NS-3 based Named Data Networking (NDN) simulator
ndnSIM 2.5: NDN, CCN, CCNx, content centric networks
API Documentation
nfd::fw::AccessStrategy Class Reference

Access Router Strategy version 1. More...

#include <access-strategy.hpp>

Inheritance diagram for nfd::fw::AccessStrategy:
Collaboration diagram for nfd::fw::AccessStrategy:

Public Member Functions

 AccessStrategy (Forwarder &forwarder, const Name &name=getStrategyName())
 
void afterReceiveInterest (const Face &inFace, const Interest &interest, const shared_ptr< pit::Entry > &pitEntry) override
 trigger after Interest is received More...
 
void beforeSatisfyInterest (const shared_ptr< pit::Entry > &pitEntry, const Face &inFace, const Data &data) override
 trigger before PIT entry is satisfied More...
 
- Public Member Functions inherited from nfd::fw::Strategy
 Strategy (Forwarder &forwarder)
 construct a strategy instance More...
 
virtual ~Strategy ()
 
const NamegetInstanceName () const
 
virtual void afterContentStoreHit (const shared_ptr< pit::Entry > &pitEntry, const Face &inFace, const Data &data)
 trigger after a Data is matched in CS More...
 
virtual void afterReceiveData (const shared_ptr< pit::Entry > &pitEntry, const Face &inFace, const Data &data)
 trigger after Data is received More...
 
virtual void afterReceiveNack (const Face &inFace, const lp::Nack &nack, const shared_ptr< pit::Entry > &pitEntry)
 trigger after Nack is received More...
 
virtual void onDroppedInterest (const Face &outFace, const Interest &interest)
 trigger after Interest dropped for exceeding allowed retransmissions More...
 

Static Public Member Functions

static const NamegetStrategyName ()
 
- Static Public Member Functions inherited from nfd::fw::Strategy
template<typename S >
static void registerType (const Name &strategyName=S::getStrategyName())
 register a strategy type More...
 
static bool canCreate (const Name &instanceName)
 
static unique_ptr< Strategycreate (const Name &instanceName, Forwarder &forwarder)
 
static bool areSameType (const Name &instanceNameA, const Name &instanceNameB)
 
static std::set< NamelistRegistered ()
 
static const NamegetStrategyName ()
 

Additional Inherited Members

- Protected Member Functions inherited from nfd::fw::Strategy
void sendInterest (const shared_ptr< pit::Entry > &pitEntry, Face &outFace, const Interest &interest)
 send Interest to outFace More...
 
void sendData (const shared_ptr< pit::Entry > &pitEntry, const Data &data, const Face &outFace)
 send data to outFace More...
 
void sendDataToAll (const shared_ptr< pit::Entry > &pitEntry, const Face &inFace, const Data &data)
 send data to all matched and qualified faces More...
 
void rejectPendingInterest (const shared_ptr< pit::Entry > &pitEntry)
 schedule the PIT entry for immediate deletion More...
 
void sendNack (const shared_ptr< pit::Entry > &pitEntry, const Face &outFace, const lp::NackHeader &header)
 send Nack to outFace More...
 
void sendNacks (const shared_ptr< pit::Entry > &pitEntry, const lp::NackHeader &header, std::initializer_list< const Face * > exceptFaces=std::initializer_list< const Face * >())
 send Nack to every face that has an in-record, except those in exceptFaces More...
 
void setExpiryTimer (const shared_ptr< pit::Entry > &pitEntry, time::milliseconds duration)
 Schedule the PIT entry to be erased after duration. More...
 
const fib::EntrylookupFib (const pit::Entry &pitEntry) const
 performs a FIB lookup, considering Link object if present More...
 
MeasurementsAccessorgetMeasurements ()
 
FacegetFace (FaceId id) const
 
const FaceTablegetFaceTable () const
 
void setInstanceName (const Name &name)
 set strategy instance name More...
 
- Static Protected Member Functions inherited from nfd::fw::Strategy
static ParsedInstanceName parseInstanceName (const Name &input)
 parse a strategy instance name More...
 
static Name makeInstanceName (const Name &input, const Name &strategyName)
 construct a strategy instance name More...
 
