Virtual networks: isolation, performance, and trends

Abstract

Currently, there is a strong effort of the research community in rethinking the Internet architecture to cope with its current limitations and support new requirements. Many researchers conclude that there is no one-size-fits-all solution for all of the user and network provider needs and thus advocate for a pluralist network architecture, which allows the coexistence of different protocol stacks running at the same time over the same physical substrate. In this paper, we investigate the advantages and limitations of the virtualization technologies for creating a pluralist environment for the Future Internet. We analyze two types of virtualization techniques, which provide multiple operating systems running on the same hardware, represented by Xen, or multiple network flows on the same switch, represented by OpenFlow. First, we define the functionalities needed by a Future Internet virtual network architecture and how Xen and OpenFlow provide them. We then analyze Xen and OpenFlow in terms of network programmability, processing, forwarding, control, and scalability. Finally, we carry out experiments with Xen and OpenFlow network prototypes, identifying the overhead incurred by each virtualization tool by comparing it with native Linux. Our experiments show that OpenFlow switch forwards packets as well as native Linux, achieving similar high forwarding rates. On the other hand, we observe that the high complexity involving Xen virtual machine packet forwarding limits the achievable packet rates. There is a clear trade-off between flexibility and performance, but we conclude that both Xen and OpenFlow are suitable platforms for network virtualization.

Virtual Network Performance Evaluation for Future Internet Architectures

“…We present three of the most well-known available hypervisors: VMware, Xen, and OpenVZ. VMware and Xen are hardware virtualization systems that virtualize hardware resources such as CPU, memory, and I/O guaranteeing high flexibility and isolation between the virtualized systems [2]. OpenVZ, however, claims to be a lightweight virtualization platform because it virtualizes the OS kernel, creating multiple isolated user spaces [13].…”

OMNI: OpenFlow MaNagement Infrastructure

“…This OMNI application is an extension of the Switchstats application provided with NOX. The original Switchstats application requests switches to provide a description of the switch, the number of packets received and lost by each switch port and also by each switch flow table, but it does not provide any information about flows, because NOX does not implement flow statistic requests 2 . Therefore, we extended the Switchstats application as well as NOX to request information about individual instantiated flows and also about aggregated flows, such as a description of each flow, the number of sent packets, the number of lost packets and the duration of each flow.…”

“…Hence, since it is an open standard, OpenFlow supports innovation and enables the development of new control mechanisms and experiments in real environments [2]. Nevertheless, OpenFlow demands tools to simplify management and to facilitate the development of control mechanisms.…”

OpenFlow and Xen-Based Virtual Network Migration

“…There are two basic approaches for virtualizing a network element [5]. Next, we show how the migration process works, according to the virtualization approach in use.…”