## 4 Evaluation and Results
### Test Case II: Cross Domain Data Transfer  
Network topology of our first test case is illustrated in Figure 6. This test case consisted of three 40 GE DTNs--BDE1, BDE2, and BDE3. We connected the DTNs to an SDN-enabled network switch (Pica8), and also configured the single or multiple VLANs interfaces on each DTN server. We divided our test case into two logical sites--A and B. Both sites A and B are highlighted in blue and green, respectively. At our SDN-enabled network switch, we configured the port 4/1 as a gateway for site A and port 4/5 as a gateway for site B. To connect both sites (A and B), we simulated a WAN networking by using OSCARS layer 2 circuit to establish the loopback path at the boarder router of each site. The ESNet OSCARS service was used to dynamically set up this loopback path between two sites. The total bandwidth of the loopback path was 1 Gbps and round trip time was approximately 92 ms.  
Figure 5: Extreme-scale evaluation results.  
Figure 6: Cross domain data transfer test case.  
In our evaluation process, we performed the basic data transfer experiments between two sites A and B with the help of a well-known iperf tool, and we used two different classes of traffic in this test case:  
* Priority traffic: In this case, we sent the data from BDE1 data transfer node (192.2.2.1 with vlan2) to BDE3 data transfer node (192.2.2.3 with vlan2). The traffic started at 120 s, and ended at 720 s, wherein the maximum bandwidth was capped at 700 Mbps.
* Best-effort traffic: In this case, data was sent from BDE2 data transfer node (192.4.4.2 with vlan4) to BDE3 data transfer node (192.4.4.3 with vlan4). The traffic started at 0 s, and ended at 600 s.  
Before data transfer started, the BigData Express scheduler established end-to-end paths between DTNs. First, it called the ESNet OSCARS service to establish the loopback WAN path. Then, we dynamically programmed the network at run-time by using the AMQP JSON-RPC primitives of AmoebaNet services. In this experiment, the following tasks were performed by the AmoebaNet service: (a) the campus network's paths calculation and route selection; (b) identified the gateway ports and OSCARS's VLANs IDs at both sites A and B and installed the flow rules for each campus network path; it used 3200/3201 VLAN IDs to connect a campus network with the ESNet OSCARS layer-2 WAN path; and (c) it enforced guaranteed QoS services for priority traffic by dynamically installing the queues and meters.  
Figure 7 shows the evaluation results. It shows that: (a) from 0 s to120 s, best-effort traffic had a throughput close to 1 Gpbs, which implies that it occupied all the bandwidth of the OSCARS WAN path, and (b) from 120 s to 600 s, priority traffic had a throughput of ~700 Mbps while best-effort traffic's throughput decreased to ~300 Mbps. This is because priority traffic had a higher priority. When priority traffic started at 120 s, it would occupy the bandwidth as much as possible until it was capped at 700 Mbps. Best-effort traffic then took the residual bandwidth, which was ~300 Mbps. (c) From 600 s to 720 s, best-effort traffic stopped. Although the total available bandwidth was ~1 Gpbs, priority traffic was still capped at 700 Mbps.  
In this test case, it was clearly demonstrated that the AmoebaNet provided a mechanism for applications to dynamically program the networks at run-time for bulk data transfer jobs, and it could provide \"Application-aware\" networking services as well. AmoebaNet was also able to support differentiated service to ensure the required QoS services for priority traffic. It is also important to note that AmoebaNet had the ability to provision the QoS-guaranteed network paths between two ends with the fastest possible time and provided the enterprise level network services along with the ESNet OSCARS WAN connection.  
Figure 7: AmoebaNet evaluation results.