I haven't really thought about it, but I think all of the basic "learning" forwarding components in POX have this same restriction. Getting around it would require implementing something additional (e.g., using one of the strategies I outlined earlier).
-- Murphy On Sep 12, 2013, at 1:36 AM, Dharani Kunnuru <[email protected]> wrote: > On Thu, Sep 12, 2013 at 1:21 PM, Murphy McCauley <[email protected]> > wrote: > In the future, please consider not dropping the list. > > > None of the components which ship with POX are intended for this use case, > but it can be done in several ways. For example... > > One straightforward approach would be to implement STP-over-OpenFlow. > Another is to have controllers communicate between each other to jointly > discover the whole network's topology (this is the approach taken by ONOS). > If you don't do controller assignment at random and instead have multiple > "islands", then you can do a two-level discovery (discovery within islands > and discovery between islands). > > There's a whole space of designs, and I'm not sure that there are any clear > universal winners. > > -- Murphy > > On Sep 12, 2013, at 12:21 AM, Dharani Kunnuru <[email protected]> > wrote: > >> Thank you for your reply.. >> >> Yes it is working for single controller case. I have tried with 3 modules >> forwarding.l2_learning, openflow.spanning_tree, openflow.dicovery. >> Forwarding is possible incase of loops also. >> >> The same i tried with multiple controllers. It is not working. >> >> I have created 4 switches as follows: >> >> s1-------s2 >> | | >> | | >> s3-------s4 >> >> connection between s3---s2 and s1---s4 are also there. >> >> I have assigned switches randomly under two controllers c1 & c2 . >> >> In this scenario, no two hosts are communicating. So , is there any way to >> make this work. >> >> please let me know the solution. >> >> >> On Thu, Sep 12, 2013 at 6:48 AM, Murphy McCauley <[email protected]> >> wrote: >> Most (or all?) of the forwarding components POX ships with will cause >> broadcast/flood storms when used on topologies with loops by themselves. >> This isn't a property of POX, but of the specific forwarding components. It >> can be resolved in multiple ways. One way is to disable flooding on some >> switch ports such that the flood-enabled ports form a spanning tree. The >> openflow.spanning_tree POX component implements this method in a way which >> is at least partially agnostic to the forwarding component. >> >> So the short answer is yes. If you, for example, run l2_learning and >> openflow.spanning_tree (the latter of which also requires >> openflow.discovery, if I recall correctly), forwarding should work even on >> topologies with loops. See the POX manual wiki and probably the >> openflow.spanning_tree docstring for more on this. >> >> -- Murphy >> >> On Sep 11, 2013, at 11:02 AM, Dharani Kunnuru <[email protected]> >> wrote: >> >>> Hello Everyone, >>> >>> I want to use POX controller to distributed control plane ( Logically >>> centralized but physically distributed) . And the topology iam going to use >>> should support loops? So, I want to know whether POX supports loops or not? >>> >>> I have tried with single controller, All hosts are not able to communicate >>> with each. I have read one post in this group >>> >>> http://lists.noxrepo.org/pipermail/pox-dev-noxrepo.org/2013-July/000834.html >>> >>> They mention some changes to switch to allow loops? So is it possible to >>> configure switch to allow loops?? >>> >>> Please some one reply me.. >>> >>> -- >>> K Dharani >> >> >> >> >> -- >> K Dharani > > > Sorry for breaking the list... > > And thank you for your reply.. > > > > > > There is restriction in floodlight controller like only one link is allowed > between the Openflow and non-Openflow islands. > > Like this, any kind of restrictions in POX. > Please let me know > -- > K Dharani
