Fix network heading levels

Adjust network socket and interfaces heading levels, so TOC makes sense.

Author: AnotherButler

docs/api/light-control.md

@@ -1,8 +1,8 @@
-<h1 id="light-control">Light control tutorial</h1>
+<h2 id="light-control">Light control tutorial</h2>
 
 The application below demonstrates a simple light control application, where devices can control the LED status of all devices in the network. You can build the application for the unsecure 6LoWPAN-ND or Thread network.
 
-## Download the application
+### Download the application
 
 ```
 mbed import mbed-os-example-mesh-minimal
@@ -13,11 +13,11 @@ Or click `Import into Mbed IDE` in the example below:
 
 [![View code](https://www.mbed.com/embed/?url=https://github.com/ARMmbed/mbed-os-example-mesh-minimal)](https://github.com/ARMmbed/mbed-os-example-mesh-minimal/blob/mbed-os-5.14/mesh_led_control_example.cpp)
 
-## Change the channel settings (optional)
+### Change the channel settings (optional)
 
 See the file `mbed_app.json` for an example of defining an IEEE 802.15.4 channel to use.
 
-## Selecting optimal Nanostack configuration
+### Selecting optimal Nanostack configuration
 
 To optimize the flash usage, select a proper configuration for Nanostack. The configuration depends mostly on the preferred use case.
 
@@ -68,7 +68,7 @@ The following tables show the values to use in the `mbed_app.json` file for your
 - For a 6LoWPAN-ND based network, use `nsapi.default-mesh-type: LOWPAN`.
 - For a Thread-based network, use `nsapi.default-mesh-type: THREAD`.
 
-### 6LoWPAN-ND
+#### 6LoWPAN-ND
 
 **nsapi.default-mesh-type: LOWPAN**
 
@@ -77,7 +77,7 @@ The following tables show the values to use in the `mbed_app.json` file for your
 |Mesh router (default) | lowpan_router | NET_6LOWPAN_ROUTER |
 |Nonrouting device | lowpan_host | NET_6LOWPAN_HOST |
 
-### Thread
+#### Thread
 
 **nsapi.default-mesh-type: THREAD**
 
@@ -86,7 +86,7 @@ The following tables show the values to use in the `mbed_app.json` file for your
 |Mesh router (default) | thread_router | MESH_DEVICE_TYPE_THREAD_ROUTER |
 |Nonrouting device | thread_end_device | MESH_DEVICE_TYPE_THREAD_SLEEPY_END_DEVICE |
 
-#### Thread commissioning
+##### Thread commissioning
 
 By default, the Thread application uses the static network link configuration defined in the [mesh API configuration file](https://github.com/ARMmbed/mbed-os/blob/master/features/nanostack/mbed-mesh-api/mbed_lib.json).
 If you want to commission a Thread device, see [how to commission a Thread device in practice](../reference/thread-tech.html#thread-commissioning).
@@ -100,7 +100,7 @@ The Thread stack learns the network settings from the commissioning process and
 - Commission the device to the Thread network.
 - When you restart the device next time, the device reads the Thread configuration settings from the SD card and tries to attach to an existing network.
 
-## Requirements for hardware
+### Requirements for hardware
 
 The networking stack in this example requires TLS functionality to be enabled on Mbed TLS. On devices where hardware entropy is not present, TLS is disabled by default. This results in compile time failures or linking failures.
 
@@ -110,7 +110,7 @@ See [Notes on different hardware](https://github.com/ARMmbed/mbed-os-example-mes
 
 You also need to check how LEDs and buttons are configured for your hardware, and update the `.json` file accordingly.
 
-## Changing the radio driver
+### Changing the radio driver
 
 To run a 6LoWPAN-ND network, you need a working RF driver for Nanostack. This example uses the Atmel AT86RF233 by default.
 
@@ -121,23 +121,23 @@ To change the RF driver, modify the `mbed_app.json` file by setting preferred RF
 "mcr20a.provide-default": true
 ```
 
-## Compile the application
+### Compile the application
 
 ```
 mbed compile -m K64F -t GCC_ARM
 ```
 
 A binary is generated in the end of the build process.
 
-## Connect the RF shield to the board
+### Connect the RF shield to the board
 
 This example uses the Atmel AT86RF233, which you can [purchase](https://firefly-iot.com/product/firefly-arduino-shield-2-4ghz/). Place the shield on top of your board, and power it on.
 
-## Program the target
+### Program the target
 
 Drag and drop the binary to the target to program the application.
 
