@@ -283,16 +283,22 @@ It also includes the following parts if they are sold with the interface:
* Removable/changable antenna
* Daughter boards/add-on hardware modules
A virtual network interface consists of a device driver only.
### 4.3.2 Types of network interface
A physical network interface connects via its communications bus to the host. The host transmits and receives data to the network by means of the I/O interface provided by the network interface.
A wired network interface transmits data via a solid transmission media such as Ethernet cable, fiber optic cable, or coaxial cable. A wireless network interface uses radiofrequency transmissions to transmit data. A virtual network interface transmits data within the memory of a host system.
Wireless network interfaces often have an independent real-time operating system on the network interface itself. Wireless transmission media often requires real-time response to modulate the radio frequency transmissions properly. The network interface also must prevent improper settings of radio frequency transmission parameters, which is often implemented by having the internal firmware set the parameters, rather than exposing them to the host. The complexity of this firmware may increase the risk of a wireless interface.
A virtual interface emulates the device driver interface of a network interface to the host operating system. Instead of a physical network interface, it may send and receive packets to a hypervisor, a container, another device driver, another part of the network stack, an application, or other software.
A device driver is software running on the host that facilitates the transmission of network data. The device driver communicates with the host software, if any, by means of a network device driver interface. This interface abstracts the implementation details of the underlying network interface. This network device driver interface is typically defined by the host operating system and is used by its network stack to send or receive data through any device driver that supports this interface.
@@ -301,7 +307,7 @@ Physical interfaces require device drivers to make use of the physical hardware.
The device driver often needs elevated privileges to read and write memory. Device drivers for physical network interfaces often must also have access to address space mapped to the network interface's control registers, and sometimes to enable or disable interrupts or other host hardware functions. This usually requires that the device driver have a high degree of privilege on the host system.
