diff --git a/message/message.go b/message/message.go
index d999047..bf6d40e 100644
--- a/message/message.go
+++ b/message/message.go
@@ -9,18 +9,25 @@ import (
 
 type messageID uint8
 
-// Message ID
 const (
-	MsgChoke         messageID = 0
-	MsgUnchoke       messageID = 1
-	MsgInterested    messageID = 2
+	// MsgChoke chokes the receiver
+	MsgChoke messageID = 0
+	// MsgUnchoke unchokes the receiver
+	MsgUnchoke messageID = 1
+	// MsgInterested expresses interest in receiving data
+	MsgInterested messageID = 2
+	// MsgNotInterested expresses disinterest in receiving data
 	MsgNotInterested messageID = 3
-	MsgHave          messageID = 4
-	MsgBitfield      messageID = 5
-	MsgRequest       messageID = 6
-	MsgPiece         messageID = 7
-	MsgCancel        messageID = 8
-	MsgPort          messageID = 9
+	// MsgHave alerts the receiver that the sender has downloaded a piece
+	MsgHave messageID = 4
+	// MsgBitfield encodes which pieces that the sender has downloaded
+	MsgBitfield messageID = 5
+	// MsgRequest requests a block of data from the receiver
+	MsgRequest messageID = 6
+	// MsgPiece delivers a block of data to fulfill a request
+	MsgPiece messageID = 7
+	// MsgCancel cancels a request
+	MsgCancel messageID = 8
 )
 
 // Message stores ID and payload of a message