To simulate the Content-Centric Networking (CCN) projects using OMNeT++ that encompasses modeling a network in which the main focus is on content instead of the host or device providing it. CCN, a part of Named Data Networking (NDN), routes and forwards data according to the content names rather than IP addresses. This network architecture supports effective content distribution, caching, and minimizing network congestion.
Below is a step-by-step instruction to mimic Content-Centric Networking (CCN) projects using OMNeT++:
Steps to Simulate Content Centric Network Projects in OMNeT++
- Install OMNeT++ and Required Frameworks
- OMNeT++: Download and install OMNeT++ from omnetpp.org.
- INET Framework: We can download and install the INET Framework from inet.omnetpp.org. INET framework supports numerous networking protocols and can be expanded for CCN functionalities.
- CCN Extensions: We may require to prolong INET or improve custom modules to replicate CCN functionality like content naming, Interest packet forwarding, and content caching.
- Understand CCN Components
In a CCN network, the below components are critical:
- Content Name: Data is detected by its name, not the position (IP address) in which it resides.
- Interest Packets: Requirements for content transmitted by users or nodes. These packets are carry content names and traverse the network to discover the content.
- Data Packets: Content returned in response to Interest packets.
- Pending Interest Table (PIT): A table conserved by routers to track outstanding Interest packets awaiting responses.
- Content Store (CS): A cache utilized by routers to store recently fetched content to satisfy upcoming requests locally.
- Forwarding Information Base (FIB): A table, which supports routers forward Interest packets according to the content name.
- Set Up a Basic CCN Topology in NED
In the NED file, we describe a single CCN topology, which contains producers, consumers, and CCN routers. These components are communicate by exchanging Interest and Data packets.
Example NED file for a simple CCN setup:
network CCNNetwork
{
submodules:
consumerNode: CCNConsumer;
producerNode: CCNProducer;
router1: CCNRouter;
router2: CCNRouter;
connections:
consumerNode.ethg++ <–> EthLink <–> router1.ethg++;
router1.ethg++ <–> EthLink <–> router2.ethg++;
router2.ethg++ <–> EthLink <–> producerNode.ethg++;
}
- CCNConsumer: Denotes a node, which generates Interest packets to request content.
- CCNProducer: Signifies a node that stores and serves content.
- CCNRouter: Executes CCN functionality such as forwarding Interest packets, conserving PIT, caching data, and serving content from the cache.
- Configure the Network in the INI File
The .ini file describes the metrics for content requests, packet forwarding, and caching policies. We can set up each node and router to manage the CCN traffic.
Example INI configuration:
[General]
network = CCNNetwork
sim-time-limit = 500s
# Consumer settings (generates Interest packets)
*.consumerNode.numApps = 1
*.consumerNode.app[0].typename = “CCNConsumerApp”
*.consumerNode.app[0].contentName = “/video/chunk1”
*.consumerNode.app[0].requestInterval = 2s
# Producer settings (provides Data packets)
*.producerNode.numApps = 1
*.producerNode.app[0].typename = “CCNProducerApp”
*.producerNode.app[0].contentName = “/video/chunk1”
# CCN Router cache settings
*.router1.cacheSize = 100MB
*.router2.cacheSize = 100MB
*.router1.cacheReplacementPolicy = “LRU” # Least Recently Used (LRU) cache policy
*.router2.cacheReplacementPolicy = “FIFO” # First-In-First-Out (FIFO) cache policy
- CCNConsumerApp: Mimics a consumer, which generates Interest packets for content.
- CCNProducerApp: Replicates a producer that works content in response to Interest packets.
- cacheSize: Identifies the cache size in each router for content storage.
- cacheReplacementPolicy: Describes the cache replacement policy (e.g., LRU, FIFO) when the cache is full.
- Implement Interest Packet Forwarding
Routers forward Interest packets rely on the content names. If the content is discovered in the cache then the router transmits the Data packet immediately. If not, the Interest packet is sent toward the producer.