-## Update the firmware of the border router
+### Update the firmware of the border router
 
 This example supports the following border router:
 
@@ -147,7 +147,7 @@ The border router supports static and dynamic backhaul configuration. The static
 
 Remember to connect the Ethernet cable between the border router and your router. Then power on the board.
 
-## Testing
+### Testing
 
 By default, the application is built for the LED control demo, in which the device sends a multicast message to all devices in the network when the button is pressed. All devices that receive the multicast message will change the LED status (red LED on/off) to the state defined in the message. Note that the Thread devices can form a network without the existence of the border router. The following applies only to the case when the border router is set up.
 
@@ -161,31 +161,31 @@ connected. IP = 2001:db8:a0b:12f0::1
 
 You can use this IP address to `ping` from your PC and verify that the connection is working correctly.
 
-## Memory optimizations
+### Memory optimizations
 
 On some limited platforms, for example NCS36510 or KW24D, building this application might run out of RAM or ROM. In those cases, you can try these instructions to optimize the memory use.
 
-### Mbed TLS configuration
+#### Mbed TLS configuration
 
 You can set the custom Mbed TLS configuration by adding `"macros": ["MBEDTLS_USER_CONFIG_FILE=\"mbedtls_config.h\""]` to the `.json` file. The [example Mbed TLS configuration](https://github.com/ARMmbed/mbed-os-example-mesh-minimal/blob/master/mbedtls_config.h) minimizes the RAM and ROM use of the application. The is not guaranteed to work on every Mbed Enabled platform.
 
 This configuration file saves you 8.7 kB of RAM but uses 6.8 kB of more flash.
 
-### Disabling the LED control example
+#### Disabling the LED control example
 
 You can disable the LED control example by specifying `enable-led-control-example": false` in `mbed_app.json`.
 
 This saves you about 2.5 kB of flash.
 
-### Change network stack's event loop stack size
+#### Change network stack's event loop stack size
 
 Nanostack's internal event loop is shared with Mbed Client and therefore requires lots of stack to complete the security handshakes using TLS protocols. If you're not using client functionality, you can define the following to use 2 kB of stack:
 
 `"nanostack-hal.event_loop_thread_stack_size": 2048`
 
 This saves you 4 kB of RAM.
 
-### Change Nanostack's heap size
+#### Change Nanostack's heap size
 
 Nanostack uses internal heap, which you can configure in the `.json`. A thread end device with commissioning enabled requires at least 15 kB to run.
 
@@ -197,7 +197,7 @@ In `mbed_app.json`, you find the following line:
 
 For 6LoWPAN, you can try 12 kB. For the smallest memory use, configure the node to be in nonrouting mode. See [module-configuration](https://github.com/ARMmbed/mbed-os/tree/master/features/nanostack/FEATURE_NANOSTACK/mbed-mesh-api#module-configuration) for more detail.
 
-### Move Nanostack's heap inside the system heap
+#### Move Nanostack's heap inside the system heap
 
 You can move Nanostack's internal heap within the system heap. This helps on devices with split RAM and on devices in which the compiler fails to fit statically allocated symbols into one section, for example, the NXP KW24D device.
 
@@ -209,7 +209,7 @@ Add the following line to `mbed_app.json` to test:
 "mbed-mesh-api.use-malloc-for-heap": true
 ```
 
-### Use release profile
+#### Use release profile
 
 For devices with small memory, we recommend using release profiles for building and exporting. Please see the documentation about [build profiles](../tools/build-profiles.html).
 
@@ -221,6 +221,6 @@ OR
 $ mbed compile -m KW24D -t IAR --profile release
 ```
 
-## Troubleshooting
+### Troubleshooting
 
 If you have problems, you can review the [documentation](../tutorials/debugging.html) for suggestions on what could be wrong and how to fix it.

docs/api/networkinterfaces/CellularInterface.md

@@ -1,4 +1,4 @@
-<h1 id="cellular-api">Cellular API</h1>
+<h2 id="cellular-api">Cellular API</h2>
 
 <span class="images">![](https://os.mbed.com/docs/development/mbed-os-api-doxy/class_cellular_interface.png)<span>CellularInterface class hierarchy</span></span>
 
@@ -7,7 +7,7 @@
 
 The [CellularInterface](../mbed-os-api-doxy/class_cellular_interface.html) class provides a C++ API for connecting to the internet over a Cellular device.
 
-## Getting started
+### Getting started
 
 1. Choose an [Mbed board that supports cellular](https://os.mbed.com/platforms/?mbed-enabled=15&connectivity=1), such as the [UBLOX-C027](https://os.mbed.com/platforms/u-blox-C027/) or [MTS-DRAGONFLY](https://os.mbed.com/platforms/MTS-Dragonfly/).
 
