Packet switching refers to a digital networking communications method in which all the data transmitted is grouped into blocks called packets before it is sent. Packet switching applies to all transmitted regardless of its type, content or structure. The data is transmitted over a shared network and transverses through a network of switches, adapters, routers and other network nodes (OPTNET Technologies, 2010). Packets of data are transmitted individually to their destination using different routes. Once all the packets forming a message get to the destination they re-compile into the original message. Common protocols using the packet switching technologies include Wide Area Network (WAN)-Frame relay and TCP/IP, X.25.
Objectives
The principal objective of this lesson was to model a simple network that can be measured by the end-to-end delay experienced by traffic on the network. The specific objective was to model a simple network in which four peripheral nodes to generate traffic while a central hub node relays the traffic to the appropriate destination within the network (OPTNET Technologies, 2010). This would involve the simulation of the behavior of a packet switching network. The study would involve creating a network using link editors, learn new kernel procedures. Moreover, the study would enhance familiarity with processes and node models as well as other principles of model design.
Results
The results of the experiment were chosen during the simulation. The desired results were to present end-to-end and link utilization characteristics of the switch. The statistics defined in the peripheral node’s process model were obtained under global statistics after running the software used to operate the packet switching connection. When configuring two simulation runs, the source processor created packets of constant size. In combination with the fixed data rate of the point-to-point transmitters and receivers results in a fixed end-to-end delay for the packets, (OPTNET Technologies, 2010). When the packets were sent to a transmitter quickly, some of the packets are delayed in the transmitter’s queue. When the packet inter-arrival time was varied, the end-to-end delay would be affected.
Discussions
The packet format editor is used to operate and analyze the results obtained during the simulations. The format editor analyses and compares the end-to-end and the utilization between the two simulations runs (OPTNET Technologies, 2010). Viewing the results and under the expanded statistics tree showed two graphs corresponding to the two simulation runs for that scenario.
The graphs showed that a large reduction in packet generation resulted in a corresponding reduction in link utilization, (OPTNET Technologies, 2010). It was possible to select the data one wants from the list of available data files. By right-clicking in the workspace and choosing “view results”, the results browser opened to list results for the simulation runs. By expanding the statistics tree, two graphs corresponding to the simulation runs were displayed. By setting the graphing option “overlaid statistics” and then selecting the “time average”, the statistics for the both output vector files were checked. The time-averaged utilization graph is displayed. However, a large reduction in packet generation results in a corresponding reduction in link utilization, (OPTNET Technologies, 2010). The linear graphs plotted do not clearly show the delay experienced by individual packets. This can be corrected by changing the draw style to discrete style.
Packet switching is beneficial packets are short. The communication links connecting the nodes are allocated to transfer single messages for shorter periods of time during the transmission of each packet. Sending longer messages requires a series of packets when being sent. This however, does not require a link to be placed in between the transmissions of single packet. This implies that packets affiliated to other messages may also be sent in between packets of another message which is being sent from one point to another. This way, resources can be shared in a fairer way via each link. Moreover, packet switching allows “Pipelining”. In a connection with four points, A, B, C and D and packets numbered 1-4. All the packets can be sent simultaneously between the four points. The simultaneous utilization of several communication links represents increased efficiency. The overall delay in the transmission of information across a typical packet network is in most cases considerably less than that spent in message switching. This is in spite of each packet in the case of message switching bearing a header.
Conclusion
Packet switching is a digital networking method in which all data regardless of its type, content and structure is grouped into suitably-sized blocks called packets before it is sent. This experiment was aimed at modeling a simple network using four peripheral nodes to generate traffic and utilize a central hub node to relay the traffic to the appropriate destination in the network. Packet editor software was used to analyze the end-to-end and the link simulations generated. When configuring two simulation runs, the source processor generated packets of constant size while combination of the simulation runs with fixed data rate of the point-to-point data results in delayed fixed end-to-end transmission of the packets. Graphs are displayed in linear and discrete styles. The discrete style graph is used to correct the large reduction in packet generation and the corresponding reduction in link utilization. Packet switching is beneficial because in results increased efficiency in the transmission of data.
References
OPTNET Technologies, 2010. Modeler tutorials-packet switching 1.
