Thank you very much for your reply! See below.
At 2014-08-20 02:48:33, "Murphy McCauley" <murphy.mccau...@gmail.com> wrote:
On Aug 19, 2014, at 8:22 PM, 张伟 <zhang...@126.com> wrote:
Hi all,
I want to know for the application eg l2_learning. If we run this component,
l2_learning is single thread or multi-thread?
Single threaded.
My simple test:
def _handle_PacketIn (event):
packet = event.parsed
msg = of.ofp_flow_mod()
msg.match = of.ofp_match.from_packet(packet, event.port);
msg.buffer_id = event.ofp.buffer_id
log.info("buffer_id %i", msg.buffer_id);
msg.idle_timeout = 10
msg.hard_timeout = 30
msg.actions.append(of.ofp_action_output(port = 0))
msg.data = event.ofp
event.connection.send(msg)
When I print out the buffer_id message, sometimes it is not sequence. I got the
result like that:
INFO:packet:(udp parse) warning UDP packet data shorter than UDP len: 96 < 962
INFO:misc.test_flow_miss:buffer_id 0
INFO:openflow.of_01:[00-00-00-00-00-01 2] connected
INFO:packet:(udp parse) warning UDP packet data shorter than UDP len: 96 < 962
INFO:misc.test_flow_miss:buffer_id 2
This makes me very confused. At first, I thought just one single thread for the
app. app processed the requests according to FIFO mode. Can anybody give some
help and explain some reason for my result?
The buffers come from the switches. How the switches decide on buffer IDs is
not specified. Are you sure your switch is sending buffer IDs that increment
by one? Have you snooped the control connection to confirm this?
Another possibility is that a higher priority packet-in handler is getting the
event first and eating it. If all you're running is l2_learning (and not, say,
discovery) this shouldn't be the case, though.
Yes, I am sure that the switch sends the buffer IDs that increment by one.
Actually the buffer ID starts from 0. On my above component, from the log.info
I can see that the buffer id starts from 0. However, on the switch side, when
receiving the flow_mod message, the first buffer_id is always UINT32_MAX. On
the controller side, I only run my own component. So this repsents other
component sends the flow_mod message with buffer_id is UINT32_MAX. Do you think
where can send this message?
Another question:
In pox wiki, when we want to install a flow entry: if the tcp port is 8080, why
in python code, we do not need to do htons translation. However, the switch
side receives the port is network endian.
Because it would be awful if you had to do it yourself and POX takes care of it
for you.
Can you help to point out where in pox do the translation?
-- Murphy
