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We outline a policy conflict analysis process for the analysis of newly specified federation-level policies against previ ously deployed 10caVfederation policies. The process is generic in the sense that it can be employed by each domain participating in a federation to help maintain the consistency of their local system with that of the federation. The conflict analysis process utilises an information model and associated ontology for representing both the static and dynamic application-specific aspects of the local operating environment and the federation to aid in the detection of potential inconsistencies. It employs two algorithms, one for the selection of previously deployed policies related to the federation-level policy and the other for analysing the returned policies against the federation-level policy. The selection algorithm reduces the number of deployed policies required to be retrieved for analysis against any newly specified federation-level policy, while the conflict analysis algorithm detects inconsistencies relating to the conditional element of a policy rule. We discuss a concrete example in the form of a federated XMPP communication scenario.

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Abstract-Virtualization is an enabling technology that improves scalability, reliability and flexibility. Virtualized networking is tackled by emulating or paravirtualizing Network Interface Cards (NICs). This approach, however, leads to complexities (implementation and management) and has to conform to some limitations imposed by the Ethernet standard. The Recursive InterNetwork Architecure (RINA) turns the current approach to virtualized networking on its head: instead of emulating networks to perform inter process communication on a single processing system, it sees networking as an extension to local inter-process communication. In this article, we show how RINA can leverage a paravirtualization approach to achieve a more manageable solution for virtualized networking. We also present experimental results performed on IRATI, the reference open source implementation of RINA, which shows the potential performance that can be achieved by deploying our solution. I. INTRODUCTIONVirtualization technologies provide a cost-effective way of increasing the scalability, reliability and flexibility of services deployed over the internet. Virtual Machine networking, the way a VM connects to the physical network, is an aspect of high importance in the virtualization world, with network performance being paramount [1]. The traditional way that hypervisors implement VM networking is based on NIC emulation -e.g. QEMU [2], VirtualBox [3], VMWare [4] are able to emulate Intel e1000, Realtek r8169 and other NICs. This is also referred to as full NIC emulation, where the hypervisor implements a NIC hardware model in software, including the transmit and receive memory mapped rings and the Peripheral Component Interconnect (PCI) registers.The paravirtualization approach initially proposed by Xen [5] with the netfront/netback paravitualized NIC, gained popularity over traditional emulation, leading to the advent of VMware vmxnet [6] and the VirtIO [7] standard for I/O paravirtualization. NIC paravirtualization (and I/O paravirtualization in general) is a software technique that greatly improves VM networking performance and eases implementation of VM I/O support in hypervisors. Paravirtualization removes the need to implement the emulation of hardware-related details and features, thereby exposing a simple and efficient interface for shared-memory communication between VM and hypervisor.

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