4
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.
Figure 4
Components of a group entry
A group entry contains the following fields:
•
Group Identifier
—A 32 bit unsigned integer uniquely identifying the group.
•
Group Type
—Type of the group.
{
All
—Execute all buckets in the group. This type is used for multicast or broadcast forwarding.
{
Indirect
—Execute the one defined bucket in the group. This type is available in Release
2311P05 and later versions.
•
Counters
—Updated when packets are processed by a group.
•
Action Buckets
—An ordered list of action buckets, where each action bucket contains a set of
actions to execute and associated parameters.
Meter table
Meters enable OpenFlow to implement various simple QoS operations, such as rate-limiting. A group
table contains meter entries.
Figure 5
Components of a meter entry
A meter entry contains the following fields:
•
Meter Identifier
—A 32 bit unsigned integer uniquely identifying the meter.
•
Meter Bands
—Each meter can have one or more meter bands. Each band specifies the rate at
which the band applies and the way packets should be processed. If the current rate of packets
exceeds the rate of multiple bands, the band with the highest configured rate is used.
•
Counters
—Updated when packets are processed by a meter.
Figure 6
Components of a meter band
A meter band contains:
•
Band Type
—Defines how packets are processed. Packets that exceed the band rate are dropped.
•
Rate
—Used by the meter to select the meter band, defines the lowest rate at which the band can
apply.
•
Counters
—Updated when packets are processed by a band.
•
Type Specific Arguments
—Some band types have optional arguments.
