Hi Bertrand, below is my understanding, a beginner myself so trying to figure it out as well. Perhaps it is more obvious if you use a linear topology involve multiple switches. For example:
mininet@mininet-vm:~$ sudo mn --topo linear,3 --mac --switch ovsk --controller remote <skip> mininet> net c0 s1 lo: s1-eth1:h1-eth0 s1-eth2:s2-eth2 s2 lo: s2-eth1:h2-eth0 s2-eth2:s1-eth2 s2-eth3:s3-eth2 s3 lo: s3-eth1:h3-eth0 s3-eth2:s2-eth3 h1 h1-eth0:s1-eth1 h2 h2-eth0:s2-eth1 h3 h3-eth0:s3-eth1 mininet> So each switch has one host connected to each and has one link connected to the next switch. So you would see that each Mac-To-Port differs from each switch. In OF, each switch is identified by DPID. So regardless of which controller you use, the statement make sense. You are right, In POX, each time a switch connects it creates an associated connection object if you are using their core object. I don't know enough about other controllers to comment, but certainly makes it nice. mininet@mininet-vm:~/pox$ ./pox.py log.level --DEBUG forwarding.l2_learning py <skip> POX> INFO:openflow.of_01:[00-00-00-00-00-02 1] connected DEBUG:forwarding.l2_learning:Connection [00-00-00-00-00-02 1] INFO:openflow.of_01:[00-00-00-00-00-01 2] connected DEBUG:forwarding.l2_learning:Connection [00-00-00-00-00-01 2] INFO:openflow.of_01:[00-00-00-00-00-03 3] connected DEBUG:forwarding.l2_learning:Connection [00-00-00-00-00-03 3] POX> for con in core.openflow.connections: ... print con, con.dpid ... [00-00-00-00-00-01 2] 1 [00-00-00-00-00-02 1] 2 [00-00-00-00-00-03 3] 3 POX> Hope it helps. Eric On Apr 14, 2013, at 2:39 PM, Bertrand Bonnefoy-Claudet <bertran...@gmail.com> wrote: > Hello, > > I've been through the tutorial up to the multiple switches part > (http://www.openflow.org/wk/index.php/OpenFlow_Tutorial#Support_Multiple_Switches) > and I don't understand what is meant by the following sentence: > > Now, modify your switch so that it stores a MAC-to-port table for each > DPID. > > First I think I haven't come across any mention of what a DPID is > (though I figured that out) and my controller seems to do the job very > well already (POX creates one instance of the Tutorial class per > switch, each having its own MAC table). > > Maybe it is because it is needed for other controllers and not the one > I used (POX). In that case, maybe that would be worth mentioning? > > Anyway, so far that's a great tutorial. > > Thanks, > -- > Bertrand > _______________________________________________ > openflow-discuss mailing list > openflow-discuss@lists.stanford.edu > https://mailman.stanford.edu/mailman/listinfo/openflow-discuss _______________________________________________ openflow-discuss mailing list openflow-discuss@lists.stanford.edu https://mailman.stanford.edu/mailman/listinfo/openflow-discuss
