Packet listeners display

The controller applications (and SDN applications) register packet listeners with the controller. The order of processing an incoming packet is determined by the roles (Advisor, then Director, then Observer), and then altitudes within a role (in decreasing value, with 0 the lowest altitude). An incoming packet (PacketListenerRole) is wrapped in a Message Context (which also holds a Packet-Out reply) which is passed to each packet listener in turn.

Packet listeners display details

The packet listeners screen displays the packet listeners that are currently running on the controller.

Screen componentDescription

Refreshes the information on the screen.

PacketListener Role

The PacketListener Role is one of the following:

ADVISORExamines the incoming packet. Might add processing hints to the message context, but does not modify the packet out message.
DIRECTORProcesses the packet. Might add actions or instructions to the packet-out message. Can instruct the controller to block the packet, or to send the packet out.
OBSERVERA passive observer who might examine the incoming packet and any packet-out response.

Packets are given to packet listeners with role of ADVISOR first, DIRECTOR second, and OBSERVER third. Every packet listener is guaranteed to see the packet-in message. Depending on the action taken by higher altitude Directors, a lower altitude Director might be too late to influence the packet processing.


The weight or priority this packet listener should have relative to other packet listeners that have the same role. The controller gives packet listeners with higher numbers priority over packet listeners with lower numbers.

Average (ms)

The average time, in milliseconds, that the packet listener spent processing a packet.

# Samples

The number of packets processed by that packet listener since the packet listener registered.