To simulate Wide Area Networks (WANs) in OMNeT++ has includes to setting up a large-scale network with multiple subnets, routers, and long-distance communication links. Wide Area Networks usually span via cities, regions, or even countries and it contain complex routing, data transmission, and bandwidth management.
Here is a detailed guide on how to simulate WAN projects using OMNeT++:
Steps to Simulate Wide Area Networks Projects in OMNeT++
- Install OMNeT++
- First, download and install OMNeT++.
- Ensure the installation is successful by processing example simulations included with OMNeT++.
- Install and Set Up the INET Framework
- To replicate WANs, we want to install the INET framework that contain numerous network components such as routers, switches, hosts, and protocols necessary for WAN simulations.
- We can download the latest INET framework from INET GitHub repository and install it based on the provided instructions.
- Understand WAN Characteristics
- Wide Area Networks (WANs) usually includes multiple local area networks (LANs) connected through routers, with large geographical distances separating them. Communication happens over high-latency links, has contained fiber optics, satellite, or leased lines.
- WANs also utilize routing protocols such as OSPF, BGP, RIP, and MPLS to route data over long distances.
- Designing a WAN Network Topology
- In a usual WAN, we will have multiple subnets (LANs) interconnected through routers, with hosts (servers, clients) within each subnet.
- Utilize OMNeT++’s NED (Network Description) language to describe the topology with routers, switches, hosts, and links signify different geographical locations.
Example of a basic WAN topology in a NED file:
network WANExample {
submodules:
routerA: Router {
@display(“p=100,100;i=router”);
}
routerB: Router {
@display(“p=400,100;i=router”);
}
routerC: Router {
@display(“p=250,300;i=router”);
}
lanA: LAN {
@display(“p=50,250”);
}
lanB: LAN {
@display(“p=450,250”);
}
connections:
routerA.pppg++ <–> PointToPointLink <–> routerB.pppg++;
routerA.pppg++ <–> PointToPointLink <–> routerC.pppg++;
routerB.pppg++ <–> PointToPointLink <–> routerC.pppg++;
lanA.switch.pppg++ <–> EthernetLink <–> routerA.pppg++;
lanB.switch.pppg++ <–> EthernetLink <–> routerB.pppg++;
}
This generates a simple WAN with three routers (routerA, routerB, and routerC) associated by point-to-point links, each connected to a local area network (lanA and lanB).
- Configure Links for Wide Area Networks
WAN links usually have high latency and lower bandwidth reated to LANs. We can setup these parameters in the NED file or in the .ini configuration file.
Example configuration for WAN links:
channel PointToPointLink extends DatarateChannel {
datarate = 100Mbps;
delay = 50ms; // 50ms delay to simulate long-distance link
ber = 1e-7; // Bit error rate to simulate possible packet loss
}
This simulates a WAN link with a 100 Mbps data rate, 50 ms latency, and bit error rate of 1e-7.
- Configure Routing Protocols
For WANs, routing protocols such as OSPF (Open Shortest Path First), BGP (Border Gateway Protocol), or RIP (Routing Information Protocol) are commonly used.
- OSPF is an intra-domain protocol for identifying the shortest path among routers within an autonomous system.
- BGP is utilized for inter-domain routing, like communication among different ISPs.
Example of enabling OSPF routing:
**.router[*].routingTable.typename = “OspfRouting”
**.router[*].ospfConfigFile = xmldoc(“ospfConfig.xml”)
RIP configuration can be similarly done:
**.router[*].routingTable.typename = “RipRouting”
**.router[*].interfaceTable.typename = “InterfaceTable”
- Configure Traffic Generation
To replicate WAN traffic, we can utilize numerous application layer protocols like TCP, UDP, or replicate specific network services such as HTTP, FTP, or video streaming.
Example configuration for generating UDP traffic:
**.lanA.host[0].app[0].typename = “UdpBasicApp”
**.lanA.host[0].app[0].destAddr = “lanB.host[0]”
**.lanA.host[0].app[0].messageLength = 1024B
**.lanA.host[0].app[0].sendInterval = exponential(1s)
This generates a UDP traffic generator on lanA.host[0] that sends 1024-byte packets to lanB.host[0] at random intervals (exponentially distributed).
