doc: tracing: net: Add information for network tracing

Add a simple documentation page that describes the network
tracing support.

Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>

doc/connectivity/networking/index.rst

@@ -15,5 +15,6 @@ operation of the stacks and how they were implemented.
    net_config_guide.rst
    networking_with_host.rst
    network_monitoring.rst
+   network_tracing.rst
    api/index.rst
    conn_mgr/index.rst

doc/connectivity/networking/network_tracing.rst

@@ -0,0 +1,26 @@
+.. _network_tracing:
+
+Network Tracing
+###############
+
+.. contents::
+    :local:
+    :depth: 2
+
+User can enable network core stack and socket API calls tracing.
+
+The :kconfig:option:`CONFIG_TRACING_NET_CORE` option contols the core network
+stack tracing. This option is enabled by default if tracing and networking
+are enabled. The system will start to collect the receiving and sending call
+verdicts i.e., whether the network packet was successfully sent or received.
+It will also collect packet sending or receiving timings i.e., how long
+it took to deliver the network packet, and the network interface, priority
+and traffic class used.
+
+The :kconfig:option:`CONFIG_TRACING_NET_SOCKETS` option can be used to track
+BSD socket call usage in the system. It is enabled if tracing and BSD socket
+API support are enabled. The system will start to collect what BSD socket
+API calls are made and what parameters the API calls are using and returning.
+
+See the :ref:`tracing documentation <tracing>` for how to use the tracing
+service.

doc/services/tracing/index.rst

@@ -740,3 +740,13 @@ Syscalls
 ========
 
 .. doxygengroup:: subsys_tracing_apis_syscall
+
+Network tracing
+===============
+
+.. doxygengroup:: subsys_tracing_apis_net
+
+Network socket tracing
+======================
+
+.. doxygengroup:: subsys_tracing_apis_socket