Abstract: A configuration system for configuring the control-plane of a software-defined network is presented. The configuration system determines an entity-specific group of control-plane functionalities for each of controller entities located in a distributed way in the software-defined network. The control-plane functionalities are suitable for configuring data forwarding network elements, such as routers, to support services to be provided by the software-defined network. The configuration system composes, on the basis of the entity-specific groups, entity-specific portions of control data and transmits the entity-specific portions of the control data to the controller entities so as to configure each controller entity to support the corresponding entity-specific group of the control-plane functionalities.

Abstract: A configuration system for configuring the control-plane of a software-defined network is presented. The configuration system determines an entity-specific group of control-plane functionalities for each of controller entities located in a distributed way in the software-defined network. The control-plane functionalities are suitable for configuring data forwarding network elements, such as routers, to support services to be provided by the software-defined network. The configuration system composes, on the basis of the entity-specific groups, entity-specific portions of control data and transmits the entity-specific portions of the control data to the controller entities so as to configure each controller entity to support the corresponding entity-specific group of the control-plane functionalities.

Abstract: A network element (101-104) of a software-defined network is adapted to construct a configuration system on the basis of configuration data received from a controller (105, 106) of the software-defined network. The network element is arranged to transmit, in response to an event indicating a need to verify the configuration system, status information to the controller. The event may include for example a loss and a subsequent reestablishment of a connection between the network element and the controller. The status information indicates a first portion of the configuration data which has been implemented in the configuration system prior to the event. After receiving the status information, the controller is able transmit an appropriate second portion of the configuration data to the network element so as to enable verification of an appropriate portion of the configuration system. Thus, there is no need to verify the whole configuration system after the event.

Abstract: A network element (101-104) of a software-defined network is adapted to construct a configuration system on the basis of configuration data received from a controller (105, 106) of the software-defined network. The network element is arranged to transmit, in response to an event indicating a need to verify the configuration system, status information to the controller. The event may include for example a loss and a subsequent re-establishment of a connection between the network element and the controller. The status information indicates a first portion of the configuration data which has been implemented in the configuration system prior to the event. After receiving the status information, the controller is able transmit an appropriate second portion of the configuration data to the network element so as to enable verification of an appropriate portion of the configuration system. Thus, there is no need to verify the whole configuration system after the event.

Abstract: The invention relates to determining mutual differences of transmission delays experienced by protocol data units transmitted in a communications network. This invention is based on a surprising discovery that the time difference between the receiving moments of protocol data units the temporal receiving order of which deviates from their temporal transmitting order represents the smallest possible difference between the transmission delays experienced by these protocol data units. In a method according to the invention it is determined, based on an order indicator associated with a protocol data unit received at an earlier point of time and an order indicator associated with a protocol data unit received at a later point of time, whether the mutual order of the protocol data units changed during transmission.

Abstract: Determining mutual differences of transmission delays experienced by protocol data units transmitted in a communications network is based on a surprising discovery that the time difference between the receiving moments of protocol data units the temporal receiving order of which deviates from their temporal transmitting order represents the smallest possible difference between the transmission delays experienced by these protocol data units. In a method it is determined, based on an order indicator associated with a protocol data unit received at an earlier point of time and an order indicator associated with a protocol data unit received later, whether the mutual order of the protocol data units changed during transmission. If the mutual order has changed, the time difference between the receiving moments of the protocol data units is calculated, which time difference represents the smallest possible difference between the transmission delays experienced by these protocol data units.

Abstract: The invention relates to determining mutual differences of transmission delays experienced by protocol data units transmitted in a communications network. This invention is based on a surprising discovery that the time difference between the receiving moments of protocol data units the temporal receiving order of which deviates from their temporal transmitting order represents the smallest possible difference between the transmission delays experienced by these protocol data units. In a method according to the invention it is determined, based on an order indicator associated with a protocol data unit received at an earlier point of time and an order indicator associated with a protocol data unit received at a later point of time, whether the mutual order of the protocol data units changed during transmission.

Abstract: Determining mutual differences of transmission delays experienced by protocol data units transmitted in a communications network is based on a surprising discovery that the time difference between the receiving moments of protocol data units the temporal receiving order of which deviates from their temporal transmitting order represents the smallest possible difference between the transmission delays experienced by these protocol data units. In a method it is determined, based on an order indicator associated with a protocol data unit received at an earlier point of time and an order indicator associated with a protocol data unit received later, whether the mutual order of the protocol data units changed during transmission. If the mutual order has changed, the time difference between the receiving moments of the protocol data units is calculated, which time difference represents the smallest possible difference between the transmission delays experienced by these protocol data units.