Section: 6.1.3.3.2 MS initiated PDP Context Modification accepted by the network
Content: In order to initiate the procedure, the MS sends the MODIFY PDP CONTEXT REQUEST message to the network, enters the state PDP-MODIFY-PENDING and starts timer T3381. The message may contain the requested new QoS and/or the TFT and the requested LLC SAPI (used in A/Gb mode). If the selected Bearer Control Mode is 'MS/NW' and the MS wants to modify the QoS, it shall include a TFT with packet filter(s), or if no packet filters are proposed to be either added, replaced or deleted, it shall set TFT operation code to "No TFT operation" and include packet filter identifier(s) in the Packet filter identifier parameter in the parameters list to indicate which packet filter(s) in the TFT is associated with the QoS change. If the TFT information element is included in the MODIFY PDP CONTEXT REQUEST message and packet filters are proposed to be added, the MS shall allocate packet filter identifier(s) for all packet filters to be added to the TFT. The MS shall allocate packet filter identifier value s which are currently not allocated to any existing packet filter of the TFT. If a PDP context is associated with a TFT containing packet filters established by both the MS and the network, the only parameters in the QoS profile of that PDP context the MS is allowed to modify are the bitrate parameters. Upon receipt of the MODIFY PDP CONTEXT REQUEST message, the network may reply with the MODIFY PDP CONTEXT ACCEPT message in order to accept the context modification. The reply message may contain the negotiated QoS and the radio priority level based on the new QoS profile and the negotiated LLC SAPI that shall be used in A/Gb mode by the logical link. Upon receipt of the MODIFY PDP CONTEXT ACCEPT message, the MS shall stop the timer T3381. If the offered QoS parameters received from the network differs from the QoS requested by the MS, the MS shall either accept the negotiated QoS or initiate the PDP context deactivation procedure. If a modification of QoS is requested by the MS, which the network can not accept, being unable to provide the requested QoS, it should maintain the QoS negotiated as previously negotiated or propose a new QoS. That means that the network should not reject the MS initiated PDP context modification request due to the unavailability of the QoS. If the MS requested a value for a QoS parameter that is not within the range specified by 3GPP TS 23.107[ Quality of Service (QoS) concept and architecture ] [81], the network should negotiate the parameter to a value that lies within the specified range.