- Protected Attributes inherited from nfd::fw::Strategy
signal::Signal< FaceTable, Face & > & afterAddFace
 
signal::Signal< FaceTable, Face & > & beforeRemoveFace
 

Detailed Description

Access Router Strategy version 1.

This strategy is designed for the last hop on the NDN testbed, where each nexthop connects to a laptop, links are lossy, and FIB is mostly correct.

  1. Multicast the first Interest to all nexthops.
  2. When Data comes back, remember last working nexthop of the prefix; the granularity of this knowledge is the parent of Data Name.
  3. Forward subsequent Interests to the last working nexthop. If it doesn't respond, multicast again.

Definition at line 49 of file access-strategy.hpp.

Constructor & Destructor Documentation

◆ AccessStrategy()

Member Function Documentation

◆ getStrategyName()

const Name & nfd::fw::AccessStrategy::getStrategyName ( )
static

Definition at line 53 of file access-strategy.cpp.

Referenced by AccessStrategy().

◆ afterReceiveInterest()

void nfd::fw::AccessStrategy::afterReceiveInterest ( const Face inFace,
const Interest interest,
const shared_ptr< pit::Entry > &  pitEntry 
)
overridevirtual

trigger after Interest is received

The Interest:

  • does not violate Scope
  • is not looped
  • cannot be satisfied by ContentStore
  • is under a namespace managed by this strategy

The PIT entry is set to expire after InterestLifetime has elapsed at each downstream.

The strategy should decide whether and where to forward this Interest.

  • If the strategy decides to forward this Interest, invoke sendInterest for each upstream, either now or shortly after via a scheduler event, but before PIT entry expires. Optionally, the strategy can invoke setExpiryTimer to adjust how long it would wait for a response.
  • If the strategy has already forwarded this Interest previously and decides to continue waiting, do nothing. Optionally, the strategy can invoke setExpiryTimer to adjust how long it would wait for a response.
  • If the strategy concludes that this Interest cannot be satisfied, invoke rejectPendingInterest to erase the PIT entry.
Warning
The strategy must not retain shared_ptr<pit::Entry>, otherwise undefined behavior may occur. However, the strategy is allowed to store weak_ptr<pit::Entry>.

Implements nfd::fw::Strategy.

Definition at line 60 of file access-strategy.cpp.

References nfd::fw::RetxSuppressionFixed::decidePerPitEntry(), nfd::fw::FORWARD, nfd::face::Face::getId(), nfd::fw::NEW, NFD_LOG_DEBUG, and nfd::fw::SUPPRESS.

◆ beforeSatisfyInterest()

void nfd::fw::AccessStrategy::beforeSatisfyInterest ( const shared_ptr< pit::Entry > &  pitEntry,
const Face inFace,
const Data data 
)
overridevirtual

trigger before PIT entry is satisfied

This trigger is invoked when an incoming Data satisfies more than one PIT entry. The strategy can collect measurements information, but cannot manipulate Data forwarding. When an incoming Data satisfies only one PIT entry, afterReceiveData is invoked instead and given full control over Data forwarding. If a strategy does not override afterReceiveData, the default implementation invokes beforeSatisfyInterest.

Normally, PIT entries would be erased after receiving the first matching Data. If the strategy wishes to collect responses from additional upstream nodes, it should invoke setExpiryTimer within this function to prolong the PIT entry lifetime. If a Data arrives from another upstream during the extended PIT entry lifetime, this trigger will be invoked again. At that time, this function must invoke setExpiryTimer again to continue collecting more responses.

In this base class this method does nothing.

Warning
The strategy must not retain shared_ptr<pit::Entry>, otherwise undefined behavior may occur. However, the strategy is allowed to store weak_ptr<pit::Entry>.

Reimplemented from nfd::fw::Strategy.

Definition at line 216 of file access-strategy.cpp.

References nfd::face::Face::getId(), NFD_LOG_DEBUG, and ndn::time::steady_clock::now().


The documentation for this class was generated from the following files: