So this warning is triggered when a packet was received on a switch port connected to another openflow switch, but there was no matching flow entry for the packet and thus it was sent up to nox. The message was initially logged with the thought that a packet would only reach an "internal" switch port if its flow had been permitted by the controller, in which case flow entries should have been installed in all switches en route, and thus internal switch ports would not receive non-matching packets.
That being said, the warning comes up fairly often for various reasons: 1. The naive flooding of broadcast packets without any installation of flow entries results in the packets being sent up to the controller by every internal switch port receiving them. 2. When a flow entry is first set up, there's a slight race condition in that the first hop switch could have already set up its entry and begun forwarding packets before the second hop has completed its installation of the new entry. The second hop switch will thus receive the packet, not see an entry for it, and thus send it up to the controller for a permission check. Neither of these occurrences however should result in any weird network behavior as the packet should still get forwarded on as expected. Natasha On Jul 16, 2008, at 11:05 PM, Glen Gibb wrote: > Hi all, > > What would trigger a "Buffer_id xxx at internal ap" message? > > Thanks, > Glen > > _______________________________________________ > nox-dev mailing list > [email protected] > http://noxrepo.org/mailman/listinfo/nox-dev_noxrepo.org _______________________________________________ nox-dev mailing list [email protected] http://noxrepo.org/mailman/listinfo/nox-dev_noxrepo.org
