Merge "Add Security and Connectivity Implications to DISALLOW_CELLULAR_2G Docs" into udc-qpr-dev

    /**

     * Specifies if a user is not allowed to use 2g networks.

     *

     * <p> This is a security feature. 2g has no mutual authentication between a device and

     * cellular base station and downgrading a device's connection to 2g is a common tactic for

     * several types of privacy and security compromising attacks that could allow an adversary

     * to intercept, inject, or modify cellular communications.

     *

     * <p>This restriction can only be set by a device owner or a profile owner of an

     * organization-owned managed profile on the parent profile.

     * In all cases, the setting applies globally on the device and will prevent the device from

     * scanning for or connecting to 2g networks, except in the case of an emergency.

     * In all cases, the setting applies globally on the device.

     *

     * <p> Cellular connectivity loss (where a device would have otherwise successfully

     * connected to a 2g network) occurs if the device is in an area where only 2g networks are

     * available. Emergency calls are an exception and are never impacted. The device will still

     * scan for and connect to a 2g network for emergency calls.

     *

     * <p>Holders of the permission

     * {@link android.Manifest.permission#MANAGE_DEVICE_POLICY_MOBILE_NETWORK}