ncrypted depending on their function. A MAC management message included in a MAC PDU whose encryption control bit value does not match the combined message type and corresponding context is discarded. Encrypted and unencrypted MAC control messages are not sent in the same PDU. The MAC management messages shown in Table 6-8 are sorted based on their usage, e.g., Network entry/re- entry, Sleep Mode operation, Idle Mode operation, etc. The IEEE 802.16-2009 standard corre- sponding MAC management messages (if applicable) are also included in the table to help better understanding of the similarities and differences. Note that legacy MAC management messages, depending on their types, are carried over basic or primary management connections, as well as broadcast or initial ranging connections, whereas in IEEE 802.16m, the type of connections for carrying MAC control messages (as shown in Table 6-8) are classified as unicast, broadcast, and initial ranging. xii Abstract Syntax Notation One (ASN.1) is a standard for describing a message that can be sent or received in a network. ASN.1 is divided into two parts: (1) the rules of syntax for describing the contents of a message in terms of data type and content sequence or structure; and (2) how each data item is encoded in a message. ASN.1 is defined in two ISO standards for applications intended for the Open Systems Interconnection framework [16,17]. The following is an example of a message definition specified with ASN.1 notation: Report:: SEQUENCE {author OCTET STRING, title OCTET STRING, body OCTET STRING, biblio Bibliography} In this example, Report is the name of this type of message. SEQUENCE indicates that the message is a sequence of data items. The first four data items have the data type of OCTET STRING, meaning each is a string of bytes. The bibli- ography data item is another definition named Bibliography that is used. Bibliography:: SEQUENCE {author OCTET STRING title OCTET STRING publisher OCTET STRING year OCTET STRING} Other data types that can be specifie