cast connections are identified by the combination of a 12-bit STID and a 4-bit FID. Multicast and broadcast connections are identified by the reserved STIDs. In IEEE 802.16m, the connections are classified as management connections and transport connections. Management connections carry MAC control messages. Transport connections, on the other hand, are used to carry user data including upper layer signaling such as DHCP, as well as data-plane signaling such as ARQ feedback. The MAC control messages are never transferred over transport connections and user data is never transferred over management connections. One pair of bi- directional (DL/UL) unicast management/control connections are automatically established when an MS performs initial network entry. An FID with value "0" is reserved for this pair of connections. The mapping between MAC control messages and connection types is static, as shown in Table 6-8. Therefore, there is a difference between the notion of connection in IEEE 802.16m and the legacy standard. In IEEE 802.16m, connections are either management (bi-directional for unicast and uni-directional for broadcast connections) or transport (uni- directional). Once the Temporary STID is allocated to the MS, the management connections are established automatically. The FIDs for the management connections are not changed during handover or network re-entry between IEEE802.16m compliant systems. All user data communications use transport connections. A transport connection is uni-directional and established with a unique FID that is assigned using a Dynamic Service Addition (DSA) procedure. If the Group Create/Change parameter is included in a DSA message, it would indicate that a group of coupled transport connections must be considered together on admission. Each transport connection is associated with an active service flow to provide various levels of QoS required by the service flow. The transport connections are established when the associated active service flows are created, and are released wh