Choosing a networking plugin
Neutron networking plugins are responsible for implementing features that provide network connectivity to and from instances. The two plugins discussed in this book, LinuxBridge and Open vSwitch, implement those features in different ways.
LinuxBridge
When configured to utilize the LinuxBridge networking plugin, Neutron relies on the bridge and 8021q kernel modules to properly connect instances and other network resources to the virtual switch and forward traffic.
In a LinuxBridge-based network implementation, there are three distinct types of virtual networking devices:
- Tap devices
- VLAN interfaces
- Linux bridges
A tap device is how a hypervisor such as KVM implements a virtual network interface card. These virtual interfaces on the host correspond to an interface inside the guest instance. An Ethernet frame sent to the tap device is received by the guest operating system.
Linux supports 802.1q VLAN tagging through the use of virtual VLAN interfaces. The kernel can...
