7.5 Tunnel Management messages

09.603GPPGeneral Packet Radio Service (GPRS)GPRS Tunnelling Protocol GPT) across the Gn and Gp InterfaceRelease 1998TS

The Tunnel Management messages are the control and management messages, defined in GSM 03.60, used to create, update and delete tunnels to be able to route T-PDUs between a MS and an external packet data network via SGSN and GGSN. The GMM/SM messages that may trigger the sending of the Tunnel Management messages are defined in GSM 04.08.

7.5.1 Create PDP Context Request

A Create PDP Context Request shall be sent from a SGSN node to a GGSN node as a part of the GPRS PDP Context Activation procedure. The GGSN IP address where the SGSN sends the Create PDP Context Request is the first IP address in the list of IP addresses provided by the DNS server. After sending the Create PDP Context Request message, the SGSN marks the PDP context as ‘waiting for response’. In this state the SGSN shall accept G-PDUs from the GGSN but shall not send these G-PDUs to the MS. A valid request initiates the creation of a tunnel between a PDP Context in a SGSN and a PDP Context in a GGSN. If the procedure is not successfully completed, the SGSN repeats the Create PDP Context Request message to the next GGSN address in the list of IP addresses, if there is one. If the list is exhausted the activation procedure fails.

The Flow Label Data I field specifies a downlink flow label for G-PDUs which is chosen by the SGSN. The GGSN shall include this flow label in the GTP header of all subsequent downlink G-PDUs which are related to the requested PDP context.

The Flow Label Signalling field specifies a downlink flow label for signalling messages which is chosen by the SGSN. The GGSN shall include this flow label in the GTP header of all subsequent downlink signalling messages which are related to the requested PDP context.

The MSISDN of the MS is passed to the GGSN inside the Create PDP Context Request; This additional information can be used when a secure access to a remote application residing on a server is needed. The GGSN would be in fact able to provide the user identity (i. e. the MSISDN) to the remote application server, providing it with the level of trust granted to users through successfully performing the GPRS authentication procedures, without having to re-authenticate the user at the application level.

If the MS requests a dynamic PDP address and a dynamic PDP address is allowed, then the PDP Address field in the End User Address information element shall be empty. If the MS requests a static PDP Address then the PDP Address field in the End User Address information element shall contain the static PDP Address. In case the PDP addresses carried in the End User Address and optionally in the Protocol Configuration Option information element contain contradicting information, the PDP address carried in the End User Address information element takes the higher precedence. The Quality of Service Profile information element shall be the QoS values to be negotiated between the MS and the SGSN at PDP Context activation.

The SGSN shall include an SGSN Address for signalling and an SGSN address for user traffic, which may differ from that provided by the underlying network service (e.g. IP). The GGSN shall store these SGSN Addresses and use them when sending signalling on this GTP tunnel or G-PDUs to the SGSN for the MS.

The SGSN shall include a Recovery information element into the Create PDP Context Request if the SGSN is in contact with the GGSN for the very first time or if the SGSN has restarted recently and the new Restart Counter value has not yet been indicated to the GGSN. The GGSN that receives a Recovery information element in the Create PDP Context Request message element shall handle it in the same way as when receiving an Echo Response message. The Create PDP Context Request message shall be considered as a valid activation request for the PDP context included in the message.

The SGSN shall include either the MS provided APN, a subscribed APN or an SGSN selected APN in the message; the Access Point Name may be used by the GGSN to differentiate accesses to different external networks.
The Selection Mode information element shall indicate the origin of the APN in the message.

The optional Protocol Configuration Options information element is applicable for the end user protocol ‘IP’ only.

The SGSN shall select one GGSN based on the user provided or SGSN selected APN. The GGSN may have a logical name that is converted to an address. The conversion may be performed with any name-to-address function. The converted address shall be stored in the "GGSN Address in Use" field in the PDP context and be used during the entire lifetime of the PDP context.

NOTE: A DNS query may be used as the name-to-IP address mapping of the GGSN. The IP address returned in the DNS response is then stored in the "GGSN Address in Use" field in the PDP context.

The SGSN may send a Create PDP Context Request even if the PDP context is already active.

