DOCS-924 rewrite faq entry on mongos connections

source/faq/sharding.txt

@@ -193,23 +193,23 @@ behavior.
 How many connections does each ``mongos`` need?
 -----------------------------------------------
 
-Typically, each client maintains as connection to
-:program:`mongos`. :program:`mongos` maintains a connection pool to
-support a single outgoing connection to each shard for. For incoming
-connections that direct read operations to secondaries, the
-:program:`mongos` will also need to maintain connects to each member
-of the replica set that provides the shard.
-
-Why does ``mongos`` hold connections?
--------------------------------------
+Each client maintains a connection to a :program:`mongos` instance.
+Each :program:`mongos` instance maintains a pool of connections to
+the members of a replica set supporting the sharded cluster.
+Connections between :program:`mongos` and :program:`mongod` instances
+are used by one client at a time (requests are not multiplexed or
+pipelined) and then returned to the connection pool.
+
+Why does ``mongos`` hold connections open?
+------------------------------------------
 
 :program:`mongos` uses a set of connection pools to communicate with
 each :term:`shard`.  These pools do not shrink when the number of
 clients decreases.
 
-This can lead to an unused :program:`mongos` with a large number open
-of connections. If the :program:`mongos` is no longer in use, you're
-safe restarting the process to close existing connections.
+This can lead to an unused :program:`mongos` with a large number
+of open connections. If the :program:`mongos` is no longer in use,
+it is safe to restart the process to close existing connections.
 
 Where does MongoDB report on connections used by ``mongos``?
 ------------------------------------------------------------

source/reference/mongos.txt

@@ -1,10 +1,10 @@
+.. default-domain:: mongodb
 .. _mongos:
 
 ==========
 ``mongos``
 ==========
 
-.. default-domain:: mongodb
 
 Synopsis
 --------
@@ -17,23 +17,20 @@ From the perspective of the application, a
 :program:`mongos` instance behaves identically to any other MongoDB
 instance.
 
-.. seealso::
-
-   See the ":wiki:`Sharding`" wiki page for more information regarding
-   MongoDB's sharding functionality.
-
-.. STUB ":doc:`/core/sharding`"
-
 .. note::
 
    .. versionchanged:: 2.1
-
    Some aggregation operations using the :dbcommand:`aggregate` will
    cause :program:`mongos` instances to require more CPU resources
    than in previous versions. This modified performance profile may
-   dictate alternate architecture decisions if you make use the
+   dictate alternate architecture decisions if you use the
    :term:`aggregation framework` extensively in a sharded environment.
 
+.. seealso::
+
+   * :doc:`/sharding`
+   * :doc:`/core/sharding`
+
 Options
 -------
 
@@ -252,8 +249,8 @@ Options
 
    .. versionadded:: 2.2
 
-   :option:`--localThreshold` affects the logic that program:`mongos`
-   uses when selecting :term:`replica set` members to pass reads
+   :option:`--localThreshold` affects the logic that :program:`mongos`
+   uses when selecting :term:`replica set` members to pass read
    operations to from clients. Specify a value to
    :option:`--localThreshold` in milliseconds. The default value is
    ``15``, which corresponds to the default value in all of the client

source/sharding.txt

@@ -73,6 +73,7 @@ Reference
 The following reference section describes sharding commands:
 
 - :ref:`sharding-commands`
+- :ref:`faq/sharding.txt`
 
 .. STUB tutorial/replace-one-configuration-server-in-a-shard-cluster
 .. STUB tutorial/replace-all-configuration-servers-in-a-shard-cluster