@@ -31,7 +31,7 @@ Received from echo server 4 Bytes
 Success. Exiting
 ```
 
-## Basic working principles
+### Basic working principles
 
 You can use and extend a cellular interface in various different ways. For example,
 
@@ -49,25 +49,25 @@ You can use and extend a cellular interface in various different ways. For examp
 - The easy cellular connection uses standard 3GPP AT 27.007 AT commands to set up the cellular modem and to register to the network.
 - After registration, the driver opens a PPP pipe using LWIP with the cellular modem and connects to the internet. If AT only mode is in use, then modem-specific AT commands are used for socket data control.
 
-## CellularInterface class reference
+### CellularInterface class reference
 
 [![View code](https://www.mbed.com/embed/?type=library)](https://os.mbed.com/docs/development/mbed-os-api-doxy/class_cellular_interface.html)
 
-## Usage
+### Usage
 
 To bring up the network interface:
 
 1. Instantiate an implementation of the CellularInterface class.
 1. Call the `connect(pincode, apn)` function with a PIN code for your SIM card and an APN for your network.
 1. Once connected, you can use Mbed OS [network sockets](network-socket.html) as usual.
 
-## Cellular example: connection establishment
+### Cellular example: connection establishment
 
 This example establishes connection with the cellular network using Mbed OS CellularInterface.
 
 [![View code](https://www.mbed.com/embed/?url=https://github.com/ARMmbed/mbed-os-example-cellular)](https://github.com/ARMmbed/mbed-os-example-cellular/blob/mbed-os-5.14/main.cpp)
 
-## Related content
+### Related content
 
 - [Network socket](network-socket.html) API reference overview.
 - [Cellular overview](../reference/cellular-networking.html) describes cellular architecture and its usage in more detail.

docs/api/networkinterfaces/EthInterface.md

@@ -2,9 +2,7 @@
 
 <span class="images">![](https://os.mbed.com/docs/development/mbed-os-api-doxy/class_eth_interface.png)<span>EthInterface class hierarchy</span></span>
 
-The `EthInterface` provides a C++ API for connecting to the internet over Ethernet.
-By default, this class does not require any configuration. It is able to pick up the default
-Ethernet driver for the target and select correct network stack.
+The `EthInterface` provides a C++ API for connecting to the internet over Ethernet. By default, this class does not require any configuration. It is able to pick up the default Ethernet driver for the target and select correct network stack.
 
 
 ## Usage

docs/api/networkinterfaces/MeshInterface.md

@@ -1,8 +1,8 @@
-<h1 id="mesh-api">Mesh</h1>
+<h2 id="mesh-api">Mesh</h2>
 
 <span class="images">![](https://os.mbed.com/docs/development/mbed-os-api-doxy/class_mesh_interface.png)<span>MeshInterface class hierarchy</span></span>
 
-The Arm Mbed Mesh API allows the application to use the IPv6 mesh network topologies through the [Nanostack](../reference/6LoWPAN-ND-tech.html) networking stack. 
+The Arm Mbed Mesh API allows the application to use the IPv6 mesh network topologies through the [Nanostack](../reference/6LoWPAN-ND-tech.html) networking stack.
 
 Mbed OS provides three types of IPv6-based mesh networks:
 
@@ -14,11 +14,11 @@ The application can use the `LoWPANNDInterface`, `WisunInterface` or `ThreadInte
 
 You can configure the mesh interface by providing values in `mbed_app.json`, as the [mesh configuration](../reference/configuration-mesh.html) section documents.
 
-## Mesh class reference
+### Mesh class reference
 
 [![View code](https://www.mbed.com/embed/?type=library)](https://os.mbed.com/docs/development/mbed-os-api-doxy/class_mesh_interface.html)
 
-## Mesh example
+### Mesh example
 
 The following code snippet illustrates how you can use the MeshInterface API:
 
@@ -48,7 +48,7 @@ int main(void)
 
 ```
 
-## Related content
+### Related content
 
 - [Mesh tutorial](../tutorials/mesh-tutorial.html) to start using mesh technology.
 - [Light control tutorial](../tutorials/light-control.html), in which devices can control the LED status of all devices in the network.

docs/api/networkinterfaces/NetworkStatus.md

@@ -1,10 +1,10 @@
-<h1 id="network-status">Network status</h1>
+<h2 id="network-status">Network status</h2>
 
 This interface informs you about connection state changes asynchronously. Providing a method to register a callback function to a socket accomplishes this. Each time the network interface's state changes, it triggers the callback.
 
