[DOCS-10829] Update network analytics page (#29476)

* add traffic flows explanation

* small fix

* Apply suggestions from code review

Co-authored-by: Bryce Eadie <bryce.eadie@datadoghq.com>

---------

Co-authored-by: Bryce Eadie <bryce.eadie@datadoghq.com>

Author: Alicia Scott

content/en/network_monitoring/cloud_network_monitoring/network_analytics.md

@@ -55,9 +55,20 @@ The next example shows all aggregate connections from IP addresses representing
 
 You can further aggregate to isolate to traffic where the client or server matches a CIDR using `CIDR(network.client.ip, 10.0.0.0/8)` or `CIDR(network.server.ip, 10.0.0.0/8)`.
 
-Additionally, set the timeframe over which traffic is aggregated using the time selector at the top right of the page:
+### Understanding client and server roles in relation to traffic direction
 
-{{< img src="network_performance_monitoring/network_analytics/npm_timeframe.png" alt="Time frame CNM" style="width:30%;">}}
+The Network Analytics page shows directional traffic flows from clients in one zone to servers in another. These flows are not symmetrical and may not show equal "bytes sent" and "bytes received" when reversed.
+
+In this context:
+
+- Client refers to the side that initiates the connection.
+- Server is the side that responds to that connection.
+
+Datadog monitors traffic based on who opened the connection. The reverse direction (server to client) is shown as a separate flow and may have different volume metrics, or no data at all if no connections are initiated in that direction.
+
+For example, if a client in `us-east-1d` talks to a server in `us-east-1c`, you may see significant traffic. However, if there is no server in `us-east-1d`, the reverse row (`us-east-1c → us-east-1d`) may show little or no data.
+
+**Note**: Asymmetries in traffic can also result from application behavior or infrastructure elements (for example, proxies or NATs), or lack of connection initiation in one direction.
 
 ### Recommended queries