From 717e7c8d1d9715f7177b7bf32c3158a8cca503d8 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Mon, 6 Aug 2012 15:41:37 -0700 Subject: [PATCH] FAQ: Add section on basic configuration. Signed-off-by: Ben Pfaff --- FAQ | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) diff --git a/FAQ b/FAQ index 4658bb98..ae904f19 100644 --- a/FAQ +++ b/FAQ @@ -168,6 +168,122 @@ A: Tunnel and patch virtual ports are not supported, as described in the may not be transmitted. +Basic Configuration +------------------- + +Q: How do I configure a port as an access port? + +A: Add "tag=VLAN" to your "ovs-vsctl add-port" command. For example, + the following commands configure br0 with eth0 as a trunk port (the + default) and tap0 as an access port for VLAN 9: + + ovs-vsctl add-br br0 + ovs-vsctl add-port br0 eth0 + ovs-vsctl add-port br0 tap0 tag=9 + + If you want to configure an already added port as an access port, + use "ovs-vsctl set", e.g.: + + ovs-vsctl set port tap0 tag=9 + +Q: How do I configure a port as a SPAN port, that is, enable mirroring + of all traffic to that port? + +A: The following commands configure br0 with eth0 and tap0 as trunk + ports. All traffic coming in or going out on eth0 or tap0 is also + mirrored to tap1; any traffic arriving on tap1 is dropped: + + ovs-vsctl add-br br0 + ovs-vsctl add-port br0 eth0 + ovs-vsctl add-port br0 tap0 + ovs-vsctl add-port br0 tap1 \ + -- --id=@p get port tap1 \ + -- --id=@m create mirror name=m0 select-all=true output-port=@p \ + -- set bridge br0 mirrors=@m + + To later disable mirroring, run: + + ovs-vsctl clear bridge br0 mirrors + +Q: How do I configure a VLAN as an RSPAN VLAN, that is, enable + mirroring of all traffic to that VLAN? + +A: The following commands configure br0 with eth0 as a trunk port and + tap0 as an access port for VLAN 10. All traffic coming in or going + out on tap0, as well as traffic coming in or going out on eth0 in + VLAN 10, is also mirrored to VLAN 15 on eth0. The original tag for + VLAN 10, in cases where one is present, is dropped as part of + mirroring: + + ovs-vsctl add-br br0 + ovs-vsctl add-port br0 eth0 + ovs-vsctl add-port br0 tap0 tag=10 + ovs-vsctl \ + -- --id=@m create mirror name=m0 select-all=true select-vlan=10 \ + output-vlan=15 \ + -- set bridge br0 mirrors=@m + + To later disable mirroring, run: + + ovs-vsctl clear bridge br0 mirrors + + Mirroring to a VLAN can disrupt a network that contains unmanaged + switches. See ovs-vswitchd.conf.db(5) for details. Mirroring to a + GRE tunnel has fewer caveats than mirroring to a VLAN and should + generally be preferred. + +Q: Can I mirror more than one input VLAN to an RSPAN VLAN? + +A: Yes, but mirroring to a VLAN strips the original VLAN tag in favor + of the specified output-vlan. This loss of information may make + the mirrored traffic too hard to interpret. + + To mirror multiple VLANs, use the commands above, but specify a + comma-separated list of VLANs as the value for select-vlan. To + mirror every VLAN, use the commands above, but omit select-vlan and + its value entirely. + + When a packet arrives on a VLAN that is used as a mirror output + VLAN, the mirror is disregarded. Instead, in standalone mode, OVS + floods the packet across all the ports for which the mirror output + VLAN is configured. (If an OpenFlow controller is in use, then it + can override this behavior through the flow table.) If OVS is used + as an intermediate switch, rather than an edge switch, this ensures + that the RSPAN traffic is distributed through the network. + + Mirroring to a VLAN can disrupt a network that contains unmanaged + switches. See ovs-vswitchd.conf.db(5) for details. Mirroring to a + GRE tunnel has fewer caveats than mirroring to a VLAN and should + generally be preferred. + +Q: How do I configure mirroring of all traffic to a GRE tunnel? + +A: The following commands configure br0 with eth0 and tap0 as trunk + ports. All traffic coming in or going out on eth0 or tap0 is also + mirrored to gre0, a GRE tunnel to the remote host 192.168.1.10; any + traffic arriving on gre0 is dropped: + + ovs-vsctl add-br br0 + ovs-vsctl add-port br0 eth0 + ovs-vsctl add-port br0 tap0 + ovs-vsctl add-port br0 gre0 \ + -- set interface gre0 type=gre options:remote_ip=192.168.1.10 \ + -- --id=@p get port gre0 \ + -- --id=@m create mirror name=m0 select-all=true output-port=@p \ + -- set bridge br0 mirrors=@m + + To later disable mirroring and destroy the GRE tunnel: + + ovs-vsctl clear bridge br0 mirrors + ovs-vcstl del-port br0 gre0 + +Q: Does Open vSwitch support ERSPAN? + +A: No. ERSPAN is an undocumented proprietary protocol. As an + alternative, Open vSwitch supports mirroring to a GRE tunnel (see + above). + + Configuration Problems ---------------------- -- 2.30.2