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Table of Contents

FortiOS Carrier

Mobility management messages

The MM procedures are used by a new SGSN in order to retrieve the IMSI and the authentication information or MM and PDP context information in an old SGSN. They are performed during the GPRS attach and the inter-SGSN routing update procedures.

The MM procedures are used between SGSNs at the GPRS-attach and inter-SGSN routing update procedures. An identity procedure has been defined to retrieve the IMSI and the authentication information in an old SGSN. This procedure may be performed at the GPRS attach. A recovery procedure enables information related to MM and PDP contexts in an old SGSN to be retrieved. This procedure is started by a new SGSN during an inter-SGSN RA update procedure.

Message Type Used By Description
Identification Request (38)
Identification Response (39)
GTP-C Sent by the new SGSN to the old SGSN to request the IMSI for a MS when a GPRS Attach is done with a P-TMSI and the MS has changed SGSNs since the GPRS Detach was done.
SGSN context Request (50) SGSN context Response (51) SGSN context Acknowledge (52) GTP-C Sent by the new SGSN to the old SGSN to request the MM and PDP Contexts for the MS.
Forward Relocation Request (53)
Forward Relocation Response (54)
Forward Relocation Complete(55)
Forward Relocation Complete Acknowledge (59)
GTP-C Indicates mobile activation/deactivation within a Routing Area. This prevents paging of a mobile that is not active (visited VLR rejects calls from the HLR or applies Call Forwarding). Note that the mobile station does not maintain an attach/detach state.

SRNS contexts contain for each concerned RAB the sequence numbers of the GTP-PDUs next to be transmitted in uplink and downlink directions.
Relocation Cancel Request (56)
Relocation Cancel Response (57)
GTP-C Send to cancel the relocation of a connection.
Forward SRNS Context (58)
Forward SRNS Context Acknowledge (60)
GTP-C This procedure may be used to trigger the transfer of SRNS contexts from RNC to CN (PS domain) in case of inter system forward handover.
RAN Information Relay (70) GTP-C Forward the Routing Area Network (RAN) information.

A Routing Area (RA) is a subset of a GSM Location Area (LA). A RA is served by only one SGSN. Ensures that regular radio contact is maintained by the mobile

UE Registration Query Request (61)
UE Registration Query Response(62)

GTP-C

The request is sent by an SGSN to an MME to support CS/PS coordination for shared UTRAN and GERAN access.

Mobility management messages

The MM procedures are used by a new SGSN in order to retrieve the IMSI and the authentication information or MM and PDP context information in an old SGSN. They are performed during the GPRS attach and the inter-SGSN routing update procedures.

The MM procedures are used between SGSNs at the GPRS-attach and inter-SGSN routing update procedures. An identity procedure has been defined to retrieve the IMSI and the authentication information in an old SGSN. This procedure may be performed at the GPRS attach. A recovery procedure enables information related to MM and PDP contexts in an old SGSN to be retrieved. This procedure is started by a new SGSN during an inter-SGSN RA update procedure.

Message Type Used By Description
Identification Request (38)
Identification Response (39)
GTP-C Sent by the new SGSN to the old SGSN to request the IMSI for a MS when a GPRS Attach is done with a P-TMSI and the MS has changed SGSNs since the GPRS Detach was done.
SGSN context Request (50) SGSN context Response (51) SGSN context Acknowledge (52) GTP-C Sent by the new SGSN to the old SGSN to request the MM and PDP Contexts for the MS.
Forward Relocation Request (53)
Forward Relocation Response (54)
Forward Relocation Complete(55)
Forward Relocation Complete Acknowledge (59)
GTP-C Indicates mobile activation/deactivation within a Routing Area. This prevents paging of a mobile that is not active (visited VLR rejects calls from the HLR or applies Call Forwarding). Note that the mobile station does not maintain an attach/detach state.

SRNS contexts contain for each concerned RAB the sequence numbers of the GTP-PDUs next to be transmitted in uplink and downlink directions.
Relocation Cancel Request (56)
Relocation Cancel Response (57)
GTP-C Send to cancel the relocation of a connection.
Forward SRNS Context (58)
Forward SRNS Context Acknowledge (60)
GTP-C This procedure may be used to trigger the transfer of SRNS contexts from RNC to CN (PS domain) in case of inter system forward handover.
RAN Information Relay (70) GTP-C Forward the Routing Area Network (RAN) information.

A Routing Area (RA) is a subset of a GSM Location Area (LA). A RA is served by only one SGSN. Ensures that regular radio contact is maintained by the mobile

UE Registration Query Request (61)
UE Registration Query Response(62)

GTP-C

The request is sent by an SGSN to an MME to support CS/PS coordination for shared UTRAN and GERAN access.