Network Virtualization in Data Centre Networks Clause Samples

Network Virtualization in Data Centre Networks. Deliverable D1.3 [2], produced in WP1, which reports on existing optical and control plane technologies has analysed a variety of solutions for network virtualization considering both industrial products and open-source software. In both cases, network virtualization strongly relies on the SDN paradigm. A conceptually centralized SDN controller configures the underlying physical network devices and/or the servers at the network edges to create multiple instances of virtualized and isolated networks which share a common physical infrastructure. The network virtualization solutions analysed in WP1 mostly operates on L2-L3 networks, without considering the virtualization of optical technologies. Two main categories of network virtualization have been identified: overlay-based network virtualization and direct fabric programming. The former solution delivers customer-defined infrastructures, often including L4-L7 services and based on the required application-layer connectivity. The multi-tenant overlay networks are implemented encapsulating the traffic at the end-point level, using VXLAN, NVGRE or STT technologies. The traffic generated at the network edges is delivered through virtual tunnels created on top of the physical infrastructure, without requiring any configuration of the internal network devices. Overlay- based virtualization is simple and fast to deploy, since it requires only configuration at the network edges, without any impact on the configuration of the physical connectivity. However, this is also its major limitation, since the decoupling between overlay and physical networks means lack of visibility and, consequently, lack of control on the data plane resources. In other terms, the physical connectivity is used by the virtual tunnels as it is, without any coordinated adaptation to optimize the network performance and usage, to meet specific requirements at the virtual infrastructure level or just to react to data plane failures. On the other hand, underlay-based network virtualization solutions with direct configuration of the network fabric dynamically create network paths programming the virtual or physical devices, for example using the OpenFlow protocol [OF], and maintain more control on the data plane configuration. The current research is focusing on possible mechanisms to efficiently coordinate these two virtualization approaches. This coordination has twofold benefits: on one hand it allows to reconfigure the underlying data plane d...