## 5 Experimental Results
### Experimental Results for BCC Algorithm
#### 5.2.3 Performance Analysis of BCC  
Here we present the network-level performance of the S2S-WiDCN with BCC along with a comparative analysis with respect to wired fat-tree DCNs in terms of throughput.  
The throughput was defined as the average rate of bit transferred per second over the DCN. The normalized throughput of both S2S-WiDCN and fat-tree architecture for different injection rates at NC, CES, GRD and BCC consolidation are shown in Figure 9. Normalized throughput was defined as the ratio of the average throughput achieved and average injection rate. For NC, although it was seen that for lower injection rate both S2S-WiDCN and fat-tree network showed similar throughput, but for  
Figure 8: Power consumption comparison of different architecture for (**a**) no consolidation (NC) (**b**) clustered exhaustive search (CES) (**c**) Greedy approach base consolidation (GRD) and (**d**) bandwidth constrained consolidation (BCC). The arrows denote the power saving due to BCC.  
Figure 7: Power profile with varying utilization of PowerEdge C5220 server [52].  
both the networks, the achieved throughput started to decrease as the average injection rate went beyond 100 Mbps. However, degradation was different for wired and wireless DCNs. The throughput reduced more for the wireless DCN than the wired counterpart for higher injection rates due to the lower physical bandwidth available per channel for the wireless links of 0.563 Gbps compared to 1.0 Gbps for the wires. Further, from Figure 9, it can be seen that, for the lower injection rates, there was no significant difference in achieved throughput with BCC consolidation for both wired and wireless data centers. These throughputs were also similar compared to that NC case. However, for higher injection rates beyond 100 Mbps, for both S2S-WiDCN and fat-tree network, achieved throughput increased compared to the NC. The main contributing factor was that, due to the VM migrations, in many cases, both source and destination of flows ended up in the same physical server. Therefore, these flows are effectively eliminated from the network, which ultimately increased the average throughput of the entire network compared to NC. On the other hand, instead of BCC, if CES or GRD consolidation was implemented, at lower injection rates, there was no significant difference in achieved throughput for both S2S-WiDCN and fat-tree networks compared to BCC. For the higher injection rates beyond 100 Mbps, the performance of the wireless networks improved compared to NC, but not as well as BCC. However, the performance of the wired network degraded with the incorporation of CES or GRD consolidation algorithm. This contrasting behavior was mainly due to the number of channels available in different architectures. Due to all flows in the wired data center being channelized over the same link, the aggregate flow rate after CES or GED exceeded the physical link bandwidth violating (5). This caused degradation in throughput. On the contrary, in the S2S-WiDCN, due to the presence of multiple vertical sectors and the horizontal link a relatively larger number of flows did not violate (5) resulting in better performance compared to the wired data center.