Package org.onosproject.net.intent

Set of abstractions for conveying high-level intents for treatment of selected network traffic by allowing applications to express the what rather than the how.

See: Description

Interface Summary

Interface	Description
Constraint	Representation of a connectivity constraint capable of evaluating a link and determining the cost of traversing that link in the context of this constraint.
IntentBatchDelegate	Facade for receiving notifications from the intent batch service.
IntentBatchListener	Listener for intent events.
IntentBatchService	Service for tracking and delegating batches of intent operations.
IntentCompiler<T extends Intent>	Abstraction of a compiler which is capable of taking an intent and translating it to other, potentially installable, intents.
IntentExtensionService	Service for extending the capability of intent framework by adding additional compilers or/and installers.
IntentInstaller<T extends Intent>	Abstraction of entity capable of installing intents to the environment.
IntentListener	Listener for intent events.
IntentService	Service for application submitting or withdrawing their intents.
IntentStore	Manages inventory of end-station intents; not intended for direct use.
IntentStoreDelegate	Intent store delegate abstraction.

Class Summary

Class	Description
BatchWrite
BatchWrite.Operation
ConnectivityIntent	Abstraction of connectivity intent for traffic matching some criteria.
HostToHostIntent	Abstraction of end-station to end-station bidirectional connectivity.
Intent	Abstraction of an application level intent.
IntentBatchLeaderEvent	A class to represent an intent related event.
IntentEvent	A class to represent an intent related event.
IntentId	Intent identifier suitable as an external key.
IntentOperation	Abstraction of an intent-related operation, e.g.
IntentOperations	Batch of intent submit/withdraw/replace operations.
IntentOperations.Builder	Builder for batches of intent operations.
LinkCollectionIntent	Abstraction of a connectivity intent that is implemented by a set of path segments.
MultiPointToSinglePointIntent	Abstraction of multiple source to single destination connectivity intent.
OpticalConnectivityIntent	An optical layer intent for connectivity from one transponder port to another transponder port.
OpticalPathIntent
PathIntent	Abstraction of explicitly path specified connectivity intent.
PointToPointIntent	Abstraction of point-to-point connectivity.
SinglePointToMultiPointIntent	Abstraction of single source, multiple destination connectivity intent.

Enum Summary

Enum	Description
BatchWrite.OpType
IntentBatchLeaderEvent.Type
IntentEvent.Type
IntentOperation.Type	Operation type.
IntentState	Representation of the phases an intent may attain during its lifecycle.

Exception Summary

Exception	Description
IntentException	Represents an intent related error.

Package org.onosproject.net.intent Description

Set of abstractions for conveying high-level intents for treatment of selected network traffic by allowing applications to express the what rather than the how. This makes such instructions largely independent of topology and device specifics, thus allowing them to survive topology mutations.

The controller core provides a suite of built-in intents and their compilers and installers. However, the intent framework is extensible in that it allows additional intents and their compilers or installers to be added dynamically at run-time. This allows others to enhance the initial arsenal of connectivity and policy-based intents available in base controller software.

The following diagram depicts the state transition diagram for each top-level intent:

The controller core accepts the intent specifications and translates them, via a process referred to as intent compilation, to installable intents, which are essentially actionable operations on the network environment. These actions are carried out by intent installation process, which results in some changes to the environment, e.g. tunnel links being provisioned, flow rules being installed on the data-plane, optical lambdas being reserved.

After an intent is submitted by an application, it will be sent immediately (but asynchronously) into a compiling phase, then to installing phase and if all goes according to plan into installed state. Once an application decides it no longer wishes the intent to hold, it can withdraw it. This describes the nominal flow. However, it may happen that some issue is encountered. For example, an application may ask for an objective that is not currently achievable, e.g. connectivity across to unconnected network segments. If this is the case, the compiling phase may fail to produce a set of installable intents and instead result in a failed compile. If this occurs, only a change in the environment can trigger a transition back to the compiling state.

Similarly, an issue may be encountered during the installation phase in which case the framework will attempt to recompile the intent to see if an alternate approach is available. If so, the intent will be sent back to installing phase. Otherwise, it will be parked in the failed state. Another scenario that’s very likely to be encountered is where the intent is successfully compiled and installed, but due to some topology event, such as a downed or downgraded link, loss of throughput may occur or connectivity may be lost altogether, thus impacting the viability of a previously satisfied intent. If this occurs, the framework will attempt to recompile the intent, and if an alternate approach is available, its installation will be attempted. Otherwise, the original top-level intent will be parked in the failed state.

Please note that all *ing states, depicted in orange, are transitional and are expected to last only a brief amount of time. The rest of the states are parking states where the intent may spent some time; except for the submitted state of course. There, the intent may pause, but only briefly, while the system determines where to perform the compilation or while it performs global recomputation/optimization across all prior intents.