[ovs-discuss] Traffic loop problem, when a controller is setted

[MIGNINI FABIO]

Thank you very much for your answer.
By setting the controller connection out of band I solved 
the problem.

Best regards,
Fabio Mignini

On Wed, 18 Mar 2015 08:41:19 -0700
  Ben Pfaff <blp at nicira.com> wrote:
> On Tue, Mar 17, 2015 at 06:57:58PM +0100, MIGNINI FABIO 
>wrote:
>> I have noticed an unexpected generation of traffic loop 
>>using a very simple
>> configuration of KVM and OVS.
>> In particular the configuration that trigger the problem 
>>is the one listed
>> below:
>> 
>>    +-----------------+
>>    | Virtual machine |
>>    +----+-------+----+
>>         |       |
>>  +------+-------+------+
>>  |                     |
>>  |     OVS Bridge      |
>>  +---------------------+
>> 
>> The OVS Bridge has two ports that are connected to the 
>>virtual machine.
>> Within the virtual machine there is a linux bridge that 
>>bridges both the
>> vm's interfaces.
>> I found the problem with two different configuration of 
>>the bridge:
>> 	- setting an existing OF controller (OpenDaylight)
>>         - setting a fake address for the OF controller 
>>(a not reachable IP
>> address)
>> 
>> This is the output of the 'ovs-vsctl show' command (I 
>>provide here only the
>> second configuration, as you can see the controller is 
>>not connected):
>> 
>> root at controller:~# ovs-vsctl show
>> 82f530a0-269e-4eb4-b71a-dedc9f26ccd9
>>     Bridge br-int
>>         Controller "tcp:192.168.5.3:6633"
>>         Port br-int
>>             Interface br-int
>>                 type: internal
>>         Port "vnet1"
>>             Interface "vnet1"
>>         Port "vnet0"
>>             Interface "vnet0"
>>     ovs_version: "2.3.1"
>> 
>> The only flow in the OVS bridge "br-int" is a DROP flow, 
>>without any match
>> (inserted manually before the starting of the virtual 
>>machine).
>> This is the output of the 'ovs-ofctl dump-flows br-int' 
>>command:
>> 
>> root at controller:~# ovs-ofctl dump-flows br-int
>> NXST_FLOW reply (xid=0x4):
>>  cookie=0x0, duration=232.952s, table=0, n_packets=0, 
>>n_bytes=0,
>> idle_age=232, priority=1 actions=drop
>> 
>> With this configuration I was expecting that all the 
>>traffic will be dropped
>> by the OVS Bridge (as happens when no controller is 
>>setted).
>> Instead a traffic loop is generated between the two 
>>ports in the bridge.
>> It seems that the DROP flow rule is not working as 
>>expected.
> 
> One possibility is that you've got hidden flows due to 
>the in-band
> controller configuration.  Try "ovs-appctl 
>bridge/dump-flows br-int" to
> check for thtat.
> _______________________________________________
> discuss mailing list
> discuss at openvswitch.org
> http://openvswitch.org/mailman/listinfo/discuss