In A/Gb and Iu mode an MS and the core network may negotiate the use of extended idle mode DRX as described in TS 23.682. If the MS decides to request for extended idle mode DRX, the MS includes an extended idle mode DRX parameters information element in the attach request and/or RAU request message. The MS shall also include the DRX parameters for regular idle mode DRX in attach request. The SGSN decides whether to accept or reject the MS request for enabling extended idle mode DRX as described in TS 23.682. In case the SGSN accepts the extended idle mode DRX, the SGSN based on operator policies and, if available, the extended idle mode DRX cycle length value in the subscription data from the HLR/HSS, may also provide different values of the extended idle mode DRX parameters than what was requested by the MS. If the SGSN accepts the use of extended idle mode DRX, the MS shall apply extended idle mode DRX based on the received extended idle mode DRX parameters. If the MS does not receive the extended idle mode DRX parameters information element in the relevant accept message because the SGSN rejected its request or because the request was received by SGSN not supporting extended idle mode DRX, the MS shall apply its regular discontinuous reception. When the MS has PDP context for emergency bearer services, the MS and SGSN follow regular discontinuous reception as defined in clause 8.1.2 / 8.2.3 and shall not use the extended idle mode DRX. Extended idle mode DRX parameters may be negotiated while the MS has PDP context for emergency bearer services. When the PDP context for emergency bearer services is deactivated, the MS and SGSN shall reuse the negotiated extended idle mode DRX parameters in the last RAU/Attach procedure. The MS shall include the extended idle mode DRX parameters information element in each RAU message if it still wants to use extended idle mode DRX. At SGSN to SGSN, MME to SGSN and SGSN to MME mobility, the extended idle mode DRX parameters are not sent from the old CN node to the new CN node as part of the MM context information. If the SGSN is requested to monitor Reachability for Data and the UE is about to become reachable for paging, the SGSN sends a Monitoring Report message to the address that was indicated in the related Monitoring Request as described in TS 23.682.

To determine the occurrence of ongoing paging group occurences for a given MS the SGSN uses the extended idle mode DRX parameters and a parameter called "time remaining until the next paging group occurence" received from the BSS for that MS see TS 48.018. If the SGSN needs to page the MS for which the SGSN has received the extended idle mode DRX parameters while the "time remaining until the next paging group occurence" parameter is not available, SGSN sends a paging message without concern for the next paging group occurrence. In that case BSS may respond to the SGSN with an indication that the paging message was not sent on the radio interface in which case the BSS includes the "time remaining until the next paging group occurence" parameter. The SGSN shall then reattempt the page taking the extended idle mode DRX parameters and the "time remaining until the next paging group occurence" parameter of the MS into consideration. The value of the extended idle mode DRX cycle remains valid for the device (unless renegotiated) regardless of whether an SGSN actually triggers the transmission of a page to that device using any of the ongoing paging group occurences. After reception of a BSS restart indication, the SGSN sends to the BSS a Dummy Paging message including a IMSI and the extended idle mode DRX parameters to the BSS. BSS will for this Dummy Page message calculate the "time remaining until the next paging group occurence" and reply back to the SGSN including the "time remaining until the next paging group occurrence" in a Dummy Paging response. SGSN will use that "time remaining until the next paging group occurence" information to adjust the paging timing for all MSs that are subject to extended Idle mode DRX.

The extended idle mode DRX parameters are valid until the next Attach/RAU procedure is conducted and comprise the extended Idle DRX cycle value and Paging Transmission Window. The MS and the SGSN coordinate the start of the Paging Transmission Window as described in TS 23.682. The MS monitors the network for paging messages during the Paging Transmission Window using its regular DRX parameters.

GPRS radio resource management procedures are required for the following functions:

• allocation and release of physical resources (i.e. timeslots) associated with a GPRS channel;
• monitoring GPRS channel utilisation to detect under-utilised or congested GPRS channels;
• initiating congestion control procedures; and
• distribution of GPRS channel configuration information for broadcasting to the MSs.

The radio resource management features that are required for PS handover are detailed in TS 43.129.

The RAN Information Management (RIM) procedures provide a generic mechanism for the exchange of arbitrary information between applications belonging to the RAN nodes. The RAN information is transferred via the SGSN core network node(s). In order to make the RAN information transparent for the Core Network, the RAN information is included in a RIM container that shall not be interpreted by the Core Network nodes. The RIM procedures are optional both in the RAN node and in the SGSN. For the Gb interface the use of RIM procedures is negotiated at start/restart of the Gb link. For the Iu interface there is no negotiation of using RIM procedures or not at Iu link start/restart. The RAN information is transferred in RIM containers from the source RAN node to the destination RAN node by use of messages. Each message carrying the RIM container is routed and relayed independently by the SGSN(s). Any relation between messages is transparent for the SGSN, i.e. a request/response exchange between RIM applications, for example, is routed and relayed as two independent messages by the SGSN. The interfaces which will be used are the Gb (BSSGP) , the Iu (RANAP), the Gn (GTPv1) and the S16 (GTPv2) interfaces. The RAN information in the RIM container shall be transparent for the Core Network. An SGSN supporting the RIM procedures provides addressing, routeing and relay functions.

The RAN node applications, which use the RIM procedures, are fully transparent for the SGSN. These applications are described in RAN specifications. An example is the Network Assisted Cell Change described in TS 48.018 and TS 25.413.