Thanks Murphy for your detailed answer. Actually, I am working on NOX, and am interested to know how the NOX works in the following setup (For the sake of brevity I mentioned the simple topology in my last mail):
If 'n' Openflow switches are connected through some topology, and out of them only one OF switch is connected to NOX (assuming that in-band control only). In this setup, can NOX get the entire topology and is it possible to control all the switches through this single NOX controller. If the NOX is enough intelligent to guide other switches through the connected switch, I think this is possible, but I am not sure. Looking forward for your reply. Thanks, Ramana. On Mon, Jul 9, 2012 at 5:12 PM, Murphy McCauley <[email protected]>wrote: > On Jul 9, 2012, at 12:14 AM, Ramana Reddy wrote: > > Thanks for your reply. In the above setup, I believe that the other two > OF switches just actings as L2 learning switches, as they are not directly > connected to OF controller. If this is the case, how the OF switch ( the > one which > > is connected to Controller) inserts the rules in the other two OF > switches. > > A switch doesn't insert rules in other switches. Only controllers do > this. So I'm not sure what your thinking is here. > > If the two switches not connected to the controller are acting as learning > switches, that's because they have some "fail open" behavior where they > automatically do this if they can't contact their controller. > > > How in-band solves this problem. > > Any help is this regard is more helpful to understand the internal > operation of in-band control. > > I don't think there are any simple answers here. For one thing, in-band > control is not strictly defined -- it means different things to different > people and to different switches. > > With your simple topology, the answer may be relatively simple. If the > not-directly-connected switches expect to talk to the controller over a > vlan that's configured on the port that connects them to the directly > connected switch, you can probably just install a flow on the directly > connected switch to send that vlan to the controller. Then the satellite > switches should be able to reach the controller too. > > > As a sidenote, this doesn't really seem to be NOX related. You may find > the openflow-discuss mailing list or something more helpful. > > -- Murphy
