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Output port
If the output port of a Packet-out packet is the Flood or All reserved port, the switch processes the
packet as follows:
• When the output port is the Flood reserved port:
{ If the Packet-out packet has a VLAN tag, the switch broadcasts the packet within the VLAN.
{ If the Packet-out packet has no VLAN tag and the ingress port is a physical or logical port,
the switch tags the packet with the PVID of the ingress port. The switch then forwards the
packet within the VLAN.
{ If the Packet-out packet has no VLAN tag and the ingress port is the Controller reserved
port, the switch forwards the packet out all OpenFlow ports.
• When the output port is the All reserved port:
{ If the Packet-out packet has a VLAN tag, the switch broadcasts the packet within the VLAN.
{ If the Packet-out packet has no VLAN tag, the switch forwards the packet out of all
OpenFlow ports regardless of the ingress port type.
Packet-in messages restrictions
Processing VLAN tags
When sending a Packet-in packet to the controller, the switch processes the VLAN tag of the packet
as follows:
• If the VLAN tag of the packet is the same as the PVID of the ingress port, the switch removes
the VLAN tag.
• If the VLAN tag of the packet is different from the PVID of the ingress port, the switch does not
remove the VLAN tag.
Packet buffer
If a Packet-in message is sent to controller due to no matching flow entry, the switch supports
buffering the packet. The buffer size is 1K packets.
If a Packet-in message is sent to controller for other reasons, the switch does not support buffering
the packet. The switch must send the full packet to the controller, and the cookie field of the packet is
set to 0xFFFFFFFFFFFFFFFF.
LLDP frame matching
LLDP is used to perform topology discovery in an OpenFlow network. LLDP must be enabled
globally on a device and disabled on ports that belong to an OpenFlow instance. A switch sends a
LLDP frame to the controller through the Packet-in message when the following conditions exist:
• The port that receives the LLDP frame belongs to an OpenFlow instance.
• The flow tables in the OpenFlow instance have a flow entry that matches the LLDP frame (the
output port is the Controller reserved port).
Flow table modification messages restrictions
The flow table modification messages have the following restrictions for the table-miss flow entry and
common flow entries:
• Table-miss flow entry
{ The controller deploys the table-miss flow entry (the action is Drop) to an OpenFlow
instance after the OpenFlow instance is activated.
{ The controller cannot query the table-miss flow entry through Multipart messages.
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