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 Terminology

A number of terms are used in the provider extension and in the configuration of plugins supporting the provider extension:

  • virtual network - A Quantum L2 network (identified by a UUID and optional name) whose ports can be attached as vNICs to Nova instances and to various Quantum agents. The openvswitch and linuxbridge plugins each support several different mechanisms to realize virtual networks.

  • physical network - A network connecting virtualization hosts (i.e. Nova compute nodes) with each other and with other network resources. Each physical network may support multiple virtual networks. The provider extension and the plugin configurations identify physical networks using simple string names.

  • tenant network - A "normal" virtual network created by/for a tenant. The tenant is not aware of how that network is physically realized.

  • provider network - A virtual network administratively created to map to a specific network in the data center, typically to enable direct access to non-OpenStack resources on that network. Tenants can be given access to provider networks.

  • VLAN network - A virtual network realized as packets on a specific physical network containing IEEE 802.1Q headers with a specific VID field value. VLAN networks sharing the same physical network are isolated from each other at L2, and can even have overlapping IP address spaces. Each distinct physical network supporting VLAN networks is treated as a separate VLAN trunk, with a distinct space of VID values. Valid VID values are 1 through 4094.

  • flat network - A virtual network realized as packets on a specific physical network containing no IEEE 802.1Q header. Each physical network can realize at most one flat network.

  • local network - A virtual network that allows communication within each host, but not across a network. Local networks are intended mainly for single-node test scenarios, but may have other uses.

  • GRE network - A virtual network realized as network packets encapsulated using GRE. GRE networks are also referred to as "tunnels". GRE tunnel packets are routed by the host's IP routing table, so GRE networks are not associated by Quantum with specific physical networks.

Both the openvswitch and linuxbridge plugins support VLAN networks, flat networks, and local networks. Only the openvswitch plugin currently supports GRE networks, provided that the host's Linux kernel supports the required Open vSwitch features.



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