The GGSN shall check if a PDP context already exists for the TID. The existing parameters in the PDP context shall then be replaced with the parameters in the Create PDP Context Request message. If a dynamic PDP address has already been allocated for the existing context, this address should be used and copied to the Create PDP Context Response message.

If the GGSN uses the MNRG flag and the flag is set, the GGSN should treat the Create PDP Context Request as a Note MS Present Request and clear the MNRG flag.

The SGSN may include the Routeing Area Identity (RAI) of the SGSN where the MS is registered. The MCC and MNC components shall be populated with the MCC and MNC, respectively, of the SGSN where the MS is registered. The LAC and RAC components shall be populated by the SGSN with the value of ‘FFFE’ and ‘FF’, respectively.

The optional Private Extension contains vendor or operator specific information.

Table 4: Information elements in a Create PDP Context Request

Information element

Presence requirement

Reference

Routeing Area Identity (RAI)

Optional

7.9.3

Quality of Service Profile

Mandatory

7.9.6

Recovery

Optional

7.9.12

Selection mode

Mandatory

7.9.13

Flow Label Data I

Mandatory

7.9.14

Flow Label Signalling

Mandatory

7.9.15

End User Address

Mandatory

7.9.18

Access Point Name

Mandatory

7.9.21

Protocol Configuration Options

Optional

7.9.22

SGSN Address for signalling

Mandatory

GSN Address

7.9.23

SGSN Address for user traffic

Mandatory

GSN Address

7.9.23

MSISDN

Mandatory

7.9.24

Private Extension

Optional

7.9.26

7.5.2 Create PDP Context Response

The message shall be sent from a GGSN node to a SGSN node as a response of a Create PDP Context Request. When the SGSN receives a Create PDP Context Response with the Cause value indicating ‘Request Accepted’, the SGSN activates the PDP context and may start to forward T-PDUs to/from the MS from/to the external data network.

The Cause value indicates if a PDP context has been created in the GGSN or not. A PDP context has not been created in the GGSN if the Cause differs from ‘Request accepted’. Possible Cause values are:

– ‘Request Accepted’

– ‘No resources available’

– ‘Service not supported’

– ‘User authentication failed’

– ‘System failure’

– ‘Mandatory IE incorrect’

– ‘Mandatory IE missing’

– ‘Optional IE incorrect’

– ‘Invalid message format’

– ‘Version not supported’

‘No resources available’ indicates e.g. that all dynamic PDP addresses occupied or no memory available‘Service not supported’ indicates e.g. when the GGSN does not support the PDP type, PDP address or Access Point Name.
‘User authentication failed’ indicates that the external packet network has rejected the service requested by the user.

Only the Cause information element, optionally Protocol Configuration Options and optionally the Recovery information element shall be included in the response if the Cause contains another value than ‘Request accepted’.

All information elements, except Recovery, Protocol Configuration Options, and Private Extension, are mandatory if the Cause contains the value ‘Request accepted’.

The Flow Label Data I field specifies an uplink flow label for G-PDUs which is chosen by the GGSN. The SGSN shall include this flow label in the GTP header of all subsequent uplink G-PDUs which are related to the requested PDP context.

The Flow Label Signalling field specifies an uplink flow label for signalling messages which is chosen by the GGSN. The SGSN shall include this flow label in the GTP header of all subsequent uplink signalling messages which are related to the requested PDP context.

The GGSN shall include a GGSN Address for signalling and a GGSN address for user traffic, which may differ from that provided by the underlying network service (e.g. IP). The SGSN shall store these GGSN Addresses and use them when sending signalling on this GTP tunnel or G-PDUs to the GGSN for the MS.

If the MS requests a dynamic PDP address and a dynamic PDP address is allowed, then the End User Address information element shall be included and the PDP Address field in the End User Address information element shall contain the dynamic PDP Address allocated by the GGSN. In case the PDP addresses carried in the End User Address and optionally in the Protocol Configuration Option information element contain contradicting information, the PDP address carried in the End User Address information element takes the higher precedence.

The QoS values supplied in the Create PDP Context Request may be negotiated downwards by the GGSN. The negotiated values or the original values from SGSN are inserted in the Quality of Service Profile information element of the Create PDP Context Response message.

