Thanks a lot
On Fri, Mar 29, 2013 at 1:07 PM, Ben Pfaff <[email protected]> wrote: > On Fri, Mar 29, 2013 at 01:05:16PM +0800, Kris zhang wrote: > > So my question is why the network speed is slow when use vlan in OVS? > > There's a huge section in the FAQ about VLANs. Please read it. > > Some relevant parts: > > Q: VLANs don't work. > > A: Many drivers in Linux kernels before version 3.3 had VLAN-related > bugs. If you are having problems with VLANs that you suspect to be > driver related, then you have several options: > > - Upgrade to Linux 3.3 or later. > > - Build and install a fixed version of the particular driver > that is causing trouble, if one is available. > > - Use a NIC whose driver does not have VLAN problems. > > - Use "VLAN splinters", a feature in Open vSwitch 1.4 and later > that works around bugs in kernel drivers. To enable VLAN > splinters on interface eth0, use the command: > > ovs-vsctl set interface eth0 > other-config:enable-vlan-splinters=true > > For VLAN splinters to be effective, Open vSwitch must know > which VLANs are in use. See the "VLAN splinters" section in > the Interface table in ovs-vswitchd.conf.db(5) for details on > how Open vSwitch infers in-use VLANs. > > VLAN splinters increase memory use and reduce performance, so > use them only if needed. > > - Apply the "vlan workaround" patch from the XenServer kernel > patch queue, build Open vSwitch against this patched kernel, > and then use ovs-vlan-bug-workaround(8) to enable the VLAN > workaround for each interface whose driver is buggy. > > (This is a nontrivial exercise, so this option is included > only for completeness.) > > It is not always easy to tell whether a Linux kernel driver has > buggy VLAN support. The ovs-vlan-test(8) and ovs-test(8) utilities > can help you test. See their manpages for details. Of the two > utilities, ovs-test(8) is newer and more thorough, but > ovs-vlan-test(8) may be easier to use. > > Q: VLANs still don't work. I've tested the driver so I know that it's OK. > > A: Do you have VLANs enabled on the physical switch that OVS is > attached to? Make sure that the port is configured to trunk the > VLAN or VLANs that you are using with OVS. > > Q: Outgoing VLAN-tagged traffic goes through OVS to my physical switch > and to its destination host, but OVS seems to drop incoming return > traffic. > > A: It's possible that you have the VLAN configured on your physical > switch as the "native" VLAN. In this mode, the switch treats > incoming packets either tagged with the native VLAN or untagged as > part of the native VLAN. It may also send outgoing packets in the > native VLAN without a VLAN tag. > > If this is the case, you have two choices: > > - Change the physical switch port configuration to tag packets > it forwards to OVS with the native VLAN instead of forwarding > them untagged. > > - Change the OVS configuration for the physical port to a > native VLAN mode. For example, the following sets up a > bridge with port eth0 in "native-tagged" mode in VLAN 9: > > ovs-vsctl add-br br0 > ovs-vsctl add-port br0 eth0 tag=9 vlan_mode=native-tagged > > In this situation, "native-untagged" mode will probably work > equally well. Refer to the documentation for the Port table > in ovs-vswitchd.conf.db(5) for more information. >
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