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Top1. Introduction
As stated in the abstract, this research deals with modelling an ATM network. To do this we used a piece of simulation software called OPNET Modeler 14.0. This application literally allows you to place such things as switches, servers, client workstations, etc., into a workspace and have them behave just as they would in real life. Hence this particular program is perfect for what we are trying to achieve in this research (Xiao, 2005; Floros, Avlonitis, & Vlamos, 2008; Yasukawa, Forte, & Schulzrinne, 2009; Wang & Zhuang, 2008; Leith, Clifford, Malone, & Ng, 2005; Li, Ni, Malone, Leith, Xiao, & Turletti, 2009).
As also stated earlier, our research on ATM model is based on the ATM model that we built in our research paper. The model is explained in-depth (Abusubaih, Wiethoelter, Gross, & Wolisz, 2008; Brian & Mark, 2007).
Figure 1 shows the high-level perspective of the ATM model that was produced in research Lab. The model consists of 8 main components: 2 central ATM cross connection switches, 4 subnets, an application config and a profile config.
Figure 1. High level view of the ATM network model
As shown in Figure 1, the subnets are each connected to one of the cross connection switches (NorthWest & SouthWest to the CentralWest switch; SouthEast & NorthEast to the CentralEast switch). Both central switches are then connected to each other; utilising a total of 5 links altogether. These links are all full-duplex (bidirectional) ATM connection links. The application config “Applications” houses the definitions for all the applications that will be used in our model. In our research Lab ATM model three definitions have already been setup; these are definitions for Email, and FTP. The profiles config “Profiles” houses the rules and settings for applications. So in this case there will be four profiles – one for each application definition outlined in the application config.
Figure 2 shows the components and subsequent layout of the NorthWest subnet. Each of the subnets has identical components and layout as that of the Northwest subnet. Each has 2 ATM Data (Email & FTP) client workstations, a central ATM cross connection switch, and an ATM server. Each client is connected individually to the central switch; and so is the server. These links are also all full-duplex ATM connection links.
Figure 2. Internal view of the “NorthWest” subnet
The central switch is then also connected to the network outside of the subnet. As stated each subnet is connected to a switch, so the central switch inside the subnet thus is connected to one of the central switches outside of the subnet (e.g., CentralWest switch). This connection is also made via a bidirectional ATM link. Thus, altogether, there are 8 links being utilised within a subnet
Top2. Node Configuration (Station, Switch, Server)
In this model, there are a total of 34 nodes. The categorical breakdown of them is as follows: