On 3/25/2011 2:34 AM, Murphy McCauley wrote:
It's true that pyswitch does install flows with a timeout. However,
there's another reason as well: NOX deletes all flows on a switch when
the switch connects (in builtin/nox.cc).
If it didn't, it's difficult to reason about what installing a
particular flow would actually do (e.g., possibly nothing). That
said, I've wondered for a while whether this should actually be an
option, so that a clever application COULD actually inspect the flow
table on switch connect and decide what to do...
-- Murphy
On Mar 24, 2011, at 7:51 AM, Christian Esteve Rothenberg wrote:
Harry,
the problem is that the datapath flows do expire after 5 seconds of
inactivity. You can change this in the pyswitch flow install timeout
options.
You can also check that if you keep sending ping packets between the
hosts, the flow entries do not expire independent from the controller
connectivity (unless you opt to change the default behaviour of
switches after loosing the connection to the controller).
-Christian
On Thu, Mar 24, 2011 at 11:28, Harry <[email protected]
<mailto:[email protected]>> wrote:
Hi all,
Anyone could clear me this issue:
I'm playing with the *pyswitch* component built on NOX. I start a
single switch (ovsk switch) network in mininet with 3 hosts
(h2,h3,h4), then start NOX controller with pyswitch.
I ping from h2 to h3, log messages show that the controller
successfully installed datapath flow for the first 3 packets (ARP
& ICMP) between h2 & h3.
Then I exit the controller, of course, I still ping from h2 to h3
(because datapath flows have been installed on the switch).
*But when I restart the controller and do the ping h2->h3 again,
why does the controller reinstall the datapath flows on the
switch? The datapath flows on the switch seem to be cleared when
I restart the controller. *
Thank you very much!
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--
Christian
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Thanks Christian and Murphy,
I did control the flow install timeout and saw the different. However,
the main reason is as Murphy said.
@Murphy: I understand what you've wondered. Have you do any modification
to control the behavior of controller to Switch flow table at the first
time they connect?
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