Output port for selected packets, if nonempty. Mutually exclusive
with .
Specifying a port for mirror output reserves that port exclusively
for mirroring. No frames other than those selected for mirroring
will be forwarded to the port, and any frames received on the port
will be discarded.
This type of mirroring is sometimes called SPAN.
Output VLAN for selected packets, if nonempty. Mutually exclusive
with .
The frames will be sent out all ports that trunk
, as well as any ports with implicit VLAN
. When a mirrored frame is sent out a
trunk port, the frame's VLAN tag will be set to
, replacing any existing tag; when it is
sent out an implicit VLAN port, the frame will not be tagged. This
type of mirroring is sometimes called RSPAN.
Please note: Mirroring to a VLAN can disrupt a network that
contains unmanaged switches. Consider an unmanaged physical switch
with two ports: port 1, connected to an end host, and port 2,
connected to an Open vSwitch configured to mirror received packets
into VLAN 123 on port 2. Suppose that the end host sends a packet on
port 1 that the physical switch forwards to port 2. The Open vSwitch
forwards this packet to its destination and then reflects it back on
port 2 in VLAN 123. This reflected packet causes the unmanaged
physical switch to replace the MAC learning table entry, which
correctly pointed to port 1, with one that incorrectly points to port
2. Afterward, the physical switch will direct packets destined for
the end host to the Open vSwitch on port 2, instead of to the end
host on port 1, disrupting connectivity. If mirroring to a VLAN is
desired in this scenario, then the physical switch must be replaced
by one that learns Ethernet addresses on a per-VLAN basis. In
addition, learning should be disabled on the VLAN containing mirrored
traffic. If this is not done then intermediate switches will learn
the MAC address of each end host from the mirrored traffic. If
packets being sent to that end host are also mirrored, then they will
be dropped since the switch will attempt to send them out the input
port. Disabling learning for the VLAN will cause the switch to
correctly send the packet out all ports configured for that VLAN. If
Open vSwitch is being used as an intermediate switch, learning can be
disabled by adding the mirrored VLAN to
in the appropriate table or tables.