ovs

Open vSwitch (OVS) is an open-source, multilayer virtual switch designed to enable network automation in virtualized server environments. It is deployed in cloud, virtualization, and NFV setups to provide virtual switching, network segmentation, and programmable networking.

OVS consists of a kernel datapath (in Linux) for high-performance forwarding and a user-space control stack. The main daemons are ovs-vswitchd, which implements the switch logic, and ovsdb-server, which stores configuration in the OVS Database (OVSDB). Clients such as ovs-vsctl and ovs-appctl manage and query the system. OVS supports OpenFlow for centralized control, but it can also run in a non-OpenFlow, policy-based mode.

Key features include bridging, VLAN tagging, and support for various tunneling protocols to build overlay networks, such as VXLAN, GRE, and Geneve. It provides port-level QoS, ACLs, and bonding, along with integration with external controllers and orchestration platforms.

OVS has native support for Linux networking and integrates with virtualization platforms like KVM, Xen, and Hyper-V, as well as cloud stacks such as OpenStack and Kubernetes (via CNI or OVN). It also supports multiple datapaths, including a kernel datapath for performance and a userspace datapath for flexibility.

Open vSwitch is released as open-source software under the Apache License 2.0 and is maintained by a global community of contributors. It is widely used to implement virtual networks, manage network policies, and provide programmable networking in modern data centers.