Update Clause 4.1 Product functions to revised structure (was 4.2)

\"Modem interfaces\" are included in the present document. \"Standalone modems\" are excluded from the present document, but may be found in the vertical CRA standard for Routers Modems & Switches [i.9]

## 4.2 Product functions

## 4.1 Product Functions

### 4.2.1 Physical network interface product functions

<mark>Editor’s Note: Product functions should be clearly defined and granular enough to inform decision-making regarding capability-based applicability of related security controls. The recommended structure for doing this is a hierarchical functional decomposition, wherein each larger functional capability is broken down into its constituent parts. This enables manufacturers to easily derive whether their product supports parts of or all of a specific function.</mark>

<mark>Editor’s Note: If the product category consists of multiple distinct product types, the functions of each product type should be listed separately, possibly following an overall function list up with a mapping to product types.</mark>

<mark>Editor’s Note: Where a product contributes to the delivery of services as part of a system, these services do not constitute functionalities of the product. Identify the product’s role in the delivery of services.</mark>

<mark>Editor’s Note: Configuration functionality is equally in scope.</mark>

### 4.1.1 Physical network interface product functions

A physical network interface is the link between the physical transmission media and the host system. The product's essential function is to transfer data between the network and the host.

The product may be able to take actions that affect the entire host system, such as power cycling or reading any part of memory.

### 4.2.2 Device driver product functions

### 4.1.2 Device driver product functions

A device driver manages the network interface on behalf of the host system, often presenting a standardized network device driver interface to the host operating system. It manages the transfer of data from the network interface to and from host memory. It carries out requests by the host software, such as configuration or loading firmware. It may keep and report statistics about network traffic.

### 4.2.3 Virtual network interface product functions

### 4.1.3 Virtual network interface product functions

A virtual network interface presents a network device driver interface to the rest of the host software. It may encrypt, filter, transform, route, discard, or otherwise modify network traffic entering the interface. The network traffic may then be directed to another virtual network interface on the same host, to another executable on the host, or to a physical network interface.