[pox-dev] Forwarding L2 Learning Example Behavior

[William Emmanuel Yu]

Hi all,

I am new to openflow and pox and have gone through the openflow tutorial
that uses pox. I would like some clarification on the behavior of
"installing a flow". It is my assumption that if the flow is present in
the switch then that switch won't do a packet_in anymore to the openflow
controller. However, the log below shows that even if the flow already
is in the switch it still triggered a packet_in. Is that the intended
behavior for ovsk? 

To replicate:
sudo mn --topo single,3 --mac --switch ovsk --controller remote
./pox.py log.level --DEBUG forwarding.l2_learning
pingall

The output:
POX> INFO:openflow.of_01:[Con 1/1] Connected to 00-00-00-00-00-01
DEBUG:forwarding.l2_learning:Connection [Con 1/1]
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:03.2 ->
00:00:00:00:00:02.1
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:02.1 ->
00:00:00:00:00:03.2
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:03.2 ->
00:00:00:00:00:02.1
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:04.3 ->
00:00:00:00:00:02.1
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:02.1 ->
00:00:00:00:00:04.3
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:04.3 ->
00:00:00:00:00:02.1
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:03.2 ->
00:00:00:00:00:02.1
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:02.1 ->
00:00:00:00:00:03.2
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:04.3 ->
00:00:00:00:00:03.2
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:03.2 ->
00:00:00:00:00:04.3
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:04.3 ->
00:00:00:00:00:03.2
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:04.3 ->
00:00:00:00:00:02.1
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:02.1 ->
00:00:00:00:00:04.3
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:04.3 ->
00:00:00:00:00:03.2
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:03.2 ->
00:00:00:00:00:04.3
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:04.3 ->
00:00:00:00:00:02.1
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:02.1 ->
00:00:00:00:00:04.3
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:03.2 ->
00:00:00:00:00:02.1
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:02.1 ->
00:00:00:00:00:03.2
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:04.3 ->
00:00:00:00:00:03.2
DEBUG:forwarding.l2_learning:installing flow for 00:00:00:00:00:03.2 ->
00:00:00:00:00:04.3

Finally, what is the best way to implement a traffic monitoring solution
using openflow if all packets do not generate a packet_in as intended?

Thanks.

-- 
-------------------------------------------------------
William Emmanuel S. Yu, Ph.D. (杨怀义)
Department of Information Systems and Computer Science
Ateneo de Manila University
email  :  wyu at ateneo dot edu
blog   :  http://hip2b2.yutivo.org/
web    :  http://CNG.ateneo.edu/cng/wyu/
phone  :  +63(2)4266001 loc. 4186
GPG    :  http://CNG.ateneo.net/cng/wyu/wyy.pgp

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