doc: Add more content for networking documentation

Jira: ZEP-687

Change-Id: Ic02f828dcc2a3994d537829832387c56f4c74ed2
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>

doc/subsystems/networking/networking.rst

@@ -7,6 +7,59 @@ The networking section contains information regarding the network stack
 of the Zephyr kernel. Use the information to understand the
 principles behind the operation of the stacks and how they were implemented.
 
+The networking stack supports the following features:
+
+* IPv6
+
+  * IPv6 header compresson, which is part of the 6LoWPAN support
+
+* UDP
+* IPv4
+
+  * In this version of the IP stack, IPv6 and IPv4 cannot be utilized at the
+    same time.
+  * DHCP client support for IPv4
+
+* TCP
+
+  * Both client and server roles are supported
+
+* RPL (Ripple) IPv6 mesh routing
+* CoAP
+* MQTT
+* Highly configurable
+
+  * Features, buffer sizes/counts, stack sizes, etc.
+
+Additionally these network technologies are supported:
+
+* IEEE 802.15.4
+* Bluetooth
+* Ethernet
+* SLIP (for testing with Qemu)
+
+Source tree layout
+==================
+
+The IP stack source code tree is organized as follows:
+
+``net/ip/``
+  The core stack itself. This is where the Contiki uIP stack code
+  is located.
+
+``include/net/``
+  Public API header files. These are the header files applications need
+  to include to use IP networking functionality.
+
+``samples/net/``
+  Sample networking code. This is a good reference to get started with
+  network application development.
+
+``tests/net/``
+  Test applications. These applications are used to verify the
+  functionality of the IP stack, but are not the best
+  source for sample code (see ``samples/net`` instead).
+
 .. toctree::
    :maxdepth: 1