC( '0A:00:0A:FE:00:02' )

s1.intf( 's1-eth3' ).setMAC( '0A:00:0C:01:00:03' )

s2 = net.get( 's2' )

s2.intf( 's2-eth1' ).setMAC( '0A:00:02:01:00:01' )

s2.intf( 's2-eth2' ).setMAC( '0A:00:0B:FE:00:02' )

s2.intf( 's2-eth3' ).setMAC( '0A:00:0D:01:00:03' )

s2.intf( 's2-eth4' ).setMAC( '0A:00:0C:FE:00:04' )

s3 = net.get( 's3' )

s3.intf( 's3-eth1' ).setMAC( '0A:00:03:01:00:01' )

s3.intf( 's3-eth2' ).setMAC( '0A:00:0D:FE:00:02' )

s3.intf( 's3-eth3' ).setMAC( '0A:00:0E:01:00:03' )

s3.intf( 's3-eth4' ).setMAC( '0A:00:0F:01:00:04' )

s4 = net.get( 's4' )

s4.intf( 's4-eth1' ).setMAC( '0A:00:04:01:00:01' )

s4.intf( 's4-eth2' ).setMAC( '0A:00:0E:FE:00:02' )

s4.intf( 's4-eth3' ).setMAC( '0A:00:10:01:00:03' )

s5 = net.get( 's5' )

s5.intf( 's5-eth1' ).setMAC( '0A:00:05:01:00:01' )

s5.intf( 's5-eth2' ).setMAC( '0A:00:10:FE:00:02' )

s5.intf( 's5-eth3' ).setMAC( '0A:00:11:01:00:03' )

s6 = net.get( 's6' )

s6.intf( 's6-eth1' ).setMAC( '0A:00:06:01:00:01' )

s6.intf( 's6-eth2' ).setMAC( '0A:00:0F:FE:00:02' )

s6.intf( 's6-eth3' ).setMAC( '0A:00:12:01:00:03' )

s7 = net.get( 's7' )

s7.intf( 's7-eth1' ).setMAC( '0A:00:07:01:00:01' )

s7.intf( 's7-eth2' ).setMAC( '0A:00:11:FE:00:02' )

s7.intf( 's7-eth3' ).setMAC( '0A:00:12:FE:00:03' )

s7.intf( 's7-eth4' ).setMAC( '0A:00:13:01:00:04' )

s7.intf( 's7-eth5' ).setMAC( '0A:00:14:01:00:05' )

s8 = net.get( 's8' )

s8.intf( 's8-eth1' ).setMAC( '0A:00:08:01:00:01' )

s8.intf( 's8-eth2' ).setMAC( '0A:00:13:FE:00:02' )

s8.intf( 's8-eth3' ).setMAC( '0A:00:15:01:00:03' )

s9 = net.get( 's9' )

s9.intf( 's9-eth1' ).setMAC( '0A:00:09:01:00:01' )

s9.intf( 's9-eth2' ).setMAC( '0A:00:14:FE:00:02' )

s9.intf( 's9-eth3' ).setMAC( '0A:00:15:FE:00:03' )

net.start()

# Add routing table entries for hosts (NOTE: The gateway

# IPs 10.0.X.1 are not assigned to switch interfaces)

h0.cmd( 'route add default gw 10.0.0.1 dev h0-eth0' )

h1.cmd( 'route add default gw 10.0.1.1 dev h1-eth0' )

h2.cmd( 'route add default gw 10.0.2.1 dev h2-eth0' )

h3.cmd( 'route add default gw 10.0.3.1 dev h3-eth0' )

h4.cmd( 'route add default gw 10.0.4.1 dev h4-eth0' )

h5.cmd( 'route add default gw 10.0.5.1 dev h5-eth0' )

h6.cmd( 'route add default gw 10.0.6.1 dev h6-eth0' )

h7.cmd( 'route add default gw 10.0.7.1 dev h7-eth0' )

h8.cmd( 'route add default gw 10.0.8.1 dev h8-eth0' )

h9.cmd( 'route add default gw 10.0.9.1 dev h9-eth0' )

