ndn-cxx Application Developer Guide

This document describes ndn-cxx: NDN C++ library with eXperimental eXtensions, and how to develop an NDN application using the ndn-cxx library.

Introduction

• history of ndn-cxx, comparison with ndn-ccl-api
• what should be included in ndn-cxx
• what should not be included in ndn-cxx

Application Design

This section describes how to design an application that can work well with NDN architecture and ndn-cxx library.

Data Naming

• fundamental difference between NDN content distribution model and IP communication model
• same content should have same Name
• Data is immutable: version component
• segmenting

Interests

• how Interest matches Data
• discover names with Interest Selectors, then retrieve with predictable names
• avoid abusing Selectors

Security

• Data carries signature
• signed Interest for command
• communication channel is not secured: secrets should be protected by encryption (not signed Interest)
• trust management: identity, public key, certificate (more details in Security section)

Application Implementation

This section describes how to implement an application with ndn-cxx library.

Basics

• start a project: obtain build flags with pkg-config, include ndn-cxx headers, C++ namespace consideration
• Name, Interest, Data classes
• Face class, asynchronous operation, event loop

Producer

• prefix registration and Interest filter
• in-app storage and its difference from ContentStore

Consumer

• Interest pipeling for segmented dataset
• retransmissions

Security

• signing with KeyChain
• verification with ValidatorConfig (more details in Security section)

Integration with Other Components

• Boost.Asio event loop
• scheduler

Interacting with NFD Management

• nfd::Controller class and control commands
• status dataset
• notification stream
• local control header

Security

This section explains more about security features.

Concepts

• identity, public key, certificate
• TPM
• PIB and PIB service
• KeyChain
• Validator

Credential Management

• select PIB and TPM with client.conf
• ndnsec commands
• publish certificates using PIB service

Trust Model

• hierarchical trust model, and how to validate with ValidatorConfig
• web-of-trust trust model, and how to validate with ValidatorConfig
• considerations on designing a custom trust model

Library Internals

This section describes internals of the ndn-cxx library, useful for those who want to extend the library.

TLV encoding

• constants in ndn::tlv namespace
• Block and Buffer
• EncodingBuffer and EncodingEstimator
• how to implement a TLV abstraction type

Transport

• interface between Face and Transport
• select transport with Face constructor
• select transport with client.conf
• how to implement a transport