If a connection-less path is to be used to tunnel T-PDUs for the given PDP context or a reliable connection-oriented path is to be used and a connection already exists, the GGSN may start to forward T-PDUs after the Create PDP Context Response has been sent and the SGSN may start to forward T-PDUs when the Create PDP Context Response has been received. In this case the SGSN shall also be prepared to receive T-PDUs from the GGSN after it has sent a Create PDP Context Request but before a Create PDP Context Response has been received.

If a reliable connection-oriented path is to be used to tunnel T-PDUs for the given PDP context and a connection does not exist between the GSN pair, the SGSN shall establish a connection and the GGSN shall wait for the connection before forwarding of T-PDUs may start.

Only one connection shall be used between any given GSN-pair, and this connection shall be used to tunnel end user traffic in both directions.

The Reordering Required value supplied in the Create PDP Context Response indicates whether the end user protocol benefits from packet in sequence delivery and whether the SGSN and the GGSN therefore shall perform reordering or not, i.e. if reordering is required by the GGSN the SGSN and the GGSN shall perform reordering of incoming T-PDUs on this path.

The GGSN shall include the Recovery information element into the Create PDP Context Response if the GGSN is in contact with the SGSN for the first time or the GGSN has restarted recently and the new Restart Counter value has not yet been indicated to the SGSN. The SGSN receiving the Recovery information element shall handle it as when an Echo Response message is received but shall consider the PDP context being created as active if the response indicates a successful context activation at the GGSN.

The Charging ID is used to identify all charging records produced in SGSN(s) and the GGSN for this PDP context. The Charging ID is generated by the GGSN and shall be unique within the GGSN.

The Charging Gateway Address is the IP address of the recommended Charging Gateway Functionality to which the SGSN should transfer the Charging Detail Records (CDR) for this PDP Context.

The optional Private Extension contains vendor or operator specific information.

Table 5: Information elements in a Create PDP Context Response

Information element

Presence requirement

Reference

Cause

Mandatory

7.9.1

Quality of Service Profile

Conditional

7.9.6

Reordering required

Conditional

7.9.7

Recovery

Optional

7.9.12

Flow Label Data I

Conditional

7.9.14

Flow Label Signalling

Conditional

7.9.15

Charging ID

Conditional

7.9.17

End user address

Conditional

7.9.18

Protocol Configuration Options

Optional

7.9.22

GGSN Address for signalling

Conditional

GSN Address 7.9.23

GGSN Address for user traffic

Conditional

GSN Address 7.9.23

Charging Gateway Address

Optional

7.9.25

Private Extension

Optional

7.9.26

7.5.3 Update PDP Context Request

An Update PDP Context Request message shall be sent from a SGSN to a GGSN as part of the GPRS Inter SGSN Routeing Update procedure or the PDP Context Modification procedure or to redistribute contexts due to load sharing. It shall be used to change the QoS and the path. The message shall be sent by the new SGSN at the Inter SGSN Routeing Update procedure.

The Flow Label Data I field specifies a downlink flow label for G-PDUs which is chosen by the SGSN. The GGSN shall include this flow label in the GTP header of all subsequent downlink G-PDUs which are related to the requested PDP context.

The Flow Label Signalling field specifies a downlink flow label for signalling messages which is chosen by the SGSN. The GGSN shall include this flow label in the GTP header of all subsequent downlink signalling messages which are related to the requested PDP context.

The Quality of Service Profile information element shall include the QoS negotiated between the MS and SGSN at PDP Context activation or the new QoS negotiated in the PDP Context Modification procedure.

The SGSN shall include an SGSN Address for signalling and an SGSN address for user traffic, which may differ from that provided by the underlying network service (e.g. IP). The GGSN shall store these SGSN Addresses and use them when sending subsequent signalling on this GTP tunnel or G-PDUs to the SGSN for the MS. When active contexts are being redistributed due to load sharing, G-PDUs that are in transit across the Gn-interface are in an undetermined state and may be lost.

The SGSN shall include a Recovery information element into the Update PDP Context Request if the SGSN is in contact with the GGSN for the very first time or if the SGSN has restarted recently and the new Restart Counter value has not yet been indicated to the GGSN. The GGSN that receives a Recovery information element in the Update PDP Context Request message element shall handle it in the same way as when receiving an Echo Response message. The Update PDP Context Request message shall be considered as a valid update request for the PDP context indicated in the message.

