Cisco Cisco ASR 5000
SGSN Serving Radio Network Subsystem Relocation
How it Works ▀
SGSN Administration Guide, StarOS Release 18 ▄
Step
Description
14
The new SGSN sends a Forward SRNS Context message to the new RNC. At this point, the UE detaches from the old RNC
and attaches to the new RNC.
and attaches to the new RNC.
15
The source RNC should start direct forwarding of downlink data from the source RNC towards the target RNC for bearers
subject to data forwarding.
subject to data forwarding.
16
The UE sends an RRC message to the new RNC. Downlink packets forwarded from the old RNC can be sent to the UE. In
addition, uplink packets can be sent from the UE, which are forwarded to the new SGW and then on to the PGW.
addition, uplink packets can be sent from the UE, which are forwarded to the new SGW and then on to the PGW.
17
The new RNC sends a Relocation Complete message to the new SGSN.
18
The new SGSN then ends a Forward Relocation Complete Notification message to the old SGSN.
19
The old SGSN sends a Forward Relocation Complete Acknowledgement message to the new SGSN.
20
The new SGSN sends a Modify Bearer Request message to the new SGW for each PDN connection.
21
The new SGW sends a Modify Bearer Request message to the PGW.
22
The PGW sends a Modify Bearer Response message to the new SGW.
23
The new SGW sends a Modify Bearer Response message to the new SGSN. The PGW begins sending downlink packets to
the new SGW, which in turn sends them to the new RNC, and then to the UE.
the new SGW, which in turn sends them to the new RNC, and then to the UE.
24
The UE initiates a Routing Area Update procedure. This RAU occurs on a RANAP Direct Transfer and therefore does not
involve a Context transfer with the peer SGSN.
involve a Context transfer with the peer SGSN.
25
The old SGSN sends a Delete Session Request to the old SGW.
26
The old SGSN sends an Iu Release Command to the old RNC.
27
The old RNC then sends a Iu Release Complete message to the old SGSN.
28
The old SGW sends a Delete Session Response message to the old SGSN.
Standards Compliance
The SGSN SRNS Relocation feature complies with the following standards:
SGSN Gn/Gp SRNS Relocation: 3GPP TS 23.060 V8.10.0 (2010-09): 3rd Generation Partnership Project;
Technical Specification Group Services and System Aspects; General Packet Radio Service (GPRS); Service
description; Stage 2 (Release 8)
description; Stage 2 (Release 8)
S4-SGSN (S3/S16) SRNS Relocation: 3GPP TS 23.060 V9.8.0 (2011-03): 3rd Generation Partnership Project;
Technical Specification Group Services and System Aspects; General Packet Radio Service (GPRS); Service
description; Stage 2 (Release 9)
description; Stage 2 (Release 9)
MME to 3G SGSN Hard Handover and Relocation: LTE; General Packet Radio Service (GPRS)
enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access (3GPP TS 23.401
version 9.8.0 Release 9)
version 9.8.0 Release 9)