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• Provides detailed visibility into the behavior and performance of all traffic sent in the virtual network
environment.
A vSwitch greatly simplifies IT administration in virtualized networking environments—all VM configuration and
statistics remain bound to the VM even if it migrates from one physical host in the resource pool to another. See
the XenServer vSwitch Controller User Guide for more details.
Note:
To revert to the Linux network stack, run the following command:
xe-switch-network-backend bridge
Reboot your host after running this command.
Warning:
The Linux network stack is not open-flow enabled, does not support Cross Server Private
Networks, and cannot be managed by the XenServer vSwitch Controller.
XenServer Networking Overview
This section describes the general concepts of networking in the XenServer environment.
One network is created for each physical network interface card (NIC) during XenServer installation. When you
add a server to a resource pool, these default networks are merged so that all physical NICs with the same device
name are attached to the same network.
Typically, you would only add a new network if you wanted to create an internal network, set up a new VLAN
using an existing NIC, or create a NIC bond.
You can configure four different types of networks in XenServer:
•Single-Server Private networks have no association to a physical network interface and can be used to provide
connectivity between the virtual machines on a given host, with no connection to the outside world.
•Cross-Server Private networks extend the single server private network concept to allow VMs on different
hosts to communicate with each other by using the vSwitch.
•External networks have an association with a physical network interface and provide a bridge between a virtual
machine and the physical network interface connected to the network, enabling a virtual machine to connect
to resources available through the server's physical network interface card.
•Bonded networks create a bond between two NICs to create a single, high-performing channel between the
virtual machine and the network.
Note:
Some networking options have different behaviors when used with standalone XenServer
hosts compared to resource pools. This chapter contains sections on general information that
applies to both standalone hosts and pools, followed by specific information and procedures
for each.

Network Objects

This chapter uses three types of server-side software objects to represent networking entities. These objects are:
• A PIF, which represents a physical NIC on a XenServer host. PIF objects have a name and description, a globally
unique UUID, the parameters of the NIC that they represent, and the network and server they are connected to.
• A VIF, which represents a virtual NIC on a virtual machine. VIF objects have a name and description, a globally
unique UUID, and the network and VM they are connected to.