H3C Technologies H3C S6800 Series Switches - Manual (Page 30)

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Packet-in messages restrictions
Processing VLAN tags
When sending a packet-in message to the controller, the switch processes the VLAN tag of the packet
contained in the packet-out message 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 contained in the packet-in message. 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 contained in the packet-in message. 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 OpenFlow instances. 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 from the controller 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.
{
The controller cannot modify the table-miss flow entry through the Modify request. The controller
can only modify the table-miss flow entry through the Add request.
{
The controller can modify or delete the table-miss flow entry only through the strict version of the
Modify or Delete request. The controller cannot modify or remove the table-miss flow entry
through the non-strict version of the Modify or Delete request despite that the match fields are
wildcarded.
• Common flow entries
The controller cannot modify or remove all common flow entries through the non-strict version of
the Modify or Delete request despite that the match fields are wildcarded.