Cisco Cisco ASR 5000
S4-SGSN Suspend-Resume Feature
▀ Feature Description
▄ SGSN Administration Guide, StarOS Release 18
Feature Description
The S4-SGSN Suspend/Resume feature provides support for suspend/resume procedures from the BSS and a peer S4-
SGSN.
SGSN.
When a UE is in a 2G coverage area wants to make a circuit switched voice call but the Class A mode of operation is
not supported by the network, then the packet switched data session (PDP contexts) must be suspended before the voice
call can be made. In this case, the BSS sends a Suspend Request to the SGSN. If the UE is already attached at that
SGSN then the suspend request is handled via an intra-SGSN suspend/resume procedure. If the UE is not attached at the
SGSN then the Suspend Request is forwarded to a peer SGSN/MME through GTPv2 and an inter-SGSN/SGSN-MME
suspend procedure occurs. Once the UE completes the voice call, either the BSS sends a resume request to resume the
suspended PDPs or the UE directly sends a Routing Area Update Request (RAU) in 2G which will be treated as an
implicit resume.
not supported by the network, then the packet switched data session (PDP contexts) must be suspended before the voice
call can be made. In this case, the BSS sends a Suspend Request to the SGSN. If the UE is already attached at that
SGSN then the suspend request is handled via an intra-SGSN suspend/resume procedure. If the UE is not attached at the
SGSN then the Suspend Request is forwarded to a peer SGSN/MME through GTPv2 and an inter-SGSN/SGSN-MME
suspend procedure occurs. Once the UE completes the voice call, either the BSS sends a resume request to resume the
suspended PDPs or the UE directly sends a Routing Area Update Request (RAU) in 2G which will be treated as an
implicit resume.
The ability for a GPRS user to access circuit-switched services depends on the subscription held, the network
capabilities, and the MS capabilities.
capabilities, and the MS capabilities.
Suspension of GPRS Services
The MS sends a request to the network for the suspension of GPRS services when the MS or the network limitations
make it unable to communicate on GPRS channels in one or more of the following scenarios:
make it unable to communicate on GPRS channels in one or more of the following scenarios:
1. A GPRS-attached MS enters dedicated mode and the support of the Class A mode of operation is not possible
(for example, the MS only supports DTM and the network only supports independent CS and PS).
2. During CS connection, the MS performs a handover from Iu mode to A/Gb mode, and the MS or the network
limitations make it unable to support CS/PS mode of operation, (for example, an MS in CS/PS mode of
operation in Iu mode during a CS connection reverts to class-B mode of operation in A/Gb mode).
operation in Iu mode during a CS connection reverts to class-B mode of operation in A/Gb mode).
3. When an MS in class A mode of operation is handed over to a cell where the support of Class A mode of
operation is not possible (for example, a DTM mobile station entering a cell that does not support DTM).
Relationships to Other Features
One of the following configurations must exist on the SGSN for the Suspend Resume feature to work properly on the
S4-SGSN:
S4-SGSN:
2G SGSN Service + S4-SGSN Support
3G SGSN Service + S4-SGSN Support
2G SGSN Service + 3G SGSN Service + S4-SGSN Support
Configuration procedures for the above deployments are available in the ASR 5000 Serving GPRS Support Node
Administration Guide.
Administration Guide.