Update PDP Context Request

These messages are sent from the GGSN to the controller or vice versa. In case of a GGSN initiated request, the change in data plane IP address at GGSN handled by the controller.

In case of a controller initiated request, the change in data plane IP address at the controller is sent to the GGSN. The table below lists the message attributes.
Table 1. Update PDP context request attributes
Attribute Presence Type Description
Flags
  • Version
  • Protocol type
  • Spare bit
  • Extension header
  • Sequence number
  • N-PDU flag
M
  • Version - 1
  • PT - GTP (1)
  • Spare bit- 0
  • E - 0
  • S - 1
  • PN - 0
  • Version - Determines the version of the GTP protocol
  • Protocol type - Protocol discriminator between GTP (when PT is “1”) and GTP' (when PT is “0”)
  • Extension header - Indicates the presence of a meaningful value of the next extension header
  • Sequence number - Value of the sequence number
Common Flags O Octet The common flags information element holds values for multiple bit flags. The controller sets only bit 7 (Upgrade QoS Supported). All other bits are set to zero.
Message Type M Integer Message type value is 18.
Length M Integer This attribute indicates the payload length in octets.
TEID M Integer This attribute identifies a tunnel endpoint in the receiving GTP-U or GTP-C protocol entity.
Sequence number O Integer This attribute is used as a transaction identity for signaling messages having a response message defined for a request message. This is the sequence number value, which is copied from the request to the response message header.
N-PDU number O Integer This attribute is used at the inter SGSN routing area update procedure and in the inter-system handover procedures.
IMSI C Integer This attribute is the subscriber identity of the user equipment.
Recovery O Integer This attribute indicates if the peer GSN restarts. The value should be same as the values in the messages received from GGSN. This value is incremented and sent by the controller when restarted.
TEID Data I M Integer This indicates the tunnel endpoint Identifier for data transmission, which is requested by the receiver of the message flow.
TEID Control Plane C Integer This indicates the tunnel endpoint identifier for the control plane. This attribute should be present, if the SGSN has not confirmed successful assignment of its Tunnel Endpoint Identifier control plane to the peer GGSN.
NSAPI M Integer For the controller initiated message, this attribute is a configurable value in flat file. The value ranges from 5-15.
Protocol Configuration O Integer This attribute is used with IP PDP type.
GSN Address M Integer This attribute is the controller address used for signaling.
GSN Address M Integer This attribute is the controller address use for user traffic.
Quality of Service M Integer The purpose of the quality of service information element is to specify the QoS parameters for a PDP context.
RAT Type O Integer This attribute value is always set to 3(IWLAN) in case the messages are initiated by the controller.
Error Indication O Integer These messages are sent from the GGSN to the controller. Error Indication lists the message attribute.