DOCS-13977 clarify serverStatus.network ingress only

Author: andf-mongodb

source/reference/command/serverStatus.txt

@@ -1325,21 +1325,26 @@ network
 
 .. serverstatus:: network
 
-   A document that reports data on MongoDB's network use.
+   A document that reports data on MongoDB's network use. These
+   statistics measure *ingress connections* only, i.e. traffic
+   seen by the :binary:`~bin.mongod` / :binary:`~bin.mongos` over
+   network connections initiated by clients or other
+   :binary:`~bin.mongod` / :binary:`~bin.mongos` instances. Traffic from
+   network connections initiated by this :binary:`~bin.mongod` /
+   :binary:`~bin.mongos` instance (i.e. *egress connections*) is *not*
+   measured in these statistics.
 
 .. serverstatus:: network.bytesIn
 
-   The number of bytes that reflects the amount of network traffic
-   received *by* this database. Use this value to ensure that network
-   traffic sent to the :binary:`~bin.mongod` process is consistent with
-   expectations and overall inter-application traffic.
+   The total number of bytes that the server has *received* over network
+   connections initiated by clients or other :binary:`~bin.mongod` /
+   :binary:`~bin.mongos` instances.
 
 .. serverstatus:: network.bytesOut
 
-   The number of bytes that reflects the amount of network traffic sent
-   *from* this database. Use this value to ensure that network traffic
-   sent by the :binary:`~bin.mongod` process is consistent with
-   expectations and overall inter-application traffic.
+   The total number of bytes that the server has *sent* over network
+   connections initiated by clients or other :binary:`~bin.mongod` /
+   :binary:`~bin.mongos` instances.
 
 .. serverstatus:: network.numSlowDNSOperations
 
@@ -1412,8 +1417,8 @@ network
    .. versionadded:: 4.4
 
    The total number of accepted incoming TCP Fast Open (TFO) connections
-   to the :binary:`~bin.mongod`/:binary:`~bin.mongos` since the 
-   ``mongod/mongos`` last started.
+   to the :binary:`~bin.mongod` / :binary:`~bin.mongos` since the 
+   ``mongod / mongos`` last started.
 
 opLatencies
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