Unlocking the power of OPNET modeler / Zheng Lu, Hongji Yang. p. cm. Simulation statistical results can be exported to PDF Editor for analysis as well. You. Unlocking the Power of OPNET Modeler. Unlocking . Access. PDF; Export citation 2 - Installation of OPNET Modeler and setting up environments. pp Unlocking the Power of OPNET Modeler Zheng Lu, Download PDF Proceedings of the Summer Computer Simulation Conference, SCSC Book.
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Pages · · MB · 79 Downloads ·English. Preview Pages· · MB·, Downloads Unlocking the Power of OPNET Modeler. Unlocking Power OPNET Modeler is hosted at free file sharing service 4shared. PDF Ebook Acca Past Papers Free Download, Save or Read Online Acca. We propose to use OPNET Modeler , and in particular the custom application to this architecture, the requirement of computational power and bandwidth for a .. Z. Lu and H. Yang, Unlocking the Power of OPNET Modeler,. Cambridge.
OPNET During the last decade there has been a detonation of devices using sensor technologies for control and monitoring purposes.
Wired Sensors are now projected to be replaced with wireless technologies. The corporate have been envisioning of a digital home where every device is connected, and remotely controlled and monitored. Even though a perfect digital home is yet a mirage, we are now able to apply several technologies to suite our home and industrial networking needs.
However, this concept of a digitally connected home has received a luke warm response due to lack of feasible solutions. Over the years, several possible nominees have been identified.
But none match the robustness and reliability required for the automation applications. Sturdiness when it comes to critical application scenarios as applicable to industrial needs and reliability when it comes to power usage and prompt response . ZigBee is a specification for a set of high level communication protocols used to create personal area networks built from tiny, low-power digital radios and the computer connected.
Though low-powered, ZigBee devices can transmit data over long distances by passing data through median devices to reach the distant ones, creating a mesh network i.
The decentralized nature of such wireless ad-hoc networks make worthy applications where a central node can't be pivoted .
Unlocking the power of OPNET modeler
ZigBee is used in applications that require only a low data rate, long battery life, and secure networking. Applications include wireless light switches, electrical meters with in-home-displays, traffic management systems, and other consumer and industrial equipment that requires short-range wireless transfer of data at relatively low rates.
ZigBee networks are secured by bit symmetric encryption keys. The results obtained are put in context of the previous work done on the scalability of RSVP. It is found that the Summary Refresh extension considerably improves the performance of the protocol both in terms of message processing and message generation. All rights reserved. A major concern regarding RSVP is the fact that it suffers from a severe scalability problem. Because RSVP uses a soft state approach in maintaining reservations, messages have to be retransmitted within a certain period so that reservations do not time-out.
This periodic retransmission of messages and state lookup introduces considerable processing overhead and causes the scalability problem of the protocol. The main goal of this paper is to present a performance evaluation of RSVP from a scalability point of view.
Pana, F. An overview of the most important network simulation tools is presented in . The simulation study should not be seen as a substituent of previous results, but rather as another piece of the puzzle that completes the understanding of the scalability problem of RSVP. Insights about the performance capabilities of RSVP and its extensions are revealed and situated in the context of related work [7,8].
Different pitfalls encountered in conducting this simulation study are also illustrated. The rest of the paper is structured as follows.
Unlocking the Power of OPNET Modeler
Section 2 summarizes previous related work. In Section 4 we describe the approach used in conducting the simulation study. In Section 5 we discuss the obtained results and situate them in the context of previous research.
Related work There are many papers that mention the scalability problem of RSVP [9—14] but only a few actually analyze this issue [15,7,16]. To our knowledge, at this point there is no simulation study of the RSVP scalability problem. The papers that discuss the scalability issue of RSVP are based on a very limited test case and a very simple topology, and do not use simulation. We do not argue the utility of the results obtained using such a real case scenario, but a series of limitations and drawbacks emerge from this approach .
Moreover, previous work that assesses the performance or the scalability of RSVP concentrates mainly on the core design of the protocol. In the mean time the IETF has introduced a number of extensions specially focused on improving the scalability of the protocol [18,19].
The most notable scalability extensions are the Bundle and the Summary Refresh Srefresh extension .
Other papers evaluate various aspects of RSVP performance, e. However, none of them focuses on the actual scalability of the protocol. A more complete list of papers that analyze distinct enhancements of RSVP can be found in .
The QoS obtained by utilizing RSVP as a capacity admission procedure under a new proposed service differentiation model is presented in [27,28]. If a matching state is found, then the expiration time of the state is updated and the message is destroyed.
Performance evaluation of RSVP using OPNET Modeler
If however, no state is found, a new state is created that corresponds to the information from the Path message. The same procedure is followed also for the Resv messages.
If no Path state is found an error message is generated. If this is not the case then the expiration time of that state is simply updated.
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First, all the Path states maintained by the node are scanned, and the ones that are expired are deleted expired means that current simulation time is bigger than the expiration time of the state. Afterwards, for each maintained Path state that is not expired a Path refresh message is generated.
Second, the Resv states are scanned and the expired ones are deleted. The generation of the Resv refresh messages is started next. If a matching reservation state exists, then the reservation state is refreshed by sending a Resv refresh message towards the previous hop.
A Bundle message contains a variable number of standard RSVP messages, but should contain at least one sub-message. Bundle messages can only be sent between RSVP neighbors that support this extension.
In this implementation a Bundle message is created every time a refresh message is created for a particular interface and no Bundle message exists for that interface. In other words, irrespective of the time period that passed since the last bundle message was generated, a new Bundle message is created only when a RSVP refresh message needs to be bundled. The refresh procedure presented earlier for the original RSVP design will be the basis of our Bundle extension.
If a Bundle message already exists for that interface the Path message is created and bundled as a submessage.
The same process will be used by the Resv refresh messages as well. The maximum theoretical size allowed for a Bundle message is the maximum size of one IP datagram such that the datagram is not fragmented by IP.
Bundle messages are also sent when the hold timer of the message expires. Bundle messages are sent hop-by-hop as raw IP datagrams. Each time a Bundle message is received by a node, the respective node processes every individual sub-message bundled within as if normal Resv and Path messages were received.
The Summary Refresh extension allows refreshing of Path and Resv states without the full retransmission of standard Resv and Path messages.
The extension is designed only for refresh messages Path and Resv. Each time the refresh timer expires, Srefresh messages are generated and sent for each interface that has RSVP Summary Refresh enabled. However, if the value is greater, then that Srefresh message is sent, and a new Srefresh message is generated for the current ID.
The process described above is done for all the Path and Resv states of the node. The matching of the state is based on the ID and on the source address of the Srefresh message by searching through all the existing states.The extension is designed only for refresh messages Path and Resv. However, since the CRL distribution is one of the key problems faced by each PKI, the focus of the analysis is put on this issue. On Fig. These changes will be applied on all the nodes bearing same characteristics.
First, all the Path states maintained by the node are scanned, and the ones that are expired are deleted expired means that current simulation time is bigger than the expiration time of the state. Because RSVP messages are sent in an unreliable way, the periodic refresh messages are used also for recovering from possible packet loss.