7.4. Data Connectivity

7.4.1. Telephony

“Telephony” as used by the Android APIs and this document refers specifically to hardware related to placing voice calls and sending SMS messages via a GSM or CDMA network. While these voice calls may or may not be packet-switched, they are for the purposes of Android considered independent of any data connectivity that may be implemented using the same network. In other words, the Android “telephony” functionality and APIs refer specifically to voice calls and SMS. For instance, device implementations that cannot place calls or send/receive SMS messages MUST NOT report the android.hardware.telephony feature or any subfeatures, regardless of whether they use a cellular network for data connectivity.

Android MAY be used on devices that do not include telephony hardware. That is, Android is compatible with devices that are not phones. However, if a device implementation does include GSM or CDMA telephony, it MUST implement full support for the API for that technology. Device implementations that do not include telephony hardware MUST implement the full APIs as no-ops.

7.4.1.1. Number Blocking Compatibility

Android Telephony device implementations MUST include number blocking support and:

• MUST fully implement BlockedNumberContract and the corresponding API as described in the SDK documentation.
• MUST block all calls and messages from a phone number in ‘BlockedNumberProvider’ without any interaction with apps. The only exception is when number blocking is temporarily lifted as described in the SDK documentation.
• MUST NOT write to the platform call log provider for a blocked call.
• MUST NOT write to the Telephony provider for a blocked message.
• MUST implement a blocked numbers management UI, which is opened with the intent returned by TelecomManager.createManageBlockedNumbersIntent() method.
• MUST NOT allow secondary users to view or edit the blocked numbers on the device as the Android platform assumes the primary user to have full control of the telephony services, a single instance, on the device. All blocking related UI MUST be hidden for secondary users and the blocked list MUST still be respected.
• SHOULD migrate the blocked numbers into the provider when a device updates to Android 7.0.

7.4.2. IEEE 802.11 (Wi-Fi)

All Android device implementations SHOULD include support for one or more forms of 802.11. If a device implementation does include support for 802.11 and exposes the functionality to a third-party application, it MUST implement the corresponding Android API and:

• MUST report the hardware feature flag android.hardware.wifi.
• MUST implement the multicast API as described in the SDK documentation.
• MUST support multicast DNS (mDNS) and MUST NOT filter mDNS packets (224.0.0.251) at any time of operation including:
  • Even when the screen is not in an active state.
  • For Android Television device implementations, even when in standby power states.

7.4.2.1. Wi-Fi Direct

Device implementations SHOULD include support for Wi-Fi Direct (Wi-Fi peer-to-peer). If a device implementation does include support for Wi-Fi Direct, it MUST implement the corresponding Android API as described in the SDK documentation. If a device implementation includes support for Wi-Fi Direct, then it:

• MUST report the hardware feature android.hardware.wifi.direct.
• MUST support regular Wi-Fi operation.
• SHOULD support concurrent Wi-Fi and Wi-Fi Direct operation.

7.4.2.2. Wi-Fi Tunneled Direct Link Setup

Device implementations SHOULD include support for Wi-Fi Tunneled Direct Link Setup (TDLS) as described in the Android SDK Documentation. If a device implementation does include support for TDLS and TDLS is enabled by the WiFiManager API, the device:

• SHOULD use TDLS only when it is possible AND beneficial.
• SHOULD have some heuristic and NOT use TDLS when its performance might be worse than going through the Wi-Fi access point.

7.4.3. Bluetooth

Android Watch implementations MUST support Bluetooth. Android Television implementations MUST support Bluetooth and Bluetooth LE. Android Automotive implementations MUST support Bluetooth and SHOULD support Bluetooth LE.

Device implementations that support android.hardware.vr.high_performance feature MUST support Bluetooth 4.2 and Bluetooth LE Data Length Extension.

Android includes support for Bluetooth and Bluetooth Low Energy. Device implementations that include support for Bluetooth and Bluetooth Low Energy MUST declare the relevant platform features (android.hardware.bluetooth and android.hardware.bluetooth_le respectively) and implement the platform APIs. Device implementations SHOULD implement relevant Bluetooth profiles such as A2DP, AVCP, OBEX, etc. as appropriate for the device.

Android Automotive implementations SHOULD support Message Access Profile (MAP). Android Automotive implementations MUST support the following Bluetooth profiles:

• Phone calling over Hands-Free Profile (HFP).
• Media playback over Audio Distribution Profile (A2DP).
• Media playback control over Remote Control Profile (AVRCP).
• Contact sharing using the Phone Book Access Profile (PBAP).

