[ovs-discuss] LLDP support on openvswitch

[Dave DeSimone (ddesimon)]

Thanks Ben! I¹ll keep digging.

On 5/22/15, 3:10 PM, "Ben Pfaff" <blp at nicira.com> wrote:

>On Fri, May 22, 2015 at 03:45:54AM +0000, Dave DeSimone (ddesimon) wrote:
>> Just a fundamental question, that I¹m not understanding.
>> 
>> Here is my bridge
>> 
>>     Bridge "br0"
>>         Port "br0"
>>             Interface "br0"
>>                 type: internal
>>         Port "enp130s0f0"
>>             Interface "enp130s0f0"
>>         Port "mgmt0"
>>             Interface "mgmt0"
>>                 type: internal
>> 
>> 
>> mgmt0 is carrying the ip address.
>> 
>> I¹ve added a flow with this:
>> 
>> ovs-ofctl add-flow br0 dl_type=0x88cc,action=flood
>> 
>> 
>> 
>> When I dump the flows, I see pkts
>> 
>> ovs-ofctl dump-flows br0
>> 	NXST_FLOW reply (xid=0x4):
>> 	cookie=0x0, duration=23254.816s, table=0, n_packets=4647,
>> n_bytes=1329042, idle_age=3, dl_type=0x88cc actions=FLOOD
>> 
>> 
>> 
>> 
>> I also ran tcpdump on the mgmt0 interface and I see the lldp packets
>>there.
>> 
>> 
>> So, it looks like the pkts are coming in on the physical interface
>> (enp130s0f0) and getting sent to the internal interface mgmt0. But the
>> lldp daemon running on the linux os still is not seeing the pkts.
>> 
>> 
>> Is this valid? Why wouldn¹t the lldp process see these packets is they
>> appear on the mgmt0 interface?
>
>If the packets show up in tcpdump on mgmt0, then that means that OVS
>sent them to the device.  Anything that happens beyond that point isn't
>the responsibility of OVS; OVS has no control over it.  In fact, it
>seems likely that the LLDP process receives packets from mgmt0 in the
>same way that tcpdump does, so it is a puzzle to me why it wouldn't see
>them.
>
>I know that's not really very helpful but I don't have experience with
>lldp daemons on Linux so I don't know what else to say.
>
>If you figure out what's going on then I'd be happy to add something to
>the FAQ to explain.