The SGSN may include the Routeing Area Identity (RAI) of the SGSN where the MS is registered. The MCC and MNC components shall be populated with the MCC and MNC, respectively, of the SGSN where the MS is registered. The LAC and RAC components shall be populated by the SGSN with the value of ‘FFFE’ and ‘FF’, respectively.

The optional Private Extension contains vendor or operator specific information.

Table 6: Information elements in an Update PDP Context Request

Information element

Presence requirement

Reference

Routeing Area Identity (RAI)

Optional

7.9.3

Quality of Service Profile

Mandatory

7.9.6

Recovery

Optional

7.9.12

Flow Label Data I

Mandatory

7.9.14

Flow Label Signalling

Mandatory

7.9.15

SGSN Address for signalling

Mandatory

GSN Address 7.9.23

SGSN Address for user traffic

Mandatory

GSN Address 7.9.23

Private Extension

Optional

7.9.26

7.5.4 Update PDP Context Response

The message shall be sent from a GGSN node to a SGSN node as a response of an Update PDP Context Request.

If the SGSN receives an Update PDP Context Response with a Cause value other than ‘Request accepted’, it shall deactivate the PDP context.

Only the Cause information element and optionally the Recovery information element shall be included in the response if the Cause contains another value than ‘Request accepted’.

Possible Cause values are:

– ‘Request Accepted’

– ‘Non-existent’

– ‘Service not supported’

– ‘System failure’

– ‘Mandatory IE incorrect’

– ‘Mandatory IE missing’

– ‘Optional IE incorrect’

– ‘Invalid message format’

– ‘Version not supported’.

The Flow Label Data I field specifies an uplink flow label for G-PDUs which is chosen by the GGSN. The SGSN shall include this flow label in the GTP header of all subsequent uplink G-PDUs which are related to the requested PDP context.

The Flow Label Signalling field specifies an uplink flow label for signalling messages which is chosen by the GGSN. The SGSN shall include this flow label in the GTP header of all subsequent uplink signalling messages which are related to the requested PDP context.

The QoS values supplied in the Update PDP Context Request may be negotiated downwards by the GGSN. The negotiated values or the original value from SGSN is inserted in the Quality of Service Profile information element. This information element shall be included if the Cause contains the value ‘Request accepted’.

If a connection-less path is to be used to tunnel T-PDUs for the given PDP context or a reliable connection-oriented path is to be used and a connection already exists, the GGSN may start to forward T-PDUs after the Update PDP Context Response has been sent and the SGSN may start to forward T-PDUs when the Update PDP Context Response has been received. In this case the SGSN shall also be prepared to receive T-PDUs from the GGSN after it has sent a Update PDP Context Request but before an Update PDP Context Response has been received.

If a reliable connection-oriented path is to be used to tunnel T-PDUs for the given PDP context and a connection does not exist between the GSN pair, the SGSN shall establish a connection and the GGSN shall wait for the connection before forwarding of T-PDUs may start.

Only one connection shall be used between any given GSN-pair, and this connection shall be used to tunnel end user traffic in both directions.

The GGSN shall include a GGSN Address for signalling and an GGSN address for user traffic, which may differ from that provided by the underlying network service (e.g. IP). The SGSN shall store these GGSN Addresses and use them when sending subsequent signalling on this GTP tunnel or G-PDUs to the GGSN for the MS. When active contexts are being redistributed due to load sharing, G-PDUs that are in transit across the Gn-interface are in an undetermined state and may be lost.

The GGSN shall include the Recovery information element into the Update PDP Context Response if the GGSN is in contact with the SGSN for the first time or if the GGSN has restarted recently and the new Restart Counter value has not yet been indicated to the SGSN. The SGSN receiving the Recovery information element shall handle it as when an Echo Response message is received but shall consider the PDP context as updated and active if the response cause indicates a successful operation at the GGSN.

The Charging ID is used to identify all charging records produced in SGSN(s) and the GGSN for this PDP context. The Charging ID has been previously generated by the GGSN and is unique for this PDP context. If an inter-SGSN routing area update occurs, it is transferred to the new SGSN as part of each active PDP context.

The Charging Gateway Address is the IP address of the recommended Charging Gateway Functionality to which the SGSN should transfer the Charging Detail Records (CDR) for this PDP Context.