 ![Network states](../../images/NetworkinterfaceStates.png)
 
-## Usage
+### Usage
 
 The callback needs to handle these possible network states:
 
@@ -74,7 +74,7 @@ Optionally, the application might want to set the `connect()` method to nonblock
 
 By default, the `connect()` call blocks until `NSAPI_STATUS_GLOBAL_UP` state is reached. Some applications might require only link-local connectivity and therefore do not need to block that long. In those case monitoring the state changes is the preferred behavior.
 
-## Using multiple connection status callbacks
+### Using multiple connection status callbacks
 
 The NetworkInterface API includes two functions that the applications can use to register more than one status callback for each network interface:
 
@@ -109,12 +109,12 @@ You must either refactor the application by replacing `NetworkInterface::attach(
 
 This optional and has a small RAM and ROM increase, so applications are not required to use it. Both APIs are still supported, but use is limited to one at a time.
 
-## Example
+### Example
 
 Registering a status callback that connection state changes trigger depends on whether the network interface provides this functionality.
 
 [![View code](https://www.mbed.com/embed/?url=https://os.mbed.com/teams/mbed_example/code/TCPSocket_ConnStateCb_Example/)](https://os.mbed.com/teams/mbed_example/code/TCPSocket_ConnStateCb_Example/file/c66df92cf71b/main.cpp)
 
-## Related content
+### Related content
 
 - [Network socket](network-socket.html) API reference overview.

docs/api/networkinterfaces/WifiInterface.md

@@ -1,14 +1,14 @@
-# Wi-Fi
+## Wi-Fi
 
 <span class="images">![](http://os.mbed.com/docs/development/mbed-os-api-doxy/class_wi_fi_interface.png)<span>WiFiInterface class hierarchy</span></span>
 
 The WifiInterface provides a simple C++ API for connecting to the internet over a Wi-Fi device.
 
-## Wi-Fi class reference
+### Wi-Fi class reference
 
 [![View code](https://www.mbed.com/embed/?type=library)](http://os.mbed.com/docs/development/mbed-os-api-doxy/class_wi_fi_interface.html)
 
-## Usage
+### Usage
 
 To bring up the network interface of an external Wi-Fi device (for example, the ESP8266Interface):
 
@@ -28,7 +28,7 @@ To bring up the network interface of an Ethernet-like driver (for example, the O
     2. Ensure the network stack acquires the IP address and DNS server address.
 1. Once connected, you can use the WiFiInterface as a target for opening [network sockets](network-socket.html).
 
-## Troubleshooting information
+### Troubleshooting information
 
 Network interface `connect()` and `set_credential()` might return following errors:
 
@@ -40,7 +40,7 @@ Network interface `connect()` and `set_credential()` might return following erro
 | `NSAPI_ERROR_AUTH_FAILURE` | Wrong password given. |
 | `NSAPI_ERROR_DEVICE_ERROR` | Unknown failure happened in the device. The device may not be capable of reporting more descriptive error codes. |
 
-## Security
+### Security
 
 For specifying security settings, both `connect()` and `set_credential()` have optional parameter `nsapi_security_t security`, which defines the security mode the device uses. WifiInterface supports the following security modes:
 
@@ -54,15 +54,15 @@ For specifying security settings, both `connect()` and `set_credential()` have o
 
 Please note that settings should match the security mode from the access point. Also, not all drivers support every mode. For most compatible settings, use `NSAPI_SECURITY_WPA_WPA2`, and set the Wi-Fi access point to allow only WPA2 mode.
 
-## Wi-Fi example
+### Wi-Fi example
 
 This program scans for Wi-Fi access points in the area. There are multiple [Wi-Fi components](https://os.mbed.com/components/cat/wifi/) that implement the WiFiInterface class. The example below uses the [ESP8266Interface](https://github.com/armmbed/esp8266-driver) and [OdinWiFiInterface](https://github.com/u-blox/ublox-odin-w2-drivers-docs-mbed-5).
 
 The ESP8266Interface uses AT commands over serial interface to connect to an external Wi-Fi device. The OdinWiFiInterface provides an Ethernet-like driver to the Mbed OS network stack. The network stack uses the driver to connect to Wi-Fi:
 
 [![View code](https://www.mbed.com/embed/?url=https://github.com/ARMmbed/mbed-os-example-wifi)](https://github.com/ARMmbed/mbed-os-example-wifi/blob/mbed-os-5.14/main.cpp)
 
-## Related content
+### Related content
 
 - [Wi-Fi components](https://os.mbed.com/components/cat/wifi/).
 - [Network socket](network-socket.html) API overview.