Example pseudocode for Interest forwarding in a CCN router:
void CCNRouter::forwardInterest(cMessage *interest) {
string contentName = extractContentName(interest);
if (contentStore.contains(contentName)) {
// Respond with cached data
cMessage *dataPacket = contentStore.get(contentName);
send(dataPacket, “out”);
} else {
// Check the Pending Interest Table (PIT) to avoid sending duplicate requests
if (!pit.contains(contentName)) {
pit.insert(interest);
forwardToNextHop(interest);
}
}
}
void CCNRouter::handleDataPacket(cMessage *data) {
string contentName = extractContentName(data);
// Cache the received data for future requests
contentStore.insert(contentName, data);
// Send data to all requesters in the PIT
list<string> requesters = pit.getRequesters(contentName);
for (auto requester : requesters) {
send(data, requester);
}
// Remove the entry from the PIT
pit.remove(contentName);
}
- forwardInterest(): Forwards Interest packets if the content is not in the cache, or else serves cached content if obtainable.
- handleDataPacket(): Manages incoming Data packets, caches them, and forwards them to the requesters.
- Simulate Content Caching and Replacement
Each CCN Router can cache content. We can replicate distinct cache replacement policies, like LRU or FIFO, to learn their effect on cache hit rates and network performance.
Example of handling cache replacement:
void CCNRouter::cacheData(cMessage *data) {
string contentName = extractContentName(data);
if (contentStore.isFull()) {
// Apply cache replacement policy (e.g., LRU)
contentStore.evict();
}
// Insert new content into the cache
contentStore.insert(contentName, data);
}
- cacheData(): Handles the insertion of content into the cache and applies the replacement policy when the cache is full.
- Simulate Traffic Flows and Network Performance
We can mimic numerous traffic patterns by adapting the content request interval for consumers and monitoring how routers manage the requests. It contains estimating performance metrics such as:
- Cache Hit Ratio: The percentage of content requests functioned from the cache.
- Latency: The delay in serving content to consumers.
- Throughput: The amount of content are delivered to consumers over time.
- Interest Satisfaction Rate: The percentage of Interest packets, which are satisfied with Data packets.
- Run the Simulation
- Build the project: We can compile the project by choosing Project > Build All within OMNeT++.
- Run the simulation: We can utilize Run Configurations within OMNeT++ to execute the simulation. We can be used Qtenv to envision how Interest and Data packets flow via the network, in addition to how content is cached and recovered.
- Analyze Simulation Results
OMNeT++ creates the scalar and vector outcome files, which offer insights into network performance. Significant performance parameters in CCN projects contain:
- Cache Hit Ratio: Percentage of Interest packets are served from router caches.
- Latency: Time taken to serve content requests as of the network.
- Packet Loss: Amount of lost Interest or Data packets because of the network congestion or resource limitations.
- Data Delivery Time: The time from transmitting an Interest to receiving the corresponding Data packet.
We can utilise the Plove or export the outcomes to external tools like MATLAB or Python for more detailed analysis.
- Advanced CCN Scenarios
We can expand the CCN simulation by inserting furthered aspects:
- Caching Strategies: Replicate distinct caching strategies such as probabilistic caching or adaptive caching to enhance the network performance.
- Multi-path Forwarding: Mimic scenarios in which routers forward Interest packets along numerous paths to enhance the content retrieval reliability.
- Security in CCN: Replicate content authentication, privacy protection, and content verification mechanisms in CCN to learn the security challenges.
- CCN in Mobile Networks: Prolong the simulation to mobile networks in which consumer and producer nodes are move dynamically, influencing the content availability and forwarding strategies.
Example CCN Project Ideas:
- Impact of Cache Replacement Policies on CCN Performance: Mimic and compare distinct cache replacement policies (e.g., LRU, FIFO, and Random) and then examine its influence on cache hit ratio, latency, and network throughput.
- Optimizing Cache Placement in CCN: Analyse optimal cache placement strategies in the network to reduce the latency and increase cache hit ratios.
- Multi-path Forwarding in CCN: Replicate multi-path Interest forwarding and examine its effect on content retrieval reliability and network performance.
- Energy-Efficient CCN: Learn energy-efficient forwarding and caching mechanisms within CCN to reduce the energy consumption of routers and nodes.
In this outline, Content Centric Network was delivered through the systematic approaches, replicated and analysed with the help of the simulation tool OMNeT++. More information and details on this subject will be presented, if required.
Keep connected with phdprime.com for more research ideas and topics. We offer comprehensive support with in-depth simulation guidance on Content Centric Network Projects using the OMNeT++ tool, complete with detailed explanations.