The optional Private Extension contains vendor or operator specific information.

Table 7: Information elements in an Update PDP Context Response

Information element

Presence requirement

Reference

Cause

Mandatory

7.9.1

Quality of Service Profile

Conditional

7.9.6

Recovery

Optional

7.9.12

Flow Label Data I

Conditional

7.9.14

Flow Label Signalling

Conditional

7.9.15

Charging ID

Conditional

7.9.17

GGSN Address for signalling

Conditional

GSN Address 7.9.23

GGSN Address for user traffic

Conditional

GSN Address 7.9.23

Charging Gateway Address

Optional

7.9.25

Private Extension

Optional

7.9.26

7.5.5 Delete PDP Context Request

A Delete PDP Context Request shall be sent from a SGSN node to a GGSN node as part of the GPRS Detach procedure or the GPRS PDP Context Deactivation procedure or from a GGSN node to a SGSN node as part of the PDP Context Deactivation Initiated by GGSN procedure. A request shall be used to deactivate an activated PDP Context.

A GSN shall be prepared to receive a Delete PDP Context Request at any time and shall always reply regardless if the PDP context exists or not.

If any collision occurs, the Delete PDP Context Request takes precedence over any other Tunnel Management message.

The optional Private Extension contains vendor or operator specific information.

Table 8: Information elements in a Delete PDP Context Request

Information element

Presence requirement

Reference

Private Extension

Optional

7.9.26

7.5.6 Delete PDP Context Response

The message shall be sent as a response of a Delete PDP Context Request.

A GSN shall ignore a Delete PDP Context Response for a non-existing PDP context.

Possible Cause value is:

– ‘Request Accepted’.

The optional Private Extension contains vendor or operator specific information.

Table 9: Information elements in a Delete PDP Context Response

Information element

Presence requirement

Reference

Cause

Mandatory

7.9.1

Private Extension

Optional

7.9.26

7.5.7 Create AA PDP Context Request

A Create AA PDP Context Request shall be sent from a SGSN node to a GGSN node as a part of the GPRS Anonymous Access PDP Context Activation procedure. It shall be used to create a tunnel between a PDP Context in a SGSN and a PDP Context in a GGSN. The GGSN IP address where the SGSN sends the Create AA PDP Context Request is the first IP address in the list of IP addresses provided by the DNS server. After sending the Create AA PDP Context Request message, the SGSN marks the PDP context as ‘waiting for response’. In this state the SGSN shall accept G-PDUs from the GGSN but shall not send these G-PDUs to the MS. If the procedure is not successfully completed, the SGSN repeats the Create AA PDP Context Request message to the next GGSN address in the list of IP addresses, if there is one. If the list is exhausted the activation procedure fails.

The Flow Label Data I field specifies a downlink flow label for G-PDUs which is chosen by the SGSN. The GGSN shall include this flow label in the GTP header of all subsequent downlink G-PDUs which are related to the requested PDP context.

The Flow Label Signalling field specifies a downlink flow label for signalling messages which is chosen by the SGSN. The GGSN shall include this flow label in the GTP header of all subsequent downlink signalling messages which are related to the requested PDP context.

The Quality of Service Profile information element shall be the QoS values to be negotiated by the MS and SGSN at Anonymous Access PDP Context activation.

The SGSN shall include a Recovery information element into the Create AA PDP Context Request if the SGSN is in contact with the GGSN for the very first time or if the SGSN has restarted recently and the new Restart Counter value has not yet been indicated to the GGSN. The GGSN that receives a Recovery information element in the Create AA PDP Context Request message element shall handle it in the same way as when receiving an Echo Response message. The Create AA PDP Context Request message shall be considered as a valid activation request for a new AA context of the indicated PDP type.

The Selection mode IE shall be set to either ‘MS provided APN, subscription not verified’ or ‘Network provided APN, subscription not verified’ depending on the origin of the APN which is included in the message.

The SGSN shall include an SGSN Address for signalling and an SGSN address for user traffic, which may differ from that provided by the underlying network service (e.g. IP). The GGSN shall store these SGSN Addresses and use them when sending signalling on this GTP tunnel or G-PDUs to the SGSN for the MS.

