e Request on Packet Associated Control Channel [PACCH]). Two types of random access bursts may be transmitted on the PRACH: an 8-information-bit random access burst or an 11- information-bit random access burst called extended packet random access burst (only the 8-information bits access burst format can be used on RACH in the GSM system or in the GPRS system if the PRACH is not used). The 11-bit format contains additional p bits to manage the request priorities that the 8-bit format does not contain. The access burst type that the MS uses in one cell is indicated through the parameter ACCESS_BURST_TYPE broadcast in the Packet System Information (PSI) on the PCCCH (if it exists). If the PRACH also does not exist, then the 8-bit format is the only one that the MS can use on the RACH. Packet Paging Channel (PPCH DL) is used for paging the mobile station prior to a mobile station receiving (terminating) data transfer. The PPCH uses paging groups to provide DRX and follows the same predefined rules as the Paging Channel (PCH) in GSM. Mobile stations in both circuit- and packet-switching modes can be paged, although this is only applicable for GPRS mobile stations class A and B. Beyond that, a mobile station engaged in a packet-switched transfer can be paged on a PACCH. PPCH is used to page the mobile station in standby mode in its routing area for a mobile telephone call before the assignment of the Packet Data Traffic Channel (PDTCH DL) on the Packet Access Grant Channel (PAGCH) of the cell where the mobile station is located. PPCH is transmitted on a normal burst. PAGCH DL for Immediate Assignment is a downlink-only channel used during the setup of a packet transfer to send Resource Assignment messages. If the mobile station is currently involved in packet transfer, then the Resource Assignment messages can be sent on the PACCH. In one-phase access or short access, PAGCH assigns several blocks. In two-phase access, PAGCH assigns one single block, on which the mobile station will send its Packet Resource Request (o