# Add arp cache entries for hosts

h0.cmd( 'arp -s 10.0.0.1 0A:00:00:01:00:01 -i h0-eth0' )

h1.cmd( 'arp -s 10.0.1.1 0A:00:01:01:00:01 -i h1-eth0' )

h2.cmd( 'arp -s 10.0.2.1 0A:00:02:01:00:01 -i h2-eth0' )

h3.cmd( 'arp -s 10.0.3.1 0A:00:03:01:00:01 -i h3-eth0' )

h4.cmd( 'arp -s 10.0.4.1 0A:00:04:01:00:01 -i h4-eth0' )

h5.cmd( 'arp -s 10.0.5.1 0A:00:05:01:00:01 -i h5-eth0' )

h6.cmd( 'arp -s 10.0.6.1 0A:00:06:01:00:01 -i h6-eth0' )

h7.cmd( 'arp -s 10.0.7.1 0A:00:07:01:00:01 -i h7-eth0' )

h8.cmd( 'arp -s 10.0.8.1 0A:00:08:01:00:01 -i h8-eth0' )

h9.cmd( 'arp -s 10.0.9.1 0A:00:09:01:00:01 -i h9-eth0' )

# Open Mininet Command Line Interface

CLI(net)

# Teardown and cleanup

net.stop()

if __name__ == '__main__':

setLogLevel('info')

run()

(script_topology)

# ADD-GROUP at s7 for [0, 9]

ovs-ofctl -O OpenFlow13 add-group tcp:127.0.0.1:6641 group_id=0,type=select,bucket=weight:65,mod_dl_src:0A:00:14:01:00:05,mod_dl_dst:0A:00:14:FE:00:02,output=5,bucket=weight:35,mod_dl_src:0A:00:13:01:00:04,mod_dl_dst:0A:00:13:FE:00:02,output=4

# ADD-FLOW(s) for [0, 9] at [0, 2, 3, 6, 7, 8, 9]

ovs-ofctl -O OpenFlow13 add-flow tcp:127.0.0.1:6634 in_port=1,ip,nw_src=10.0.0.2,nw_dst=10.0.9.2,actions=mod_dl_src:0A:00:0B:01:00:03,mod_dl_dst:0A:00:0B:FE:00:02,output=3

ovs-ofctl -O OpenFlow13 add-flow tcp:127.0.0.1:6636 in_port=2,ip,nw_src=10.0.0.2,nw_dst=10.0.9.2,actions=mod_dl_src:0A:00:0D:01:00:04,mod_dl_dst:0A:00:0D:FE:00:02,output=4

ovs-ofctl -O OpenFlow13 add-flow tcp:127.0.0.1:6637 in_port=2,ip,nw_src=10.0.0.2,nw_dst=10.0.9.2,actions=mod_dl_src:0A:00:0F:01:00:04,mod_dl_dst:0A:00:0F:FE:00:02,output=4

ovs-ofctl -O OpenFlow13 add-flow tcp:127.0.0.1:6640 in_port=2,ip,nw_src=10.0.0.2,nw_dst=10.0.9.2,actions=mod_dl_src:0A:00:12:01:00:03,mod_dl_dst:0A:00:12:FE:00:03,output=3

ovs-ofctl -O OpenFlow13 add-flow tcp:127.0.0.1:6641 in_port=3,ip,nw_src=10.0.0.2,nw_dst=10.0.9.2,actions=group=0

ovs-ofctl -O OpenFlow13 add-flow tcp:127.0.0.1:6643 in_port=2,ip,nw_src=10.0.0.2,nw_dst=10.0.9.2,actions=mod_dl_src:0A:00:09:01:00:01,mod_dl_dst:0A:00:09:02:00:00,output=1

ovs-ofctl -O OpenFlow13 add-flow tcp:127.0.0.1:6642 in_port=2,ip,nw_src=10.0.0.2,nw_dst=10.0.9.2,actions=mod_dl_src:0A:00:15:01:00:03,mod_dl_dst:0A:00:15:FE:00:03,output=3

ovs-ofctl -O OpenFlow13 add-flow tcp:127.0.0.1:6643 in_port=3,ip,nw_src=10.0.0.2,nw_dst=10.0.9.2,actions=mod_dl_src:0A:00:09:01:00:01,mod_dl_dst:0A:00:09:02:00:00,output=1

[Execution]

Open one terminal to run topology.py

Open another terminal to run the script_topology. This will create the rules for those switches.

Check the rule, group, and port information for switch 7 (s7)

Run iperf between h0 and h9

check the port information for s7. We can find that the port 4 has sent out 14774 packets and port 5 has sent out 27591 packets. Port 5: 27591/(14774+27591) * 100% = 65.1% Port 4:14774/(14774+27591)*100%=34.87%

The results are very close to our setting (Port 5: weight=65, Port 4: weight=35)

Dr. Chih-Heng Ke

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

Email: smallko@gmail.com