The End User Address contains the requested PDP Type with the PDP Address field left empty. In case the PDP addresses carried in the End User Address and optionally in the Protocol Configuration Option information element contain contradicting information, the PDP address carried in the End User Address information element takes the higher precedence.

The optional Protocol Configuration Options information element is applicable for the end user protocol ‘IP’ only. The GGSN may discard the Protocol Configuration Options information element or may use it for user authentication and configuration, depending on configuration data.

The optional Private Extension contains vendor or operator specific information.

Table 10: Information elements in a Create AA PDP Context Request

Information element

Presence requirement

Reference

Quality of Service Profile

Mandatory

7.9.6

Recovery

Optional

7.9.12

Selection mode

Mandatory

7.9.13

Flow Label Data I

Mandatory

7.9.14

Flow Label Signalling

Mandatory

7.9.15

End User Address

Mandatory

7.9.18

Access Point Name

Mandatory

7.9.21

Protocol Configuration Options

Optional

7.9.22

SGSN Address for signalling

Mandatory

GSN Address 7.9.23

SGSN Address for user traffic

Mandatory

GSN Address 7.9.23

Private Extension

Optional

7.9.26

7.5.8 Create AA PDP Context Response

The message shall be sent from a GGSN node to a SGSN node as a response of a Create AA PDP Context Request. When the SGSN receives a Create AA PDP Context Response with the Cause value indicating ‘Request Accepted’, the SGSN activates the PDP context and may start to forward T-PDUs to/from the MS from/to the external data network.

Only the Cause information element, optionally Protocol Configuration Options and optionally the Recovery information element shall be included in the response if the Cause contains another value than ‘Request accepted’.

All information elements, except Recovery, Protocol Configuration Options and Private Extension, are mandatory if the Cause contains the value ‘Request accepted’.

Possible Cause values are:

– ‘Request Accepted’

– ‘No resources available’

– ‘Service not supported’

– ‘User authentication failed’

– ‘System failure’

– ‘Mandatory IE incorrect’

– ‘Mandatory IE missing’

– ‘Optional IE incorrect’

– ‘Invalid message format’

– ‘Version not supported’.

The Flow Label Data I field specifies an uplink flow label for G-PDUs which is chosen by the GGSN. The SGSN shall include this flow label in the GTP header of all subsequent uplink G-PDUs which are related to the requested PDP context.

The Flow Label Signalling field specifies an uplink flow label for signalling messages which is chosen by the GGSN. The SGSN shall include this flow label in the GTP header of all subsequent uplink signalling messages which are related to the requested PDP context.

The GGSN shall include a GGSN Address for signalling and a GGSN address for user traffic, which may differ from that provided by the underlying network service (e.g. IP). The SGSN shall store these GGSN Addresses and use them when sending signalling on this tunnel or G-PDUs to the GGSN for the MS.

The QoS values supplied in the Create AA PDP Context Request may be negotiated downwards by the GGSN. The negotiated values or the original values from SGSN are inserted in the Quality of Service Profile information element.

If a connection-less path is to be used to tunnel T-PDUs for the given PDP context or a reliable connection-oriented path is to be used and a connection already exists, the GGSN may start to forward T-PDUs after the Create AA PDP Context Response has been sent and the SGSN may start to forward T-PDUs when the Create AA PDP Context Response has been received. In this case the SGSN shall also be prepared to receive T-PDUs from the GGSN after it has sent a Create AA PDP Context Request but before a Create AA PDP Context Response has been received.

If a reliable connection-oriented path is to be used to tunnel T-PDUs for the given PDP context and a connection does not exist between the GSN pair, the SGSN shall establish a connection and the GGSN shall wait for the connection before forwarding of T-PDUs may start.

Only one connection shall be used between any given GSN-pair, and this connection shall be used to tunnel end user traffic in both directions.

The Reordering Required value supplied in the Create AA PDP Context Response indicates whether the end user protocol benefits from packet in sequence delivery and whether the SGSN and the GGSN therefore shall perform reordering or not.

The GGSN shall include the Recovery information element into the Create AA PDP Context Response if the GGSN is in contact with the SGSN for the first time or the GGSN has restarted recently and the new Restart Counter value has not yet been indicated to the SGSN. The SGSN receiving the Recovery information element shall handle it as when an Echo Response message is received but shall consider the AA PDP context being created as active if the response indicates a successful AA context activation at the GGSN.

