Cisco Cisco ASR 5000
Quality of Service (QoS) Management for SGSN
Quality of Service Management ▀
SGSN Administration Guide, StarOS Release 18 ▄
For more information see, 3GPP TS 23.107 (Table 6 “Rules for determining R99 attributes from R97/98 attributes”).
The QoS parameters are sent to GGSN in the Create PDP Context Request. On receiving a Create PDP Context
Response, the QoS sent by GGSN is negotiated with the one sent by SGSN to GGSN. For GPRS access, this negotiated
QoS is sent to the MS in Activate PDP Context Accept.
Response, the QoS sent by GGSN is negotiated with the one sent by SGSN to GGSN. For GPRS access, this negotiated
QoS is sent to the MS in Activate PDP Context Accept.
If the UE requests a subscribed traffic class, the SGSN defaults it to “Interactive” traffic class regardless of the
configuration in the HLR subscription.
configuration in the HLR subscription.
In a UMTS access scenario, the negotiated QoS is sent to RNC in RAB Assignment Request. By default, the SGSN
includes Alternative Max Bit Rate with type set to “Unspecified”. This indicates to the RNC that it can further negotiate
the QoS downwards if either the RNC/UE cannot support the QoS value sent. The RNC may downgrade the QoS based
on its current load/capability and include it in RAB Assignment Response. The SGSN does QoS negotiation once more
with received QoS from the RNC. This is used as the negotiated QoS of PDP context and is sent to the MS in Activate
PDP context Accept. If the RNC has downgraded the QoS, the same will be informed to GGSN by means of an Update
PDP context procedure.
includes Alternative Max Bit Rate with type set to “Unspecified”. This indicates to the RNC that it can further negotiate
the QoS downwards if either the RNC/UE cannot support the QoS value sent. The RNC may downgrade the QoS based
on its current load/capability and include it in RAB Assignment Response. The SGSN does QoS negotiation once more
with received QoS from the RNC. This is used as the negotiated QoS of PDP context and is sent to the MS in Activate
PDP context Accept. If the RNC has downgraded the QoS, the same will be informed to GGSN by means of an Update
PDP context procedure.
QoS Negotiation During a Modification Procedure
The PDP Context Modification procedure can be MS initiated or Network initiated, it is used to change the current
negotiated QoS. If it is a MS initiated PDP Context Modification procedure the QoS negotiation is similar to the QoS
negotiation followed during an Activation procedure. The HLR or GGSN or SGSN (RNC in case of UMTS access) can
perform a Network Initiated QoS modification.
negotiated QoS. If it is a MS initiated PDP Context Modification procedure the QoS negotiation is similar to the QoS
negotiation followed during an Activation procedure. The HLR or GGSN or SGSN (RNC in case of UMTS access) can
perform a Network Initiated QoS modification.
For more information on “PDP Context Modification Procedure” see, 3GPP TS 24.008 section 6.1.3.3
HLR Initiated QoS Modification
The Subscription Information of a Subscriber may change due to the following:
User action (The user may subscribe for a more premium service)
Service provider action (The QoS is restricted on reaching download limits)
This change is relayed by the HLR to the SGSN through the Insert Subscription Data procedure. As per 3GPP TS
23.060 section 6.11.1.1 “Insert Subscriber Data procedure”, the SGSN negotiates the current QoS with new subscribed
QoS and initiates a Network Initiated PDP modification procedure only in case of QoS downgrade. As part of this
procedure, the GGSN (and RNC in case of UMTS access) is updated with the new negotiated QoS followed by the MS.
If a failure occurs or no response is received from the MS for the Modify Request, the PDP context is deactivated.
23.060 section 6.11.1.1 “Insert Subscriber Data procedure”, the SGSN negotiates the current QoS with new subscribed
QoS and initiates a Network Initiated PDP modification procedure only in case of QoS downgrade. As part of this
procedure, the GGSN (and RNC in case of UMTS access) is updated with the new negotiated QoS followed by the MS.
If a failure occurs or no response is received from the MS for the Modify Request, the PDP context is deactivated.
The SGSN is compliant with 3GPP TS 23.060 Release 7 version. The specifications Release 8 and above specify a
modified behavior when the UE is in a IDLE/STANDBY state. If the QoS is modified by the HLR when an UE is an
IDLE/STANDBY state the PDP is de-activated. The SGSN is made compliant with this change to align its behavior
with LTE elements like MME. Therefore the SGSN is compliant with both the Release 7 and Release 8 specifications.
modified behavior when the UE is in a IDLE/STANDBY state. If the QoS is modified by the HLR when an UE is an
IDLE/STANDBY state the PDP is de-activated. The SGSN is made compliant with this change to align its behavior
with LTE elements like MME. Therefore the SGSN is compliant with both the Release 7 and Release 8 specifications.
GGSN Initiated QoS Modification
The GGSN may initiate a QoS Modification Request due to any of the following reasons:
An External Trigger (PCRF)
Current load or capability of the GGSN
If the “No Qos negotiation” flag is set in the previous Tunnel Management Request from SGSN.
The SGSN negotiates this QoS with the subscription. The negotiated Qos is then sent to the UE in a Modify PDP
Request. In an UMTS access scenario, the SGSN updates the new negotiated QoS to the RNC. The new negotiated Qos
is then forwarded to the GGSN in response message.
Request. In an UMTS access scenario, the SGSN updates the new negotiated QoS to the RNC. The new negotiated Qos
is then forwarded to the GGSN in response message.
SGSN Initiated QoS Modification
The SGSN initiated QoS Modification occurs during an Inter-RAT HO (2G to 3G / 3G or 2G), here the negotiated QoS
in new access is different from the negotiated QoS in old access. The SGSN QoS initiated QoS Modification can also
in new access is different from the negotiated QoS in old access. The SGSN QoS initiated QoS Modification can also