H3C Technologies H3C S6800 Series Switches - Manual (Page 12)

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{
Write-Metadata—Modifies packets between two flow tables if multiple flow tables exist.
{
Goto-Table—Indicates the next flow table in the processing pipeline.
Actions are executed in one of the following ways:
{
Action Set—When the instruction set of a flow entry does not contain a Goto-Table instruction,
pipeline processing stops and the actions in the action set are executed. An action set contains
a maximum of one action of each type.
{
Action List—The actions in the action list are executed immediately in the order specified by the
action list. The effect of those actions is cumulative.
Actions include the following types:
{
(Required.) Output—The Output action forwards a packet to the specified OpenFlow port.
OpenFlow switches must support forwarding packets to physical ports, logical ports, and
reserved ports.
{
(Required.) Drop—No explicit action exists to represent drops. Packets whose action sets have
no output actions are dropped. Typically, packets are dropped due to empty instruction sets,
empty action sets, or the executing a Clear-Actions instruction.
{
(Required.) Group—Process the packet through the specified group. The exact interpretation
depends on group type.
{
(Optional.) Set-Queue—The Set-Queue action sets the queue ID for a packet. When the packet
is forwarded to a port by the output action, the packet is assigned to the queue attached to this
port for scheduling and forwarding. The forwarding behavior is dictated by the configuration of
the queue and provides basic QoS support.
{
(Optional.) Set-Field—The Set-Field actions are identified by their field type and modify the
values of corresponding header fields in the packet. Set-Field actions are always applied to the
outermost header. For example, a Set VLAN ID action always sets the ID of the outermost VLAN
tag.
• Timeouts—Maximum amount of idle time or hard time for the flow entry.
{
idle time—The flow entry is removed when it has matched no packets during the idle time.
{
hard time—The flow entry is removed when the hard time timeout is exceeded, whether or not
it has matched packets.
• Cookie—Flow entry identifier specified by the controller.
Table-miss flow entry
Every flow table must support a table-miss flow entry to process table misses. The table-miss flow entry
specifies how to process packets that were not matched by other flow entries in the flow table.
The table-miss flow entry wildcards all match fields (all fields omitted) and has the lowest priority 0.
The table-miss flow entry behaves in most ways like any other flow entry.
OpenFlow pipeline
The OpenFlow pipeline processing defines how packets interact with flow tables contained by a switch.
The flow tables of an OpenFlow switch are sequentially numbered, starting at 0. The packet is first
matched with flow entries of the first flow table, which is flow table 0. A flow entry can only direct a
packet to a flow table number that is greater than its own flow table number.
When a packet matches a flow entry, the OpenFlow switch updates the action set for the packet and
passes the packet to the next flow table. In the last flow table, the OpenFlow switch executes all actions
to modify packet contents and specify the output port for packet forwarding. If the instruction set of one