The Charging ID is used to identify all charging records produced in SGSN(s) and the GGSN for this PDP context. The Charging ID is generated by the GGSN and shall be unique within the GGSN.

The Charging Gateway Address is the IP address of the recommended Charging Gateway Functionality to which the SGSN should transfer the Charging Detail Records (CDR) for this PDP Context.

The PDP Address field in the End User Address information element contains the dynamic PDP Address allocated by the GGSN. In case the PDP addresses carried in the End User Address and optionally in the Protocol Configuration Option information element contain contradicting information, the PDP address carried in the End User Address information element takes the higher precedence.

The optional Private Extension contains vendor or operator specific information.

Table 11: Information elements in a Create AA PDP Context Response

Information element

Presence requirement

Reference

Cause

Mandatory

7.9.1

Quality of Service Profile

Conditional

7.9.6

Reordering Required

Conditional

7.9.7

Recovery

Optional

7.9.12

Flow Label Data I

Conditional

7.9.14

Flow Label Signalling

Conditional

7.9.15

Charging ID

Conditional

7.9.17

End User Address

Conditional

7.9.18

Protocol Configuration Options

Optional

7.9.22

GGSN Address for signalling

Conditional

GSN Address 7.9.23

GGSN Address for user traffic

Conditional

GSN Address 7.9.23

Charging Gateway Address

Optional

7.9.25

Private Extension

Optional

7.9.26

7.5.9 Delete AA PDP Context Request

A Delete AA PDP Context Request shall be sent from a SGSN node to a GGSN node as part of the GPRS PDP Anonymous Access Context Deactivation procedure. The GGSN may also send the request to the SGSN if it detects malicious usage of the service. The request shall be used to deactivate an activated PDP Context.

The Cause information element indicates whether the SGSN shall request the real identities (i.e. IMSI or IMEI) of the anonymous MS. One of the following Cause values shall be used:

– ‘Request IMSI’

– ‘Request IMEI’

– ‘Request IMSI and IMEI’

– ‘No identity needed’.

The optional Private Extension contains vendor or operator specific information.

Table 12: Information elements in a Delete AA PDP Context Request

Information element

Presence requirement

Reference

Cause

Mandatory

7.9.1

Private Extension

Optional

7.9.26

7.5.10 Delete AA PDP Context Response

The message shall be sent as a response of a Delete AA PDP Context Request.

Possible Cause values are:

– ‘Request Accepted’

– ‘Mandatory IE incorrect’

– ‘Mandatory IE missing’

– ‘Optional IE incorrect’

– ‘Invalid message format’.

If the received Delete AA PDP Context Response contains a cause value other than ‘Request accepted’, the PDP context shall be kept active.

The optional Private Extension contains vendor or operator specific information.

Table 13: Information elements in a Delete AA PDP Context Response

Information element

Presence requirement

Reference

Cause

Mandatory

7.9.1

Private Extension

Optional

7.9.26

7.5.11 Error Indication

The SGSN may send an Error Indication to the GGSN if no PDP context exists or the PDP context is inactive for a received G-PDU. The SGSN shall also send an Error Indication to the GGSN if no MM context exists for a received G-PDU.

The new SGSN sends an Error Indication to the old SGSN if no active PDP context exists for a received G-PDU.

The GGSN may send an Error Indication to the SGSN if no PDP context exists for a received G-PDU.

The GGSN shall delete its PDP context and may notify the Operation and Maintenance network element when an Error Indication is received.

The SGSN shall indicate to the MS when a PDP context has been deleted due to the reception of an Error Indication message. The MS may then request the re-establishment of the PDP context.

The old SGSN shall delete its PDP context and may notify the Operation and Maintenance network element when an Error Indication is received.

The TID used in the Error Indication message shall be fetched from the G-PDU that triggered this procedure

The optional Private Extension contains vendor or operator specific information.

Table 14: Information elements in an Error Indication

Information element

Presence requirement

Reference

Private Extension

Optional

7.9.26

7.5.12 PDU Notification Request

When receiving a T-PDU the GGSN checks if a PDP context is established for that PDP address. If no PDP context has been previously established, the GGSN may try to deliver the T-PDU by initiating the Network-Requested PDP Context Activation procedure. The criteria, used by the GGSN to determine whether trying to deliver the T-PDU to the MS or not, may be based on subscription information in the GGSN and are outside the scope of GPRS standardisation.

