## 5 Experiments and Analyses  
Figure 9 and Table 9, respectively, show the topology and specifications of the experimental environment of this study. The MCI server consists of three desktop computers individually acting as Information Manager, Resource Broker and Data Center. Six user nodes are currently connected to the MCI server through a wireless network. Node IDs (rather than node IP) are the sequences in which they enter the system. Their initial performance table is shown in Table 10. All user nodes run the Ubuntu 10.07 operating system [22], globus tookit 5.0.2 [23], Ganglia 3.1.7 [18] and NWS 2.13 [20]. Assume that initial CLWQs and CPU utilization rates of all nodes are zero.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Node IP**} & **CPU** & \multirow{2}{*}{**AMS**} & **CLWQ** & **CUR** & \multicolumn{2}{c}{**Network**} & \multirow{2}{*}{**Status**} & **Perfor.** & **Perfor.** & **Origin-** & **Infor.** \\  & **level** & & & & & & **bandwidth** & & **score** & **level** & **perf-level** & **Manage. No.** \\ \hline
172.15.230.5 & 1 & 4 & 3 & 3 & 4 & idle & 17 & 1 & 1 & A \\
172.15.230.6 & 1 & 2 & 3 & 3 & 4 & idle & 15 & 2 & 2 & A \\
172.15.230.7 & 1 & 1 & 4 & 4 & 4 & idle & 14 & 3 & 3 & A \\
172.15.230.8 & 1 & 4 & 3 & 3 & 4 & idle & 17 & 1 & 1 & A \\
172.15.230.9 & 1 & 2 & 4 & 4 & 4 & idle & 15 & 2 & 2 & A \\
172.15.230.10 & 1 & 1 & 4 & 4 & 4 & idle & 14 & 3 & 3 & A \\ \hline \hline \end{tabular}
\end{table}
Table 10: The initial performance table.  
Figure 9: The experimental topology.  
\begin{table}
\begin{tabular}{c|c c c} \hline \hline \multirow{2}{*}{**Node Attribute**} & \multirow{2}{*}{**CPU frequency**} & \multirow{2}{*}{**Memory**} & \multirow{2}{*}{**Node IP**} \\ \hline
1 & AMD Athlon64 X2 Dual-core 2.0 GHz & 4096 MB & 172.15.230.5 \\
2 & Intel Centrino 1.86 GHz & 1024 MB & 172.15.230.6 \\
3 & Intel Celeron 1.6 GHz & 512 MB & 172.15.230.7 \\
4 & AMD Athlon64 X2 Dual-core 2.0 GHz & 4096 MB & 172.15.230.8 \\
5 & Dual-core 2.0 GHz & 1024 MB & 172.15.230.9 \\
6 & Intel Celeron 1.6 GHz & 512 MB & 172.15.230.10 \\ \hline \hline \end{tabular}
\end{table}
Table 9: The user nodes’ specifications.  
Five experiments were performed in this study. The first evaluated the turnaround time of a user request and a number of user requests allocated to different resource nodes for different tested schemes in the situation where a user request requests a resource node to deliver a video program. The second studied the performance of the tested schemes given different packet sizes. The third and the fourth redid the second experiment given different data rates, and different numbers of requests per second, respectively. The fifth experiment redid the second experiment when different numbers of nodes leave/re-enter the system at different time points. Here, throughput is defined as the average number of bits received per second. Packet drop rate is defined as (the number of packets sent--the number of packets received)/ (the number of packets sent). Turnaround time of a request, denoted by \(T_{\text{ta}}\), is defined as \(T_{\text{ta}}=T_{\text{r}}+T_{\text{tra}}+T_{\text{ex}}\) where \(T_{\text{r}}\) is the time required to transfer the request from the request node to the Resource Broker through the MCI server, \(T_{\text{tra}}\) is the time that the request spends to travel from the Resource Broker to a resource node, and \(T_{\text{ex}}\) is the time required to execute the job on the resource nodes. According to our estimation, \(T_{\text{r}}=0.14\) ms (\(=1.5\) kbits/\(11\) Mbps), \(T_{\text{tra}}=T_{\text{r}}\) and \(T_{\text{ex}}=125+7.27\) s in which \(125\) s is the time for Video program initialization and \(7.27\) (\(=10\) MB/\(11\) Mbps) s is the transmission time of the program.