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I have 4 Virtual Machines (Ubuntu 12.04) running on a host that is also running Ubuntu 12.04. The Virtual Machines are named:

switch-vm
vm-1
vm-2
vm-3

Below are the network settings on switch-vm:

Adapter 1:
    Intel PRO/1000 MT Desktop (Bridged adapter, eth0)
Adapter 2:
    Intel PRO/1000 MT Desktop (Internal network, 'intnet-1')
Adapter 3:
    Intel PRO/1000 MT Desktop (Internal network, 'intnet-2')
Adapter 4:
    Intel PRO/1000 MT Desktop (Internal network, 'intnet-3')

Network settings on vm-1:

Adapter 1:
    Intel PRO/1000 MT Desktop (Bridged adapter, eth0)
Adapter 2:
    Intel PRO/1000 MT Desktop (Internal network, 'intnet-1')

Network settings on vm-2:

Adapter 1:
    Intel PRO/1000 MT Desktop (Bridged adapter, eth0)
Adapter 2:
    Intel PRO/1000 MT Desktop (Internal network, 'intnet-2')

Network settings on vm-3:

Adapter 1:
    Intel PRO/1000 MT Desktop (Bridged adapter, eth0)
Adapter 2:
    Intel PRO/1000 MT Desktop (Internal network, 'intnet-3')

I have installed openvswitch on switch-vm:

sudo ovs-vsctl show 
sudo ovs-vsctl add-br lan0
sudo ovs-vsctl add-port lan0 eth1
sudo ovs-vsctl add-port lan0 eth4
sudo ovs-vsctl add-port lan0 eth5

This makes the connections as below.

eth 1 on switch-vm ----- eth1 on vm-1
eth 4 on switch-vm ----- eth1 on vm-2
eth 5 on switch-vm ----- eth1 on vm-3

Please note that the six interfaces mentioned above do not have IP addresses. The ifconfig on the interfaces will look somewhat like below. (example: eth4 on switch-vm)

eth4      Link encap:Ethernet  HWaddr 08:00:27:80:e2:be  
          inet6 addr: fe80::a00:27ff:fe80:e2be/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:44 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:8538 (8.5 KB)

I want to make sure that traffic flows across all the three connections mentioned above, both ways.

Is there a way I can use ping or some other similar tool for this purpose? If yes, how?

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2 Answers 2

While I don't have openvswitch installed, there are a few standard switch methods to see if each device is connected in the manner expected. I'm not sure of the exact command or the syntax, although I did look on their website...

If you were on a cisco switch

show cam

would show all the MAC addresses the switch sees, and the ports and VLANs to which they're attached. Before this works, you might have to send a broadcast ping (ping 255.255.255.255) to make sure all hosts have done an ARP and thus show up in the CAM table.

It would appear the equivalent command for your setup would be

ovs−ofctl dump−tables br0

Prints out the switch’s table stats. (This is more interesting after some traffic has passed through.)

(possibly vsctl)

http://openvswitch.org/cgi-bin/ovsman.cgi?page=utilities%2Fovs-ofctl.8

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As you've mentioned, you don't have IP addresses in this network. That is valid for IPv4, but IPv6 has link local addresses for each device inherited from NIC MAC addresses, note this:

    inet6 addr: fe80::a00:27ff:fe80:e2be/64 Scope:Link

Assuming that each machine is Linux os OSX, you can ping each machine over IPV6:

Example ping from vm-1 to switch-vm:

    root@switch-vm:~# ping6 -I intnet-1 fe80::a00:27ff:fe80:e2be

If you're wondering what is link-local ip-address of particular ethernet NIC, you can use online converter http://ben.akrin.com/?p=1347

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IPv4 has link local addresses too; they're just randomly assigned with ARPs to verify, fingers-crossed, not well-defined like IPv6's are. –  Jason C Aug 15 at 11:43
    
Thanks, didn't know that these strange IP addresses 169.* found on some Windows boxes are just Link Local addresses assigned using some "standarized" rule ... Good to know. –  Zbigniew Zagórski Aug 15 at 11:47
    
Welcome to SU, by the way! If you make a mistake in a comment, there is an 'edit' button just after the comment, and also if you hold your mouse over it, an 'X' appears that can be used to delete it. Comments can only be edited for 5 minutes but can be deleted at any time. :) –  Jason C Aug 15 at 11:48

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