For the next set of tests, we evaluated and compared the scalability performance of the Ensemble Connector and OVS implementations. As with any switch, the virtual switch should support basic Layer 2 features, including MAC learning. The challenge here is that as the number of MAC addresses learned from incoming traffic grows, so the performance of the switch can degrade. This is specifically relevant for the software-based solutions that lack comparable hardware-accelerated lookup caches.
We performed a series of throughput tests using virtual switch only, and without a VNF, using the same methodology as for the throughput tests described in the previous section. The service interconnecting the physical test ports on the DUT was configured as E-LAN, forcing it to learn the MAC addresses.
We performed three test runs for each device and frame size, with 2,600 and 1,200 MAC addresses, evenly distributed among the ports (1,300 and 600 addresses per port, respectively). The first configuration is identical to the configuration used in the previous throughput test. The other two runs provide a comparison on how much the performance is affected by increasing the number of MAC addresses.
At the beginning of the test, the analyzer transmitted learning frames for each of the simulated MAC addresses, filling the MAC address table of the device. Using the CLI of the Ensemble Connector, we verified that the device learned the exact number of MAC addresses as defined by our configuration.
Afterwards, we performed an RFC2544 throughput test between two test interfaces, exchanging up to 2 Gbit/s of traffic full-mesh between all simulated MAC addresses. As in the previous tests, we performed latency measurements.
The results of the tests are presented in the tables and diagrams below. This time, the difference between Ensemble Connector and OVS implementations was much more obvious.
On Ensemble Connector, we observed only a minor degradation of the throughput performance and higher latency in case of the 64-byte frames. In all other cases the DUT showed a 100% line-rate performance and nearly constant latency.
On OVS implementation however, we saw a major degradation of performance with the rising number of MAC addresses. The DUT did not reach full line-rate performance for the packet sizes below 1024, which was possible with just two active MAC addresses. The latency also grew to become relatively very high, reaching close to 12 milliseconds.
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