Abstract-The exhaustion of IPv4 addresses has forced the deployment of the new version of the Internet Protocol (IPv6). However, the migration to the new protocol is done gradually and with the due care for many reasons that include: cost, inclusion of support for IPv6 in existing applications, training of technical staff, lack of web content available over IPv6 from important providers, and obsolete devices not anymore supported by manufacturers. For those reasons, many transition mechanisms have been proposed, each one to fill distinct requirements, with different operational theory and availability according to the network environment. A performance evaluation of these mechanisms can help network administrators and researchers in their selection of the best transition technology for their environment. In this paper, we present a performance comparison of some transition mechanisms such as ISATAP, 6to4, and NAT64 in real testbeds with Debian, Windows 7, Windows 8, and Windows 10. For NAT64, two different tools were tested: TAYGA and Jool. We measure the OWD and the throughput for UDP and TCP for every mechanism, for both Ethernet and Fast Ethernet technologies. From this research, we can conclude that all the modern operating systems for PCs already have good support for IPv6, and a very similar network performance. Also, we can infer from our work that in controlled environments, native IPv4 has the best performance, closely followed by native IPv6. The difference is essentially due to the length of the IP header (20 bytes in IPv4 and 40 bytes in IPv6). The tunneling solutions chosen for this research (ISATAP and 6to4) have a similar performance, which is the lowest of the studied technologies, because of the additional IPv4 header in the tunnel.

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Volume rendering is an important area of study in computer graphics, due to its application in areas such as medicine, physic simulations, oil and gas industries, and others. The main used method nowadays for volume rendering is ray casting. Nevertheless, there are a variety of parallel APIs that can be used to implement it. Thus, it is important to evaluate the performance of ray casting in different parallel APIs to help programmers in selecting one of them. In this paper, we present a performance comparison using OpenGL ® with fragment shader, OpenGL ® with compute shader, OpenCL, and CUDA.

The virtualization of the network access layer has opened new doors in how we perceive networks. With this virtualization of the network, it is possible to transform a regular PC with several network interface cards into a switch. PC-based switches are becoming an alternative to off-the-shelf switches, since they are cheaper. For this reason, it is important to evaluate the performance of PC-based switches. In this paper, we present a performance evaluation of two PC-based switches, using Open vSwitch and LiSA, and compare their performance with an off-the-shelf Cisco switch. The RTT, throughput, and fairness for UDP are measured for both Ethernet and Fast Ethernet technologies. From this research, we can conclude that the Cisco switch presents the best performance, and both PC-based switches have similar performance. Between Open vSwitch and LiSA, Open vSwitch represents a better choice since it has more features and is currently actively developed.

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