identifiers. The allocation period and number of ACIDs required for persistent operation are configured in the DL or UL Persistent A-MAP IE. In order to facilitate link adaptation and avoid resource holes, the attributes of a persistently allocated resource can be changed. To change an persistent assignment, the BS transmits the DL or UL Persistent A-MAP IEs for DL or UL reallocations. If an MS has an existing persistent allocation in a particular subframe and receives a new persistent allocation in the same subframe, the new persistent allocation replaces the original allocation. In other words, the original persistent allocation is de-allocated. When the BS sends a Persistent A-MAP IE to reallocate a persistently assigned resource, a different HARQ feedback channel must be assigned for reallocation. The reception of an ACK/NACK in the recently assigned HARQ feedback channel for the persistently assigned resource with the updated attributes will ensure that the reallocation control signaling was received correctly by the MS. xvii To facilitate inter-RAT interworking functions, the IEEE 802.16m provides a MAC control message called AAI_L2_XFER that acts as a generic service container for various services. This container is also used for IEEE 802. 16m MAC control messages that are not processed by the serving BS, but rather are processed by network entities beyond the serving BS. For example, EAP transfer is processed at the authenticator entity in the access network and it is simply relayed by the BS to the authenticator. The AAI_L2_XFER is transmitted exclusively by authenticated mobile stations. xviii- The HARQ channel identifier is used to identify HARQ channels. Each connection can have multiple concurrent HARQ channels, each of which may have a pending encoder packet transaction. CHAPTER 6 The IEEE 802. 16m MAC CPS (Part I) Asynchronous HARQ re-transmission is used for downlink persistent allocations. The DL Basic Assignment A-MAP IE is transmitted to signal control information for HARQ re-transmission. Sync