Correct Answer: D

Per-flow meters OpenFlow 1.3 brings support for per-flow meters. These can be attached to flow entries and can measure and control the rate of packets. One of the main applications of perflow meters is to rate limit packets sent to the controller.

Reference: Production-ready SDN with OpenFlow 1.3

http://h17007.www1.hp.com/docs/interop/2013/37958_HPN_SDN_Openflow_Brief_042913_lo.pdf (page 2)

Correct Answer: C

The controller with the highest priority.

Once a team is configured, the configuration and monitoring of team members and their associated OpenFlow switches is performed by the team manager. If the team manager goes down, the controller with the next highest priority in the team configuration becomes the team manager.

Note: Team Management Each controller belonging to a team is a team member. To centralize team management and control, one controller is designated as the team manager. Teaming is configured on one controller and is automatically

propagated to the other controllers in the team, regardless of which controller becomes the team manager.

Reference: HP VAN SDN Controller Administrator Guide

Correct Answer: A

Note:

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The PacketIn message is a way for the switch to send a captured packet to the controller. There are two reasons why this might happen; there could be an explicit action as a result of a match asking for this behavior, or from a miss in the match tables, or a ttl error.

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Flowchart detailing packet flow through an OpenFlow switch.

Reference: OpenFlow Switch Specification Version 1.3.1

Correct Answer: D

OSGi was thus selected to allow elasticity of applications. The applications can be dynamically introduced and dynamically removed from a running environment without having to shut down the whole controller and then restart it. Using a network analogy again, the applications are "hot- swappable".

Reference: HP Virtual Application Networks SDN Controller Technical Solution Guide http://www8.hp.com/ h20195/v2/GetPDF.aspx%2Fc04219919.pdf (page 11 and 12)

Correct Answer: A

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Failover (step 1)

ROS (role orchestration service) triggers the failover operation in two cases:

/ Controller failure:

/ Device disconnect:

The ROS instance in a controller is notified of a communication failure with network device(s) through the

Controller Service notifications. It instantly communicates with all ROS instances in the team to determine

if the network device(s) in question are still connected to any of the backup (slave) controllers within the

team. If that is the case, it elects one of the slaves to assume the master role over the affected network

device(s).

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Failback (step 2)

When the configured master recovers from a failure and rejoins the team, or when the connection from the

disconnected device(s) with the original master is resumed, ROS initiates a failback operation in which the

master role is restored to the configured master as defined in the region definition.

Reference: HP VAN SDN Controller Administrator Guide