Device implementations including support for Bluetooth Low Energy:

• MUST declare the hardware feature android.hardware.bluetooth_le.
• MUST enable the GATT (generic attribute profile) based Bluetooth APIs as described in the SDK documentation and android.bluetooth.
• are STRONGLY RECOMMENDED to implement a Resolvable Private Address (RPA) timeout no longer than 15 minutes and rotate the address at timeout to protect user privacy.
• SHOULD support offloading of the filtering logic to the bluetooth chipset when implementing the ScanFilter API, and MUST report the correct value of where the filtering logic is implemented whenever queried via the android.bluetooth.BluetoothAdapter.isOffloadedFilteringSupported() method.
• SHOULD support offloading of the batched scanning to the bluetooth chipset, but if not supported, MUST report ‘false’ whenever queried via the android.bluetooth.BluetoothAdapter.isOffloadedScanBatchingSupported() method.
• SHOULD support multi advertisement with at least 4 slots, but if not supported, MUST report ‘false’ whenever queried via the android.bluetooth.BluetoothAdapter.isMultipleAdvertisementSupported() method.

7.4.4. Near-Field Communications

Device implementations SHOULD include a transceiver and related hardware for Near-Field Communications (NFC). If a device implementation does include NFC hardware and plans to make it available to third-party apps, then it:

• MUST report the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method.
• MUST be capable of reading and writing NDEF messages via the following NFC standards:
  • MUST be capable of acting as an NFC Forum reader/writer (as defined by the NFC Forum technical specification NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards:
    • NfcA (ISO14443-3A)
    • NfcB (ISO14443-3B)
    • NfcF (JIS X 6319-4)
    • IsoDep (ISO 14443-4)
    • NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)
  • STRONGLY RECOMMENDED to be capable of reading and writing NDEF messages as well as raw data via the following NFC standards. Note that while the NFC standards below are stated as STRONGLY RECOMMENDED, the Compatibility Definition for a future version is planned to change these to MUST. These standards are optional in this version but will be required in future versions. Existing and new devices that run this version of Android are very strongly encouraged to meet these requirements now so they will be able to upgrade to the future platform releases.
    • NfcV (ISO 15693)
  • SHOULD be capable of reading the barcode and URL (if encoded) of Thinfilm NFC Barcode products.
  • MUST be capable of transmitting and receiving data via the following peer-to-peer standards and protocols:
    • ISO 18092
    • LLCP 1.2 (defined by the NFC Forum)
    • SDP 1.0 (defined by the NFC Forum)
    • NDEF Push Protocol
    • SNEP 1.0 (defined by the NFC Forum)
  • MUST include support for Android Beam.
  • MUST implement the SNEP default server. Valid NDEF messages received by the default SNEP server MUST be dispatched to applications using the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam in settings MUST NOT disable dispatch of incoming NDEF message.
  • MUST honor the android.settings.NFCSHARING_SETTINGS intent to show NFC sharing settings.
  • MUST implement the NPP server. Messages received by the NPP server MUST be processed the same way as the SNEP default server.
  • MUST implement a SNEP client and attempt to send outbound P2P NDEF to the default SNEP server when Android Beam is enabled. If no default SNEP server is found then the client MUST attempt to send to an NPP server.
  • MUST allow foreground activities to set the outbound P2P NDEF message using android.nfc.NfcAdapter.setNdefPushMessage, and android.nfc.NfcAdapter.setNdefPushMessageCallback, and android.nfc.NfcAdapter.enableForegroundNdefPush.
  • SHOULD use a gesture or on-screen confirmation, such as ‘Touch to Beam’, before sending outbound P2P NDEF messages.
  • SHOULD enable Android Beam by default and MUST be able to send and receive using Android Beam, even when another proprietary NFC P2p mode is turned on.
  • MUST support NFC Connection handover to Bluetooth when the device supports Bluetooth Object Push Profile. Device implementations MUST support connection handover to Bluetooth when using android.nfc.NfcAdapter.setBeamPushUris, by implementing the “Connection Handover version 1.2” and “Bluetooth Secure Simple Pairing Using NFC version 1.0” specs from the NFC Forum. Such an implementation MUST implement the handover LLCP service with service name “urn:nfc:sn:handover” for exchanging the handover request/select records over NFC, and it MUST use the Bluetooth Object Push Profile for the actual Bluetooth data transfer. For legacy reasons (to remain compatible with Android 4.1 devices), the implementation SHOULD still accept SNEP GET requests for exchanging the handover request/select records over NFC. However an implementation itself SHOULD NOT send SNEP GET requests for performing connection handover.
  • MUST poll for all supported technologies while in NFC discovery mode.
  • SHOULD be in NFC discovery mode while the device is awake with the screen active and the lock-screen unlocked.