As part of the Network-Requested PDP Context Activation procedure the GGSN sends a PDU Notification Request message to the SGSN indicated by the HLR, i.e. the current location of the MS. When receiving this message, the SGSN shall be responsible for requesting the MS to activate the indicated PDP Context.

The IMSI is inserted in the IMSI part of the TID in the GTP header of the PDU Notification Request message. The NSAPI part of the TID is not used and shall be filled with HEX(F) by GGSN and SGSN shall ignore it.

The End User Address information element contains the PDP type and PDP address that the SGSN shall request the MS to activate.

If the GGSN receives a Create PDP Context Request before the PDU Notification Response, the GGSN shall handle the Create PDP Context Request as a normal context activation and ignore the following PDU Notification Response.

If the SGSN receives a PDU Notification Request after a Create PDP Context Request has been sent but before a Create PDP Context Response has been received, the SGSN shall only send a PDU Notification Response with Cause ‘Request accepted’ without any further processing and then wait for the Create PDP Context Response.

The optional Private Extension contains vendor or operator specific information.

Table 15: Information elements in a PDU Notification Request

Information element

Presence requirement

Reference

End User Address

Mandatory

7.9.18

Private Extension

Optional

7.9.26

7.5.13 PDU Notification Response

The message is sent by a SGSN to GGSN as a response of a PDU Notification Request.

The Cause value ‘Request accepted’ indicates if the PDP context activation will proceed. The PDP context activation procedure will not proceed for other Cause values.

Possible Cause values are:

– ‘Request Accepted’

– ‘No resources available’

– ‘Service not supported’

– ‘System failure’

– ‘IMSI not known’

– ‘MS is GPRS Detached’

– ‘GPRS connection suspended’

– ‘Mandatory IE incorrect’

– ‘Mandatory IE missing’

– ‘Optional IE incorrect’

– ‘Invalid message format’

– ‘Version not supported’

– ‘Roaming restriction’.

After an unsuccessful activation attempt the GSNs may perform some actions to prevent unnecessary enquires to the HLR as described in the section Unsuccessful Network-Requested PDP Context Activation procedure in GSM 03.60.

The optional Private Extension contains vendor or operator specific information.

Table 16: Information elements in a PDU Notification Response

Information element

Presence requirement

Reference

Cause

Mandatory

7.9.1

Private Extension

Optional

7.9.26

7.5.14 PDU Notification Reject Request

If the PDP context activation proceeds after the PDU Notification Response, but the PDP context was not established, the SGSN sends a PDU Notification Reject Request message. The Cause value indicates the reason why the PDP Context could not be established:

– ‘MS Not GPRS Responding’

– ‘MS Refuses’.

When receiving the PDU Notification Reject Request message the GGSN may reject or discard the stored T-PDU(s) depending on the PDP type.

After an unsuccessful activation attempt the GSNs may perform some actions to prevent unnecessary enquires to the HLR as described in the section Unsuccessful Network-Requested PDP Context Activation procedure in GSM 03.60.

The TID of the PDU Notification Reject Request message shall be the same as the TID of the PDU Notification Request that triggered the reject.

The End User Address information element contains the PDP type and PDP address of the PDP context that could not be activated.

The optional Private Extension contains vendor or operator specific information.

Table 17: Information elements in a PDU Notification Reject Request

Information element

Presence requirement

Reference

Cause

Mandatory

7.9.1

End User Address

Mandatory

7.9.18

Private Extension

Optional

7.9.26

7.5.15 PDU Notification Reject Response

The message is sent by a GGSN to SGSN as a response of a PDU Notification Reject Request.

Possible Cause values are:

– ‘Request Accepted’

– ‘Mandatory IE incorrect’

– ‘Mandatory IE missing’

– ‘Optional IE incorrect’

– ‘Invalid message format’.

The optional Private Extension contains vendor or operator specific information.

Table 18: Information elements in a PDU Notification Reject Response

Information element

Presence requirement

Reference

Cause

Mandatory

7.9.1

Private Extension

Optional

7.9.26