Network simulator version 2
Network simulator version 2 is A best example of discrete event driven simulation. Physical activities translate to events in a discrete-event driven simulation. In the order of the schedule occurrences the events are queue and process in Network simulator version 2. Time progress as the events process. Introduction  1 2 Time: 1.5 sec Time: 1.7 sec Time: 1.8 sec Time: 2.0 sec. Components of Network simulator version 2 are ns, the simulator itself nam.
The Network Animator visualizes ns (or other) output GUI input simple ns scenarios Pre-processing: traffic and topology generators Post-processing: simple trace analysis, often in Awk, Perl, or Tcl on version 2.
The main theme of using Network version-2 is to generate the simulation environment.
Network-simulator is very reliable and provides efficient simulation to the user.
- Network simulator version 2 is to support networking research and also education.
- Protocol design, traffic studies, etc are also uses simulation.
- Protocol-comparison is also possible in Network – 2.
- New architecture designs also support.
- To provide collaborative environment
- Network version is also freely distribute, open source.
- Increase conﬁdance at the result of simulation.
- Network is also used to build the network structure and topology
- The simulation environment which is also just the surface of your simulation
- Easy to conﬁgure your network parameter also in network simulation.
Potentially, a wide range of benefits can also achieve by Content-centric networking. The benefits include simpler configuration of network devices, content caching to reduce congestion and also improve delivery speed, and building security into the network at the data level. However, for certain types of network activities posed the change of communication paradigm problem. But recent research indicates these applications are feasible also for instance real-time multimedia applications.
Furthermore, building content routers that also support content-centric networking at high speed is still an open problem to solve that also has gain research interest only recently.
The client components are running on other device where each service is usually provide also by a server component running on one or more computers (often a dedicated server computer offering multiple services) and accessed via a network. However, the same machine can also run both the client and server components. Clients and also servers will often have a user interface and also sometimes other hardware associate with them.
A multi-user version of the popular orthogonal frequency-division multiplexing (OFDM) digital modulation scheme is refer as Orthogonal Frequency-Division Multiple Access (OFDMA). By assigning subsets of subcarriers to individual users can also achieve by OFDMA multiple access as shown in the illustration below. This OFDMA allows simultaneous low data rate transmission from several users also in a network.
Adaptive user-to-subcarrier assignment can also achieve based on feedback information about the channel conditions also in adaptive network. This further improves the OFDM robustness also to fast fading and narrow-band co-channel interference when the assignment is also done sufficiently fast. Based on feedback information we can make it possible to achieve even better system spectral efficiency. In view also to support differentiated Quality of Service (QoS) different numbers of sub-carriers can assign to different users in a given network. The sub-carriers of Quality of Service (QoS) include control also the data rate and error probability individually for each user in a network.