Hi, Murphy, I think I have send packet_out for every packet_in....
I just added more statements to print out logs, it shows that a lot of IPV6 multicast packets going through my network ...will that overwhelm the buffer? For the second possibility, do you mean I set the limitation to a smaller value so that every packet would be buffered? can you give some hint on doing this? Best, Nan On Tue, Nov 19, 2013 at 2:04 PM, Murphy McCauley <murphy.mccau...@gmail.com>wrote: > I'm aware of two possibilities. > > The first is that your switch is out of buffer space/IDs. This can happen > particularly if you are ignoring packet-ins in your controller. You may be > better off sending a packet-out that references the buffer_id but has no > actions; this way the switch will deallocate the buffer (various examples > in POX do this; e.g., l2_learning, I believe). > > The second is that there's always a size limit of how much of a packet the > switch will send to the controller. There's a single limit for packets > which miss the table entirely, and every send-to-controller action has its > own limit. If a packet is larger than this limit, the controller buffers > the packet locally and sends a truncated version to the controller. > However, if the packet is smaller than the limit, I believe OVS will > simply send the entire packet to the controller *and not buffer it*. In > POX, the "maximum length" for output actions to send to the controller is > the full size of the packet, but you can set it to be smaller. > > I'll also note that POX's packet_out and flow_mod have special cases to > make it easier to deal with the fact that you may have either case (a > buffer ID or a full packet). The flow_mod one in particular isn't always > ideal, but they work a lot of the time. > > -- Murphy > > On Nov 19, 2013, at 6:08 AM, Nan Zhu <zhunanmcg...@gmail.com> wrote: > > > Hi, all > > > > I'm developing some controller with POX, > > > > When I test it with mininet (--switch ovsk), I found that I will receive > some packet_in which has a buffer_id with the value of None? > > > > Anyone had this problem before? obviously it is caused by my controller, > I used other code to test, this type of packet never appear > > > > What can be the reason of that? > > > > Best, > > > > Nan > > > > > >