(Note that publicly available links are not available for the JIS, ISO, and NFC Forum specifications cited above.)

Android includes support for NFC Host Card Emulation (HCE) mode. If a device implementation does include an NFC controller chipset capable of HCE (for NfcA and/or NfcB) and it supports Application ID (AID) routing, then it:

• MUST report the android.hardware.nfc.hce feature constant.
• MUST support NFC HCE APIs as defined in the Android SDK.

If a device implementation does include an NFC controller chipset capable of HCE for NfcF, and it implements the feature for third-party applications, then it:

• MUST report the android.hardware.nfc.hcef feature constant.
• MUST implement the [NfcF Card Emulation APIs] (https://developer.android.com/reference/android/nfc/cardemulation/NfcFCardEmulation.html) as defined in the Android SDK.

Additionally, device implementations MAY include reader/writer support for the following MIFARE technologies.

• MIFARE Classic
• MIFARE Ultralight
• NDEF on MIFARE Classic

Note that Android includes APIs for these MIFARE types. If a device implementation supports MIFARE in the reader/writer role, it:

• MUST implement the corresponding Android APIs as documented by the Android SDK.
• MUST report the feature com.nxp.mifare from the android.content.pm.PackageManager.hasSystemFeature() method. Note that this is not a standard Android feature and as such does not appear as a constant in the android.content.pm.PackageManager class.
• MUST NOT implement the corresponding Android APIs nor report the com.nxp.mifare feature unless it also implements general NFC support as described in this section.

If a device implementation does not include NFC hardware, it MUST NOT declare the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method, and MUST implement the Android NFC API as a no-op.

As the classes android.nfc.NdefMessage and android.nfc.NdefRecord represent a protocol-independent data representation format, device implementations MUST implement these APIs even if they do not include support for NFC or declare the android.hardware.nfc feature.

7.4.5. Minimum Network Capability

Device implementations MUST include support for one or more forms of data networking. Specifically, device implementations MUST include support for at least one data standard capable of 200Kbit/sec or greater. Examples of technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, Ethernet, Bluetooth PAN, etc.

Device implementations where a physical networking standard (such as Ethernet) is the primary data connection SHOULD also include support for at least one common wireless data standard, such as 802.11 (Wi-Fi).

Devices MAY implement more than one form of data connectivity.

Devices MUST include an IPv6 networking stack and support IPv6 communication using the managed APIs, such as java.net.Socket and java.net.URLConnection, as well as the native APIs, such as AF_INET6 sockets. The required level of IPv6 support depends on the network type, as follows:

• Devices that support Wi-Fi networks MUST support dual-stack and IPv6-only operation on Wi-Fi.
• Devices that support Ethernet networks MUST support dual-stack operation on Ethernet.
• Devices that support cellular data SHOULD support IPv6 operation (IPv6-only and possibly dual-stack) on cellular data.
• When a device is simultaneously connected to more than one network (e.g., Wi-Fi and cellular data), it MUST simultaneously meet these requirements on each network to which it is connected.

IPv6 MUST be enabled by default.

In order to ensure that IPv6 communication is as reliable as IPv4, unicast IPv6 packets sent to the device MUST NOT be dropped, even when the screen is not in an active state. Redundant multicast IPv6 packets, such as repeated identical Router Advertisements, MAY be rate-limited in hardware or firmware if doing so is necessary to save power. In such cases, rate-limiting MUST NOT cause the device to lose IPv6 connectivity on any IPv6-compliant network that uses RA lifetimes of at least 180 seconds.

IPv6 connectivity MUST be maintained in doze mode.

7.4.6. Sync Settings

Device implementations MUST have the master auto-sync setting on by default so that the method getMasterSyncAutomatically() returns “true”.

7.4.7. Data Saver

Device implementations with a metered connection are STRONGLY RECOMMENDED to provide the data saver mode.

If a device implementation provides the data saver mode, it:

• MUST support all the APIs in the ConnectivityManager class as described in the SDK documentation

• MUST provide a user interface in the settings, allowing users to add applications to or remove applications from the whitelist.

Conversely if a device implementation does not provide the data saver mode, it:

• MUST return the value RESTRICT_BACKGROUND_STATUS_DISABLED for ConnectivityManager.getRestrictBackgroundStatus()

• MUST not broadcast ConnectivityManager.ACTION_RESTRICT_BACKGROUND_CHANGED

• MUST have an activity that handles the Settings.ACTION_IGNORE_BACKGROUND_DATA_RESTRICTIONS_SETTINGS intent but MAY implement it as a no-op.