Updated ethernet and wifi interface description

Author: Mika Leppänen

docs/reference/api/connectivity/networksocket/EthInterface.md

@@ -42,6 +42,12 @@ For EthernetInterface, there are two possible configurations:
 
 Refer to the API below for how to set the IP addresses by calling the `set_network()` function.
 
+### Troubleshooting information
+
+Network interface `connect` failure causes:
+1. `NSAPI_ERROR_NO_CONNECTION` indicates that Ethernet link up has failed. Check that the Ethernet connection is working.
+1. `NSAPI_ERROR_DHCP_FAILURE` indicates that acquiring IP address has failed. Check that the IP address configuration service is working.
+
 ### EthInterface class reference
 
 [![View code](https://www.mbed.com/embed/?type=library)](http://os-doc-builder.test.mbed.com/docs/development/mbed-os-api-doxy/class_eth_interface.html)

docs/reference/api/connectivity/networksocket/WifiInterface.md

@@ -4,20 +4,42 @@
 
 The WifiInterface provides a simple C++ API for connecting to the internet over a Wi-Fi device.
 
-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).
+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). 
+
+ESP8266Interface uses AT commands over serial interface to connect to external Wi-Fi device. OdinWiFiInterface provides Ethernet like driver to Mbed OS network stack. Network stack uses the driver to connect to Wi-Fi.
 
 ### Wi-Fi class reference
 
 [![View code](https://www.mbed.com/embed/?type=library)](http://os-doc-builder.test.mbed.com/docs/development/mbed-os-api-doxy/class_wi_fi_interface.html)
 
 ### Usage
 
-To bring up the network interface:
+To bring up the network interface of external Wi-Fi device (for example, the ESP8266Interface):
+
+1. Instantiate an implementation of the WiFiInterface class.
+    1. Initialises AT command parser.
+1. Call the `connect` function with an SSID and password for the Wi-Fi network.
+    1. Commands Wi-Fi device to connect to network.
+1. Once connected, the WiFiInterface can be used as a target for opening [network sockets](/docs/development/reference/network-socket.html).
+
+To bring up the network interface of Ethernet like driver (for example, the OdinWiFiInterface):
 
-1. Instantiate an implementation of the WiFiInterface class (for example, the ESP8266Interface).
+1. Instantiate an implementation of the WiFiInterface class.
+    1. Initialises Wifi driver for the target.
+    1. Initialises network stack (LWIP). 
 1. Call the `connect` function with an SSID and password for the Wi-Fi network.
+    1. Wi-Fi driver connects to Wi-Fi network.
+    2. Network stack accuires IP address and DNS server address.
+
 1. Once connected, the WiFiInterface can be used as a target for opening [network sockets](/docs/development/reference/network-socket.html).
 
+### Troubleshooting information
+
+Network interface `connect` failure reasons:
+1. Check that SSID and password are correct.
+1. Check that the IP address configuration service is working.
+
 ### Wi-Fi example
 
 Here is an example of an HTTP client program. The program brings up an ESP8266 as the underlying network interface, and uses it to perform an HTTP transaction over a TCPSocket: