Cisco Cisco ASR 5000
SGSN-MME Combo Optimization
▀ How It Works
▄ SGSN Administration Guide, StarOS Release 18
Flows
This section includes various diagrams that illustrate the session manager (SessMgr) selection logic during RAU, SRNS,
and Attach procedures:
and Attach procedures:
Figure 90. Selection of SessMgr Instance during RAU from MME to SGSN
Listed below is the SessMgr instance selection logic during a RAU procedure from the MME to SGSN:
1. A RAU request from UE is forwarded to the LinkMgr or GbMgr.
2. The LinkMgr identifies if the RAU is local and extracts the SessMgr instance from the PTMSI and forwards the
2. The LinkMgr identifies if the RAU is local and extracts the SessMgr instance from the PTMSI and forwards the
request to IMSIMgr.
3. The IMSIMgr tries to select the SessMgr instance extracted from the PTMSI and forwards the request to the
selected SessMgr.
Figure 91. Selection of SessMgr Instance during SRNS
Listed below is the SessMgr instance selection logic during an SRNS procedure:
1. During an SRNS procedure, the MME service sends a Forward Relocation Request to the EGTPCMgr.
2. The EGTPCMgr forwards the request to the IMSIMgr.
2. The EGTPCMgr forwards the request to the IMSIMgr.