Update EthInterface.md

Make changes from PR #472 to live site after reviewing on test site.

Author: Amanda Butler

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

@@ -4,18 +4,53 @@
 
 The EthInterface provides a C++ API for connecting to the internet over Ethernet.
 
-### EthInterface class reference
-
-[![View code](https://www.mbed.com/embed/?type=library)](https://os.mbed.com/docs/v5.8/mbed-os-api-doxy/class_eth_interface.html)
+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
 
-To bring up the network interface:
+To statically initialize the driver, create an object without passing any parameters:
+
+```cpp
+EthernetInterface eth;
+```
+
+Then, if the default configuration is enough, bring up the interface:
+
+```cpp
+nsapi_error_t status = eth.connect();
+```
+
+Now, the interface is ready to be used for [network sockets](/docs/development/reference/network-socket.html).
+
+```cpp
+// Open a TCP socket
+TCPSocket socket;
+socket.open(&eth);
+
+// Open a UDP socket
+UDPSocket socket;
+socket.open(&eth);
+```
+
+### Configuration
 
-1. Instantiate the `EthInterface` class.
-1. Call the `connect` function.
-1. Once you connect the EthInterface, you can use it as a
-target for opening [network sockets](/docs/v5.8/reference/network-socket.html).
+For EthernetInterface, there are two possible configurations:
+
+- Use DHCP for network addressing. This is the default.
+- Use statically configured IP addresses.
+
+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:
+
+- `NSAPI_ERROR_NO_CONNECTION` indicates that the Ethernet link up has failed. Check that the Ethernet connection is working.
+- `NSAPI_ERROR_DHCP_FAILURE` indicates that acquiring the 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)](https://os.mbed.com/docs/v5.8/mbed-os-api-doxy/class_eth_interface.html)
 
 ### EthInterface examples