Hi,
I imagined that the steps were like you mentioned... well,
Firstly, s3 send packet_in to c0, and another moment s2 send packet_in
to s3that send to
c0...
Well, as you mentioned earlier, I need to set initial flow entries, that is,
I think that is the flow from s2 to s3
,.. one time initiated the topology, like the linear topology, the initial
flow entries should be installed, I think..
so that initial flow entries must be configured in the topology script? or
maybe from CLI via dpctl?
thank you,
On Thu, Oct 20, 2011 at 11:31, Kyriakos Zarifis kyr.zari...@gmail.comwrote:
Yes, that is possible. This is where in-band vs out-of-band control comes
to play: If the physical topology looks exactly like what you described then
control of sw1 can only been done in-band (meaning, the control packets are
using the same links as the data packets). In order for that to be possible,
there need to be some initial flow entries in the intermediate switches to
allow a remote switch to connect to the controller. I don't think there is a
standardized way to set up in-band control, but I am guessing a simple
version would be something like:
- s3 connects to c0
- the controller receives packet_in from s3, which originated in s2 while it
tried to connect
- c0 sets a flow on s3 that allows traffic from s2 to reach it
- at this point s2 and s3 are connected to the controller
- sw2 picks up packet from s1 and sends packet_in to c0
OpenvSwitch has a pretty sophisticated approach to in-band control. If
you're interested you can take a look here :
http://openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=blob_plain;f=DESIGN
(look for in-band)
On Thu, Oct 20, 2011 at 5:39 AM, scolfield kscolfi...@gmail.com wrote:
Hi,
Thanks for your reply.
It's possible openflow messages across several switches until achieve the
controller?
Such as host - sw1 - sw2 - sw3 - c0 or in a reverse way in linear
topology?
Consider that the host packet need to achieve a server connected to sw3and
there are only
one controller linked to one switch.
--
scolf
On Thu, Oct 20, 2011 at 06:32, Kyriakos Zarifis kyr.zari...@gmail.comwrote:
Hi,
pyswitch itself is really not aware of any topology. It only stores state
that is relevant to switches separately (i.e. it stores a mapping of mac
addresses to local ports for a switch).
Now, whether a control packet (like a packet_in) will reach the
controller if it's not directly physically connected to it is another issue,
and is irrelevant to what NOX application (eg pyswitch) is running. Switches
are connected to the controller through a separate control channel, so as
long as this channel has been established (which is when the switch first
connects to NOX), then the packet_ins will find their way to NOX through
that (irrespective of dataplane connectivity, which is established by NOX
applications)
(another thing to consider is whether the switch-controller connection is
in-bound/out-of-bound)
Does this make sense?
On Wed, Oct 19, 2011 at 5:20 PM, scolfield kscolfi...@gmail.com wrote:
Hi,
The pyswitch example can learn topology of networks? Such as a
corporation architecture when
there are hierarchical switches interconnected one to another creating
several layers of switches,
at this case, the one openflow controller connected to two distinct
switches, can learn which ports
to send a ping packets, for example? The packet in messages will be
forwarded automatically through
switches until reach a controller?
--
scolfield
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