Thanks for your quick and nice reply!

JW

On Fri, Mar 26, 2010 at 2:26 PM, Martin Casado <[email protected]> wrote:

> Inline:
>
>
>
>>
>> On Fri, Mar 26, 2010 at 9:56 AM, Martin Casado <[email protected]<mailto:
>> [email protected]>> wrote:
>>
>>    Inline:
>>
>>
>>        Dear martin,
>>
>>        Thanks for your reply. We just think when the network
>>        environment contains more than 2 NOXs, what is the behavior
>>        between them? So, NOX do not do the load balance currently?
>>
>>    Correct, Nox does not support multiple instances working together.
>>     For that, you will have to extend Nox.
>>
>> If we want to modify, which source code is the good starting point?
>>
>
> Oh boy, that depends entirely on what you want to do.  To begin with, I
> would suggest building a simple client/server component using twisted in
> python in order to exchange state between controllers.
>
>
>
>>
>>        By the way, We still have some questions which need to your help.
>>        1) What is the process that NOX want to build its controlled
>>        OpenFlow switches topology? NOX will send an event to notify
>>        all controlled OpenFlow switches, then all OpenFlow switches
>>        will send LLDP out from their owned ports to all connected
>>        switches?
>>
>>    Right.  Nox sends out LLDP packets from every switch port and then
>>    listens for incoming LLDP packets on neighbor switches to
>>    determine the topology.
>>
>> This means that the LLDP packets are sent out from NOX? When LLDP packets
>> arrived on every switches which connect to NOX, every switch will redirect
>> LLDP packets to its connected switches?
>>
>
> Yes, Nox sends LLDP packets out of every port on every switch.
>
>
>
>>        2) The discoveried topology will be stored on NOX?
>>
>>    Correct.
>>
>>        3) Support we have a network topology, which showed below,
>>        these OpenFlow switches are all controlled by one NOX. What do
>>        the NOX write into the flowtables of these OpenFlow switches
>>        when user ping host2 from host1?
>>
>>        host1 -- ofsw1 -------  ofsw2
>>                      |                  |
>>                      |                  |
>>                   ofsw3 -------  ofsw4  --  host2
>>
>>
>>    Nox doesn't support topologies with loops (though there are a
>>    number of spanning tree implementations which have been ported to
>>    it) so this would not work.  However, if there wasn't a loop, then
>>    nox would set up flows for the ARP and ICMP packets in both
>>    directions.
>>
>> We assume to remove the link between ofsw1 and ofsw2 in the above topology
>> (no loop topology). NOX knows that ofsw1 connect to ofsw3, ofsw3 connect to
>> ofsw4 by LLDP packets? If it is correct, will NOX write ofsw3's information
>> into ofsw1, such as which port of ofsw1 connects to ofsw3 port? There will
>> have the similar information on ofsw3 and ofsw4?
>>
> This depends on what applications are running.  If you are running routing
> then yes, Nox discovers the topology via LLDP packets and stores the
> information in the topology component.  So Nox knows, internally, that ofsw1
> is connect to ofsw3, ofsw3 is connect to ofsw1 and ofsw4, and ofsw4 is
> connected to ofsw3 and ofsw2.
>
> .m
>
>>
>> Bests,
>>
>> JW
>>
>>    .martin
>>
>>
>>        We really appreciate to all the help you gave us.
>>        Best,
>>
>>        JW
>>
>>        On Fri, Mar 26, 2010 at 5:55 AM, Martin Casado
>>        <[email protected] <mailto:[email protected]>
>>        <mailto:[email protected] <mailto:[email protected]>>> wrote:
>>
>>           Hi JW,
>>
>>           Nox was not built to support coordination between two
>>        instances.
>>            Why don't control both switches from the same Nox process?
>>
>>           .martin
>>
>>               Dear all,
>>
>>               We just join the world of OpenFlow and NOX lately.
>>        Everything
>>               for us is new and also doesn't know how to start.
>>        Currently,
>>               we have built the enviroment which contains 1 NOX (nox1), 1
>>               OpenFlow switch with NetFPGA (ofsw1), and 2 hosts which
>>               connect to ofsw1. After installing, we got some
>>        quesions about
>>               it. Could someone could help us?
>>
>>               (current)
>>               nox1 -- ofsw1
>>                            |--- host1
>>                            |--- host2
>>
>>               (suppose)
>>               nox1 -- ofsw1 ----------------- ofsw2 -- nox2
>>                            |--- host1
>>                            |--- host2
>>
>>               1. Suppose we add 1 OpenFlow switch (ofsw2) and 1 NOX
>>        (nox2),
>>               let this ofsw2 connects to nox2 and sw1. The LLDP will let
>>               nox1 discover ofsw1, how let nox1 also discovery ofsw2?
>>               2. Does nox1 could discover nox2?
>>               3. The packages between ofsw1 and ofsw2 are using OpenFlow
>>               protocol? And how about nox1 and nox2?
>>
>>               Thanks
>>               Bests,
>>
>>               JW
>>
>>  ------------------------------------------------------------------------
>>
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>>
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>>
>>
>>
>>
>>
>
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