- Set up Simulation Parameters
Set up numerous contexts of the simulation, like simulation time, link characteristics, and application settings in the .ini file.
Example .ini configuration:
network = WANExample
sim-time-limit = 200s
# WAN link settings
**.routerA.pppg++ <–> routerB.pppg++.datarate = 100Mbps
**.routerA.pppg++ <–> routerB.pppg++.delay = 50ms
# OSPF routing protocol
**.router[*].routingTable.typename = “OspfRouting”
**.router[*].ospfConfigFile = xmldoc(“ospfConfig.xml”)
# Traffic generation
**.lanA.host[0].app[0].typename = “UdpBasicApp”
**.lanA.host[0].app[0].destAddr = “lanB.host[0]”
**.lanA.host[0].app[0].messageLength = 1024B
**.lanA.host[0].app[0].sendInterval = exponential(1s)
- Run the Simulation and Visualize Results
After setting up the network, execute the simulation using OMNeT++. We can envision the network and monitor key performance indicators like packet loss, delay, and bandwidth utilization.
- OMNeT++ delivers a 2D visualization of nodes, links, and traffic flows, enabling you to see how data moves through WAN in real-time.
- Analyse Simulation Results
OMNeT++ delivers built-in tools to record scalar results and vector results for performance evaluation. For WAN simulations, we required to measure the following:
- Throughput: Evaluate the rate at which data is successfully routed over the network.
- Latency/Delay: Evaluate the time it takes for a packet to travel from source to destination.
- Packet Loss: Assess the percentage of packets that are lost because of link errors or network congestion.
- Routing Convergence Time: Evaluate the time it takes for routing protocols such as OSPF to converge after a network change.
Enable result recording in the .ini file:
**.scalar-recording = true
We can measure these outcomes using the OMNeT++ result analysis tool or export the data to external analysis tools such as Python, R, or MATLAB for further processing.
- Extend the Simulation
Once we have the simple WAN simulation set up, we can extend it by:
- Adding more routers and subnets: Replicate larger WANs with multiple interconnected subnets and autonomous systems.
- Simulating network failures: Establish link failures or router outages and monitor how the network adjusts using routing protocols such as OSPF or BGP.
- Testing different QoS (Quality of Service) configurations: replicate WANs with changing bandwidth, traffic shaping, or priority routing.
- Integrating MPLS: Add Multiprotocol Label Switching (MPLS) to enhance WAN performance by permits the effective’s packet forwarding.
Example .ini Configuration for WAN Simulation:
network = WANExample
sim-time-limit = 500s
# WAN link settings
**.routerA.pppg++ <–> routerB.pppg++.datarate = 100Mbps
**.routerA.pppg++ <–> routerB.pppg++.delay = 50ms
**.routerA.pppg++ <–> routerC.pppg++.datarate = 100Mbps
**.routerA.pppg++ <–> routerC.pppg++.delay = 30ms
**.routerB.pppg++ <–> routerC.pppg++.datarate = 50Mbps
**.routerB.pppg++ <–> routerC.pppg++.delay = 60ms
# OSPF routing protocol
**.router[*].routingTable.typename = “OspfRouting”
**.router[*].ospfConfigFile = xmldoc(“ospfConfig.xml”)
# Traffic generation (UDP and TCP)
**.lanA.host[0].app[0].typename = “UdpBasicApp”
**.lanA.host[0].app[0].destAddr = “lanB.host[0]”
**.lanA.host[0].app[0].messageLength = 1024B
**.lanA.host[0].app[0].sendInterval = exponential(1s)
**.lanA.host[1].app[0].typename = “TcpBasicApp”
**.lanA.host[1].app[0].destAddr = “lanB.host[1]”
**.lanA.host[1].app[0].dataAmount = 10MB
**.lanA.host[1].app[0].tOpen = 10s
- Further Customization
We can further customize the simulation by:
- Adding QoS policies: Execute traffic shaping or select the certain kinds of traffic.
- Simulating different WAN technologies: Experiment with fiber optics, satellite communication, or cellular backhaul links.
- Security and VPN simulations: Add VPN tunnels or validates encryption mechanisms over WAN links.
Overall, we had clearly obtainable the detailed description to perform the Wide Area Networks project were given above that were evaluated in OMNeT++ implementation tool. We also further provide the detailed information that related to Wide Area Networks.
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