The libvirt virtual networking allows setting of the forward-delay parameter. This is the delay the kernel inserts before it starts forwarding traffic when a guest VIF is added to a bridge. The default network config sets this to zero, and previously we had a bug where we accidentally called brSetForwardDelay() based on the STP parameter which was zero, so we did in fact have a forward delay of 0 as desired. Rich then fixed this bug, and thus we no longer accidentally call the brSetForardDelay() method. Unfortuntely the place where we *do* delibrately call it is conditionalized on if (network->def->delay So if you set a forward delay of zero, we never explicitly set this on the bridge. Thus the kernel's default setting applies which is 15 seconds. The fix is trivial - just remove the conditional. So previously you could see traffic forwaarding delayed by the kernel for 30 seconds Aug 1 11:34:16 t60wlan kernel: device vnet0 entered promiscuous mode Aug 1 11:34:16 t60wlan kernel: virbr0: port 1(vnet0) entering listening state Aug 1 11:34:31 t60wlan kernel: virbr0: port 1(vnet0) entering learning state Aug 1 11:34:46 t60wlan kernel: virbr0: topology change detected, propagating Aug 1 11:34:46 t60wlan kernel: virbr0: port 1(vnet0) entering forwarding state Now it applies immediately Aug 1 11:40:07 t60wlan kernel: device vnet0 entered promiscuous mode Aug 1 11:40:07 t60wlan kernel: virbr0: port 1(vnet0) entering listening state Aug 1 11:40:07 t60wlan kernel: virbr0: port 1(vnet0) entering learning state Aug 1 11:40:07 t60wlan kernel: virbr0: topology change detected, propagating Aug 1 11:40:07 t60wlan kernel: virbr0: port 1(vnet0) entering forwarding state Daniel Index: src/qemu_driver.c =================================================================== RCS file: /data/cvs/libvirt/src/qemu_driver.c,v retrieving revision 1.98 diff -u -r1.98 qemu_driver.c --- src/qemu_driver.c 30 Jul 2008 09:20:19 -0000 1.98 +++ src/qemu_driver.c 1 Aug 2008 10:46:36 -0000 @@ -1480,8 +1480,7 @@ } - if (network->def->delay && - (err = brSetForwardDelay(driver->brctl, network->def->bridge, network->def->delay))) { + if ((err = brSetForwardDelay(driver->brctl, network->def->bridge, network->def->delay))) { qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR, _("failed to set bridge forward delay to %ld"), network->def->delay); -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|