A transport connection is a connection used to transport user data. MAC management messages are not carried on transport connections. A transport connection is identified by a transport connection identifier, a unique identifier taken from the CID address space that uniquely identifies the transport connection.
A set of MAC management messages is defined. These messages are carried in the payload of a MAC PDU starting with a generic MAC header. All MAC management messages begin with a management message Type field and may contain additional fields. This field is 1 byte long. The format of the MAC management message is given in Figure 8.8.
Management Massage Payload
MAC management messages on the basic, broadcast and initial ranging connections can neither be fragmented nor packed. MAC management messages on the primary management connection and the secondary management connection may be packed and/or fragmented. For the SCa, OFDM and OFDMA PHY layers, management messages carried on the initial ranging, broadcast, basic and primary management connections must have a CRC field.
The list of 802.16-2004 MAC management messages and the encoding of their management message Type field are given in Table 8.5. The 802.16e amendment added some new messages, given in Table 8.6. The new messages related to mobility start with MOB. In Annex A, the different sets of MAC management messages and the descriptions of these messages are shown. Many of these messages will be used in the following chapters.
MAC management messages very often include TLV encoding. TLV encoding is introduced in the next section.