1 files changed, 3 insertions, 2 deletions
diff --git a/MdeModulePkg/Include/Library/NetLib.h b/MdeModulePkg/Include/Library/NetLib.h
index ef7bc429c1..b7ef99c7b5 100644
--- a/MdeModulePkg/Include/Library/NetLib.h
+++ b/MdeModulePkg/Include/Library/NetLib.h
@@ -422,8 +422,9 @@ NetGetIpClass (
 
   If all bits of the host address of IP are 0 or 1, IP is also not a valid unicast address,
   except when the originator is one of the endpoints of a point-to-point link with a 31-bit
-  mask (RFC3021).
-
+  mask (RFC3021), or a 32bit NetMask (all 0xFF) is used for special network environment (e.g.
+  PPP link).
+  
   @param[in]  Ip                    The IP to check against.
   @param[in]  NetMask               The mask of the IP.