Network use has evolved to be dominated by content distribution and retrieval, while networking technology is mainly concerned with connections between named hosts. Accessing content and services requires the mapping of what users care about to where the content is located. Content Centric Networking (CCN) is a new paradigm in networking and a future Internet architecture that treats content as the primitive, decoupling location from identity, security, and access to retrieve content by name. The figure below shows the operation of the Request-Response communication pattern of CCN and the node architecture of a CCN node with the the different functional elements and the 3-layer protocol architecture.

inbaverSim is an OMNeT++ based model framework to simulate CCN-based networks. The functionality and the message formats follow the description provided in RFC 8569 and RFC 8609. An overview of the model framework is provided in the publication inbaverSim: An OMNeT++ Model Framework for Content Centric Networking.

The sections that follow provide details of inbaverSim, including installation, node architecture, and more. The text immediately below is a TL;DR summary of how to install and run simulations with inbaverSim.

1. Install the latest version of OMNeT++
2. Run the OMNeT++ IDE and install the INET model framework
3. Build the INET model framework in mode
4. Import inbaverSim repository (this repository) by cloning from GitHub inbaverSim
5. Build inbaverSim project
6. Run simulations using the 'omnetpp-simple-network.ini'

Node Models

inbaverSim can model the operation of different types of CCN nodes and networks. A list of node types is given below.

• Wireless Nodes - Nodes that can connect to infrastructure-based wireless networks (e.g., WLAN, LTE)
• Wireless Access Routers - Routers that are access points/base stations for wireless nodes
• DTN/OppNets Nodes - Wireless nodes that employ direct communications between nodes
• Wired Nodes - Nodes connected to networks over wired network attachments
• Access Routers - Routers for wired network nodes
• Core Routers - Central CCN routers that connect other networks
• Content Servers - Servers that host content
• Wireless Sensor Nodes - Wireless sensor nodes deployed with sensors (temperature, humidity, etc.)
• Wireless Actuator Nodes - Wireless actuator nodes deployed with sensors to actuate devices
• IOT Gateways - Gateways connecting wireless sensor networks and the Internet
• Internet - Node simulating a CCN-based Internet where the behaviour of many nodes and applications is simulated

The picture below shows the topology of a CCN network with all the above nodes.

Protocol Stack

The node architecture of an inbaverSim node of any type consists of a 3-layer protocol stack as seen from the following picture.

• Application: All CCN-based applications are deployed at this layer
• Forwarding: The forwarding mechanism described in RFC 8569 or another custom CCN forwarding mechanism is implemented at this layer (e.g., DTN, IoT)
• Transport: This layer implements different transports that connect nodes to deliver CCN packets. Currently, two types of transports are supported: conceptual wired and wireless transports.

The picture below shows the inbaverSim node model architecture in OMNeT++.

Installing

inbaverSim is written for OMNeT++ and additionally uses the INET model framework of OMNeT++. Therefore, they have to be installed first to use inbaverSim. The installation procedure is as follows.

1. Install OMNeT++ - OMNeT provides an Install Guilde to install OMNeT++ on different operating systems.

2. Install INET Model Framework - Installing is done through the OMNeT++ IDE. The steps are as follows.

• Run the OMNeT++ IDE
• Create a new workspace
• After creating the workspace, the IDE will prompt asking to install INET
• Once the INET code base is installed, rebuild INET in 'release' mode

3. Install inbaverSim and build as follows.

• Import the code from the GitHub repository
• Adjust project properties ('Project References' and 'C/C++ General->Paths and Symbols')
• Build inbaverSim

If there are problems when building the model, check FAQ

Running Simulations

The 'simulation' folder contains sample '.ini' files for running simulations. The procedure for running a simulation is given below.

1. Set up the '.ini' file to run simulations as follows.

• Select a sample '.ini' file from the 'simulations' folder
• Open the file by double-clicking
• Add/adjust parameters as required (e.g., change 'sim-time-limit' to a different duration)

2. Simulate as follows.

• Select '.ini' file
• Right-click and click on 'Run As'->'OMNeT++ Simulation'
• Select the 'Config name' in the new window that will pop up
• Select the 'Run' button to run the simulation

The pictures below show two different CCN networks created to simulate. The first picture shows a simple CCN network that includes wireless and wired nodes connected to a network with CCN infrastructure (routers and content servers)

The second network is an IoT network comprising various CCN node types, including a CCN-based sensor network and the Internet node type.

Statistics

Every simulation generates statistics during its run. These statistics are collected in the 'simulations/results' folder. Use the results extraction and viewing capability of the OMNeT++ IDE to view the results, or export the results in CSV/JSON formats to use external plotting tools.

The figure below compares the content hit ratio for two CCN networks with different content catalog sizes. The simulations are run for 48 hours.

The figure below shows the flow ratio (ratio between Interests and Content Objects). Reflexive Forwarding (RF) is used to handle the unique communication patterns in the Internet of Things (IoT). This results in more pending Interests existing in the network compared to traditional CCN communications.

Questions and Comments

If you have any questions or comments about inbaverSim, write to us at inbaverSim@comnets.uni-bremen.de