Jun 20, 2018 2 Best Free Network Simulator Software for Windows: Cisco Packet Tracer. Cisco Packet Tracer is one of the best free network simulation software that you can use. Basically, it is used for training network professionals and it is quite old and popular as well. It offers a large number of network devices like routers, hubs, switches, terminals, etc.
In computer network research, network simulation is a technique whereby a software program models the behavior of a network by calculating the interaction between the different network entities (routers, switches, nodes, access points, links etc.). Most simulators use discrete event simulation - the modeling of systems in which state variables change at discrete points in time. The behavior of the network and the various applications and services it supports can then be observed in a test lab; various attributes of the environment can also be modified in a controlled manner to assess how the network / protocols would behave under different conditions.
Network simulator[edit]
A network simulator is software that predicts the behavior of a computer network. Since communication networks have become too complex for traditional analytical methods to provide an accurate understanding of system behavior, network simulators are used. In simulators, the computer network is modeled with devices,links, applications etc. and the network performance is reported. Simulators come with support for the most popular technologies and networks in use today such as 5G, Internet of Things (IoT), Wireless LANs, mobile ad hoc networks, wireless sensor networks, vehicular ad hoc networks, cognitive radio networks, LTE etc.
Simulations[edit]
Most of the commercial simulators are GUI driven, while some network simulators are CLI driven. The network model / configuration describes the network (nodes, routers, switches, links) and the events (data transmissions, packet error etc.). Output results would include network level metrics, link metrics, device metrics etc. Further, drill down in terms of simulations trace files would also be available. Trace files log every packet, every event that occurred in the simulation and are used for analysis. Most network simulators use discrete event simulation, in which a list of pending 'events' is stored, and those events are processed in order, with some events triggering future events—such as the event of the arrival of a packet at one node triggering the event of the arrival of that packet at a downstream node.
Network emulation[edit]
Network emulation allows users to introduce real devices and applications into a test network (simulated) that alters packet flow in such a way as to mimic the behavior of a live network. Live traffic can pass through the simulator and be affected by objects within the simulation.
The typical methodology is that real packets from a live application are sent to the emulation server (where the virtual network is simulated). The real packet gets 'modulated' into a simulation packet. The simulation packet gets demodulated into a real packet after experiencing effects of loss, errors, delay, jitter etc., thereby transferring these network effects into the real packet. Thus it is as-if the real packet flowed through a real network but in reality it flowed through the simulated network.
Emulation is widely used in the design stage for validating communication networks prior to deployment.
List of network simulators[edit]
![Network Simulation Software For Mac Network Simulation Software For Mac](/uploads/1/2/6/4/126467430/719831344.png)
There are both free/open-source and proprietary network simulators available. Examples of notable network simulators / emulators include:
![Network Simulation Software For Mac Network Simulation Software For Mac](/uploads/1/2/6/4/126467430/254531417.jpg)
Uses of network simulators[edit]
Network Simulator
Network simulators provide a cost-effective method for
- Network design validation for enterprises / data centers / sensor networks etc.
- Network R & D (More than 70% of all Network Research paper reference a network simulator)[citation needed]
- Defense applications such as HF / UHF / VHF Radio based MANET Radios, Tactical data links etc.
- LTE, LTE Advanced, IOT, VANET simulations
- Satellite communication
- Optimization of cache placement on large virtual content distribution networks
- Education - Online courses, Lab experimentation and R & D. Most universities use a network simulator for teaching / R & D since its too expensive to buy hardware equipment
There are a wide variety of network simulators, ranging from the very simple to the very complex. Minimally, a network simulator must enable a user to
- Model the network topology specifying the nodes on the network and the links between those nodes
- Model the application flow (traffic) between the nodes
- Providing network performance metrics as output
- Visualization of the packet flow
- Technology / protocol evaluation and device designs
- Logging of packet/events for drill down analyses / debugging
See also[edit]
References[edit]
External links[edit]
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Network_simulation&oldid=954198377'
Network emulation is a technique for testing the performance of real applications over a virtual network. This is different from network simulation where purely mathematical models of traffic, network models, channels and protocols are applied. The aim is to assess performance, predict the impact of change, or otherwise optimize technology decision-making.
Methods of emulation[edit]
Network emulation is the act of introducing a device to a test network (typically in a lab environment) that alters packet flow in such a way as to mimic the behavior of a production, or live, network — such as a LAN or WAN. This device may be either a general-purpose computer running software to perform the network emulation or a dedicated emulation device which usually does link emulation.
Network emulators incorporate a varying amount of standard network attributes into their designs including: the round-trip time across the network (latency), the amount of available bandwidth, a given degree of packet loss, duplication of packets, reordering packets, corruption and modification of packets, and/or the severity of network jitter.
It is commonly known that networks are imperfect — private or public. They introduce delay, errors and drop packets. The primary goal of network emulation is to create an environment whereby users can connect the devices, applications, products and/or services being tested in order to validate their performance, stability, or functionality against real-world network scenarios. Once tested in a controlled environment against actual network conditions, users can have confidence that the item being tested will perform as expected.
Emulation, simulation and traffic generation[edit]
Emulation differs from simulation in that a network emulator appears to be a network; end-systems such as computers can be attached to the emulator and will behave as if they are attached to a network. A network emulator mirrors the network which connects end-systems, not the end-systems themselves.[1]
Network simulators are typically programs which run on a single computer, take an abstract description of the network traffic such as a flow arrival process and yield performance statistics such as buffer occupancy as a function of time.
These products are typically found in the Development and QA environments of Service Providers, Network Equipment Manufacturers, and Enterprises.
Network emulation software[edit]
Software developers typically want to analyze the response time and sensitivity to packet loss of client-server applications, and emulate specific network access (802.11 n, ac / 4G / Tactical data links etc.) with different round-trip-time, throughput, bit error rate, network drop outs and application dropouts . Emulators for this purpose come in many different forms including browser-based or integrated development environment appliances.
Two open source network emulators are Common Open Research Emulator (CORE) and Extendable Mobile Ad-hoc Network Emulator (EMANE). They both support operation as network black boxes, i.e. external machines/devices can be hooked up to the emulated network with no knowledge of emulation. They also both support both wired and wireless network emulation with various degrees of fidelity. CORE is more useful for quick network layouts (layer 3 and above) and single machine emulation. EMANE is better suited for distributed high fidelity large scale network emulation (layers 1/2).
The most popular network simulation software packages, OPNET and Tetcos NetSim, also have emulation modules for real time interconnects. In general simulation tools with emulation capabilities provide more sophistication than emulation devices. Emulation devices only provide for emulation of the physical link and do not factor in the effects of the higher layers (MAC, network, transport etc). Simulation tools however factor in effects from the entire network stack when running in emulation mode. They would allow for connecting multiple sources / destinations, Routing, support for multi cast traffic, MANET protocols etc.
Traffic generation software[edit]
Network Simulation Software For Mac Free
The network performance under maximum throughput conditions can be analysed by network traffic measurement in a testbed network, using a network traffic generator such as iperf. The traffic generator sends dummy packets, often with a unique packet identifier, making it possible to keep track of the packet delivery in the network using a network analyzer.
See also[edit]
References[edit]
- ^'Network simulation or emulation?'. Network World. Network World. Retrieved 22 September 2017.
Further reading[edit]
- Beuran, Razvan (2012). Introduction to Network Emulation. Pan Stanford. ISBN978-981-4310-91-8.
External links[edit]
Network Simulation Software For Mac Free
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Network_emulation&oldid=958661138'