Add some nice documentation.

diff --git a/wcfsetup/install/files/lib/data/session/virtual/SessionVirtual.class.php b/wcfsetup/install/files/lib/data/session/virtual/SessionVirtual.class.php
index 2c2dc38b3338a693ffad2776a0351a6c1837d822..a6226c9ea79ff11d27c39790c9a8811db0981149 100644 (file)
--- a/wcfsetup/install/files/lib/data/session/virtual/SessionVirtual.class.php
+++ b/wcfsetup/install/files/lib/data/session/virtual/SessionVirtual.class.php
@@ -5,7 +5,13 @@ use wcf\system\WCF;
 use wcf\util\UserUtil;
 
 /**
- * Represents a virtual session.
+ * Virtual Sessions extend the original session system with a transparent layer. 
+ * It's only purpose is to enforce session validation based on IP address and/or user agent.
+ *
+ * The legacy session system does not allow the same user being logged-in more than once 
+ * and the same is true for WCF 2.1 unless we break most parts of the API. 
+ * In order to solve this, we do allow multiple clients to share the exact same session 
+ * among them, while the individual clients are tracked within wcf1_session_virtual.
  * 
  * @author     Alexander Ebert
  * @copyright  2001-2014 WoltLab GmbH