- Applications are the sources of traffic in the network. This traffic is modeled as individual packets.
- These packets flow from the source to the destination over the designed network. As it flows through the network, depending on the devices, link bandwidths, and networking protocols, the packets would experience network effects such as delay, error, loss, etc.
- Applications are generally parameterized in terms of packet size, inter-packet arrival time, priority, transport protocol running below, etc.
- Each application has its distinctive traffic pattern and creates its unique load on the network.
- NetSim allows users to model and simulate different types of applications like CBR, Custom, FTP and HTTP, etc.
In this example, we explain the parameters for getting the same throughput for CBR and FTP applications. Note that:
- In CBR Application we configure the Packet-size.
- Whereas in FTP we configure the File-size.
- Traffic Generation Rate for CBR.
Generation Rate (Mbps) =(Packet Size (bytes) * 8)/ Inter arrival Time(micro sec)
- For FTP
Generation Rate (Mbps) =(File Size (bytes) * 8)/ Inter arrival Time(micro sec )
- If we want to configure 'equivalently' for both CBR and FTP applications, then for a given FTP-IAT and FTP-File-Size set, the CBR settings should be
CBR-Packet-Size(Bytes) = 1460
CBR-Inter-arrival_time (mircoseconds) = (1460 * 1,000,000 * FTP-IAT(seconds) /FTP-File-Size (B))
Case 1 - For FTP Application
- Network Scenario:
- Application Settings
Application Properties
Application Type
FTP
Source ID
1
Destination ID
2
Transport Protocol
UDP
Packet Size
1,250,000 Bytes
IAT
5 sec
Case 2 - For CBR Application
- Network Scenario:
- Application Settings:
- CBR IAT = (1460 * 1,000,000 * 5 / 1,250,000)
- CBR IAT = (1460 * 1,000,000 * 5 / 1,250,000)
Application Properties | |
Application Type | CBR |
Source ID | 1 |
Destination ID | 2 |
Transport Protocol | UDP |
Packet Size | 1460 Bytes |
IAT | 5840 micro sec |
- Simulation time is 100 sec for both cases
Results Comparison for CBR and FTP Applications: You will get approximately the same throughput if you run the simulation for a long time. There will be a small difference because in FTP the entire file is generated in the beginning but in CBR packets are generated every IAT
Application Type | Throughput (Mbps) |
CBR | 1.99 |
FTP | 1.99 |