Tunnel Management Messages

Message Type                          Used by  Description

Create PDP Context Request/ Response

Update PDP Context Request/ Response

GTP-C      Sent from an SGSN to a GGSN node as part of a GPRS PDP Context Activation procedure or the Network-Requested PDP Context Activation procedure. A valid request initiates the cre- ation of a tunnel.

GTP-C      Used when PDP Context information changes, such as when a mobile device changes location.

Delete PDP Context Request/ Response

GTP-C      Used to terminate a PDP Context, and confirm the context has been deleted.

Create AA PDP Context

Request/ Response

GTP-C

Sent as part of the GPRS Anonymous Access PDP Context Activation. It is used to create a tunnel between a context in the SGSN and a context in the GGSN.

 

Message Type                          Used by  Description

Delete AA PDP Context

Request/ Response

GTP-C     Sent as part of the GPRS PDP Anonymous Access Context Deactivation procedure to deactivate an activated PDP Context. It contains Cause and Private Extension Information Elements

Error Indication                            GTP-U

Sent to the GGSN when a tunnel PDU is received for the fol- lowing conditions:

— No PDP context exists

— PDP context is inactive

— No MM context exists

— GGSN deletes its PDP context when the message is received.

 

PDU Notification Request/ Response/ Reject Request/ Reject Response

GTP-C      When receiving a Tunneled PDU (T-PDU), the GGSN checks if a PDP context is established for the given PDP address. If no PDP context has been established, the GGSN may initiate the Network-requested PDP Context Activation procedure by send- ing a PDU Notification Request to the SGSN.

Reject Request – Sent when the PDP context requested by the

GGSN cannot be established.

 

Location Management Messages

Message Type                          Used

By

Description

 

Send Routing Information for

GPRS Request/ Response

GTP-C      Sent by the GGSN to obtain location information for the MS.

This message type contains the IMSI of the MS and Private

Extension.

 

Sent by the GGSN to the HLR when a PDU reject message is received.

Failure Report Request/ Response

GTP-C

The GGSN requests the HLR to set the flag and add the GGSN to the list of nodes to report to when activity from the subscriber that owns the PDP address is detected.

The message contains the subscriber IMSI and Private Exten- sion

Note MS GPRS Present

Request/ Response

GTP-C      When the HLR receives a message from a mobile with MDFG

set, it clears the MDFG and sends the Note MS Present mes- sage to all GGSN’s in the subscriber’s list.

This message type contains subscriber IMSI, GSN Address and

Private Extension