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How to get the path setup by ODL controller?

asked 2014-09-03 17:14:23 -0700

adisarun gravatar image

updated 2014-09-03 18:06:43 -0700

Hi,

I have a custom topology created using mininet with multiple paths between a pair of hosts (topology script below). Ping between the hosts works. But I would like to know which path has been selected by the opendaylight controller.

traceroute from host 1 just prints the following:

root@ubuntu:~/Desktop# traceroute
10.0.0.2 traceroute to 10.0.0.2 (10.0.0.2), 30 hops max, 60 byte packets  1  10.0.0.2 (10.0.0.2)  0.304 ms  0.135 ms  0.187 ms

Multipath Mininet Topology Script:

def mpTopo():
    "Create an empty network and add nodes to it."

    info( '*** Adding controller\n' )
    ctrlr = lambda n: RemoteController(n, ip='127.0.0.1')
    net = Mininet(controller=ctrlr)
    c0 = net.addController('c0')    

    info( '*** Adding hosts\n' )
    leftHost = net.addHost('h1')
    rightHost = net.addHost('h2')

    info( '*** Adding switch\n' )
    leftSwitch = net.addSwitch('s3')
    rightSwitch = net.addSwitch('s4')
    thirdSwitch = net.addSwitch('s5')

    info( '*** Creating links\n' )
    net.addLink(leftHost, leftSwitch)
    net.addLink(leftSwitch, rightSwitch)
    net.addLink(rightSwitch, rightHost)
    net.addLink(rightSwitch, thirdSwitch)
    net.addLink(leftSwitch, thirdSwitch)

    info( '*** Starting network\n')
    net.start()

    info( '*** Running CLI\n' )
    CLI(net)

    info( '*** Stopping network' )
    net.stop()

if __name__ == '__main__':
    setLogLevel( 'info' )
    mpTopo()

EDIT: I ran wireshark tool to capture "lo" interface traffic and applied "of" filter. It also just shows the mac addresses of two hosts as source and destination when I ran ping command. I could not figure out which path has been chosen. Attached screenshot. I'm not sure where I'm wrong. Please advise.

traceroute.png

Please help. Thanks.

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answered 2014-09-07 20:12:42 -0700

Moderators

Firstly thing trace route won't work as no device in the path is decrementing the TTL field.

One way to get this sort of information is to check the flow table of the device, and see which port the packet is output to. Then checking the topography to see what is the next switch you have to check.

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Hi Chris, by "check the flow table of the device", do you mean a switch in the topology? If so, what is the command I need to use to get that information?

adisarun ( 2014-09-12 11:45:20 -0700 )edit

Not sure which OpenFlow you're using the one inbuild to the controller or the plugin (-of13) http://<controller ip="">:8080/restconf/config/opendaylight-inventory:nodes/node/openflow:<dpid>

Chris O'Shea ( 2014-09-12 16:08:30 -0700 )edit

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Asked: 2014-09-03 17:14:23 -0700

Seen: 384 times

Last updated: Sep 07 '14