Controller roles
Equal
Master
Slave
Equal
Equal is the default role for a controller. The controller has full access to the switch and is equal to other controllers in the same role receiving all asynchronous messages from the switch (such as packet-in, flow-removed). Controller-to-switch commands are sent and modified within this role.
Slave
A Slave controller has read-only access to the switch. The controller cannot receive switch asynchronous messages except for Port-status messages. The controller is denied execution of the controller-to-switch commands: OFPT_PACKET_OUT, OFPT_FLOW_MOD, OFPT_GROUP_MOD, OFPT_PORT_MOD and OFPT_TABLE_MOD.
Master
The Master controller has full read-write access to the switch. Only one controller can be the Master at a given time. When the role of a controller is changed to Master, the switch changes all other controllers that it connects to, to a Slave role.
Syntax
To know the roles of controllers that a switch is connected to, use the following command:
show openflow instance <instance-name>
Example
switch(openflow)# show openflow instance test Configured OF Version : 1.3 only Negotiated OF Version : 1.3 Instance Name : test Data-path Description : test Administrator Status : Enabled Member List : VLAN 3 Pipeline Model : Standard Match Listen Port : 6633 Operational Status : Up Operational Status Reason : NA Datapath ID : 000340a8f09e8600 Mode : Active Flow Location : Hardware and Software No. of Hardware Flows : 6 No. of Software Flows : 4 Hardware Rate Limit : 0 kbps Software Rate Limit : 100 pps Conn. Interrupt Mode : Fail-Secure Maximum Backoff Interval : 60 seconds Probe Interval : 10 seconds Hardware Table Miss Count : NA No. of Software Flow Tables : 1 Egress Only Ports : None Table Model : Policy Engine and Software Source MAC Group Table : Disabled Destination MAC Group Table : Disabled Controller Id Connection Status Connection State Secure Role ------------- ----------------- ---------------- ------ ------ 1 Connected Active No Slave 2 Connected Active No Master