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Strategy Choice Management

Strategy Choice Management is a module of NFD Management protocol.
It provides:

  • commands to choose the forwarding strategy for a namespace
  • a dataset of strategy choices

Strategy Choice Management commands and datasets are available under namespace ndn:/localhost/nfd/strategy-choice.

Strategy

A strategy is identified by a name.

NFD currently supports the following strategies:

  • ndn:/localhost/nfd/strategy/best-route
  • ndn:/localhost/nfd/strategy/broadcast
  • ndn:/localhost/nfd/strategy/client-control
  • ndn:/localhost/nfd/strategy/ncc
  • ndn:/localhost/nfd/strategy/access
  • ndn:/localhost/nfd/strategy/asf

Each strategy listed above may have one or more versions. Strategy version is increased when there is a major behavior change; bugfixes usually won't bump strategy version. The version component is appended to the strategy name.
A strategy may accept parameters name components. Parameters are always optional. They may be appended to the strategy name after the version component. Whether a strategy accepts parameters and the syntax and semantics of the parameters are defined by each strategy.

Control Commands

ControlCommand management-module: strategy-choice

Set the strategy for a namespace

command-verb: set

ControlParameters fields:

  • Name (required)
  • Strategy (required)

Name is the Name prefix on which the strategy is selected.

Strategy must be a Name that identifies a strategy.

It could be either an unversioned name to instantiate the latest version of a strategy, or a versioned name to instantiate a specific version. If the chosen strategy accepts parameters, they may be appended after a versioned name.
If Strategy does not match any registered strategy, the command fails with code 404.

If the command succeeds, <Body> in ControlResponse block contains updated ControlParameters:

  • Name: unchanged
  • Strategy: strategy instance name, which always contains a version component and may contain parameters name components

Unset the strategy for a namespace

command-verb: unset

ControlParameters fields:

  • Name (required)

After this operation, the effective strategy at Name is inherited from the parent.

If there is no strategy defined at Name, this command does nothing, but is still considered successful.

Name must not be ndn:/, otherwise the command fails with code 400.

Strategy Choice Dataset

Strategy choices for namespaces are published as a Status Dataset at ndn:/localhost/nfd/strategy-choice/list.

Each choice is represented by a StrategyChoice block:

StrategyChoice := STRATEGY-CHOICE-TYPE TLV-LENGTH
                    Name
                    Strategy
  • Name is the namespace on which a strategy is chosen.
  • Strategy is the strategy chosen for this namespace.

TLV-TYPE assignments

Type Assigned value Assigned value (hex)
StrategyChoice 128 0x80