H3C Technologies H3C S12500-X Series Switches - Manual (Page 9)

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{
Apply-Actions—Applies the specified actions in the action list immediately.
{
Clear-Actions—Clears all actions in the action set immediately.
{
Write-Actions—Modifies all actions in the action set immediately.
{
Goto-Table—Indicates the next MAC-IP 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. Then, 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.
• 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.
• Cookies—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 unmatched 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 with a number 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 a flow
table contains an action list, the OpenFlow switch immediately executes the actions for a copy of the
packet in this table.
Figure 3 OpenFlow forwarding workflow
Group table
The ability for a flow entry to point to a group enables OpenFlow to represent additional methods of
forwarding. A group table contains group entries.