On Wed, Mar 4, 2015 at 4:02 PM, Ben Pfaff <b...@nicira.com> wrote: > On Wed, Mar 04, 2015 at 11:10:49AM -0600, Cheng Jin wrote: > > On Tue, Mar 3, 2015 at 3:03 PM, Ben Pfaff <b...@nicira.com> wrote: > > > > > On Tue, Mar 03, 2015 at 12:25:20PM -0600, Cheng Jin wrote: > > > > I have a problem with updating OVS' MAC learning table, when it is > in the > > > > 'standalone' mode running like a legacy Ethernet bridge. > > > > > > > > The switch has an entry to a destination, including the destination > MAC > > > > (say, 00:00:00:00:00:01), an output port (say, 1), VLAN, and Age. > > > However, > > > > the switch sometimes does not update the entry, when it receives a > packet > > > > from the same destination (still 00:00:00:00:00:01) but from a new > > > incoming > > > > port (say, 2). Does someone know what may cause this issue? > > > > > > > > The MAC learning table is supposed to be updated once receiving a > packet. > > > > Does OVS do some optimization to process the packets so that the > learning > > > > table may not get updated when the packet rate is high? > > > > > > The optimization that OVS does should only affect cases where a MAC > > > would otherwise quickly bounce back and forth between a number of > > > learned ports. > > > > > > Is there anything unusual in your setup? Can you reproduce this with > > > a simple setup? > > > > > > > We tried a simple setup which has only three switches forming a triangle > > (VLAN set up to avoid loop), and two hosts connect with two "standalone" > > switches. > > > > The MAC learning table is allowed to stabilize (we send no traffic) and > > then we send a packet from a source MAC that already exists in the MAC > > table but which comes on another port than the one registered in the > table. > > We are checking how soon does the switch adapt. We don't do back and > forth > > changes often so the optimization should not happen. > > I ran a test just now and could not reproduce the problem. > > I connected two VMs, A and B, through OVS running in a third VM C. In > C, I ran "watch -n.1 ovs-appctl fdb/show br0" to observe changes in > the MAC learning table. I ran a "ping" for a few seconds and saw that > the MAC learning table was initialized as expected. Then I killed the > ping and ran "ifconfig eth0 hw ether <address>" in each of the VMs, in > each case using the other VM's MAC address, effectively swapping MAC > addresses. Then I reran the ping. The displayed ports for those > MACs immediately flipped. I ran the experiment a few times. > > Then I tried turning up the log level for ofproto_dpif_xlate and > observed the kinds of messages I expected, e.g.: >
How to turn up the log level for ofproto_dpif_xlate to observe these messages? > > 2015-03-04T22:00:43Z|00002|ofproto_dpif_xlate(handler5)|DBG|bridge br0: > learned that 50:54:00:00:00:05 is on port eth0 in VLAN 0 > 2015-03-04T22:00:43Z|00004|ofproto_dpif_xlate(handler5)|DBG|bridge br0: > learned that 50:54:00:01:00:05 is on port eth1 in VLAN 0 > 2015-03-04T22:00:55Z|00005|ofproto_dpif_xlate(handler5)|DBG|bridge br0: > learned that 50:54:00:01:00:05 is on port eth0 in VLAN 0 > 2015-03-04T22:00:55Z|00006|ofproto_dpif_xlate(handler5)|DBG|bridge br0: > learned that 50:54:00:00:00:05 is on port eth1 in VLAN 0
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