diff --git a/common/loader/type.proto b/common/loader/type.proto
index 7e8ae0c2d..d311f01bc 100644
--- a/common/loader/type.proto
+++ b/common/loader/type.proto
@@ -5,7 +5,10 @@ option go_package = "loader";
 option java_package = "com.v2ray.core.common.loader";
 option java_outer_classname = "TypeProto";
 
+// Serialized proto message along with its type name.
 message TypedSettings {
+  // The name of the message type, retrieved from protobuf API.
   string type = 1;
+  // Serialized proto message. 
   bytes settings = 2;
 }
\ No newline at end of file
diff --git a/config.proto b/config.proto
index e9c4e07b4..eb03d4217 100644
--- a/config.proto
+++ b/config.proto
@@ -12,6 +12,7 @@ import "v2ray.com/core/common/log/config.proto";
 import "v2ray.com/core/transport/internet/config.proto";
 import "v2ray.com/core/transport/config.proto";
 
+// Configuration serialization format.
 enum ConfigFormat {
   Protobuf = 0;
   JSON = 1;
@@ -40,34 +41,54 @@ message AllocationStrategy {
   Type type = 1;
 
   // Number of handlers (ports) running in parallel.
+  // Default value is 3 if unset.
   AllocationStrategyConcurrency concurrency = 2;
 
   // Number of minutes before a handler is regenerated.
+  // Default value is 5 if unset.
   AllocationStrategyRefresh refresh = 3;
 }
 
 // Config for an inbound connection handler.
 message InboundConnectionConfig {
+  // Protocol specific settings. Must be one of the supported protocols.
   v2ray.core.common.loader.TypedSettings settings = 1;
+
+  // Range of port number to run on. Both inclusive.
   v2ray.core.common.net.PortRange port_range = 2;
+
+  // IP address to listen on. 0.0.0.0 if unset.
   v2ray.core.common.net.IPOrDomain listen_on = 3;
+
+  // Tag of this handler.
   string tag = 4;
+
   AllocationStrategy allocation_strategy = 5;
+
   v2ray.core.transport.internet.StreamConfig stream_settings = 6;
+
   bool allow_passive_connection = 7;
 }
 
+// Config for an outbound connection handler.
 message OutboundConnectionConfig {
   v2ray.core.common.loader.TypedSettings settings = 1;
+
+  // IP address to send data through. 0.0.0.0 if unset.
   v2ray.core.common.net.IPOrDomain send_through = 2;
   v2ray.core.transport.internet.StreamConfig stream_settings = 3;
   string tag = 4;
 }
 
 message Config {
+  // Inbound handler configurations. Must have at least one item.
   repeated InboundConnectionConfig inbound = 1;
+
+  // Outbound handler configurations. Must have at least one item. The first item is used as default for routing.
   repeated OutboundConnectionConfig outbound = 2;
   v2ray.core.common.log.Config log = 3;
+
+  // App configuration. Must be one in the app directory.
   repeated v2ray.core.common.loader.TypedSettings app = 4;
   v2ray.core.transport.Config transport = 5;
 }
\ No newline at end of file
diff --git a/transport/internet/config.proto b/transport/internet/config.proto
index d31be10af..b5cc8a6ea 100644
--- a/transport/internet/config.proto
+++ b/transport/internet/config.proto
@@ -8,13 +8,21 @@ import "v2ray.com/core/common/net/network.proto";
 import "v2ray.com/core/common/loader/type.proto";
 
 message NetworkSettings {
+  // Type of network that this settings supports.
   v2ray.core.common.net.Network network = 1;
+
+  // Specific settings.
   v2ray.core.common.loader.TypedSettings settings = 2;
 }
 
 message StreamConfig {
+  // Effective network.
   v2ray.core.common.net.Network network = 1;
+
   repeated NetworkSettings network_settings = 2;
+
+  // Type of security. Must be a message name of the settings proto.
   string security_type = 3;
+  
   repeated v2ray.core.common.loader.TypedSettings security_settings = 4;
 }
\ No newline at end of file