Cisco Cisco ASR 5000
Quality of Service (QoS) Management for SGSN
▀ Quality of Service Management
▄ SGSN Administration Guide, StarOS Release 18
occur during a new SGSN ISRAU/SRNS procedure where the new negotiated QoS is different from the negotiated QoS
received from the peer SGSN.
received from the peer SGSN.
Whenever a UE performs an Intra or Inter SGSN HO, the SGSN receives the requested QoS, subscribed QoS and the
negotiated QoS from the old access (during Intra SGSN HO ) or from peer SGSN (during Inter SGSN HO). This
requested QoS is then negotiated with the subscribed QoS. If the negotiated QoS is different from the received
negotiated QoS, the SGSN initiates a network initiated QoS modification procedure to update the new negotiated QoS
to the UE after completing the HO procedure.
negotiated QoS from the old access (during Intra SGSN HO ) or from peer SGSN (during Inter SGSN HO). This
requested QoS is then negotiated with the subscribed QoS. If the negotiated QoS is different from the received
negotiated QoS, the SGSN initiates a network initiated QoS modification procedure to update the new negotiated QoS
to the UE after completing the HO procedure.
RNC Initiated QoS Modification (UMTS access only)
In a RNC initiated QoS modification procedure the SGSN negotiates the QoS with the current negotiated QoS. In case
of a downgrade, the SGSN updates the GGSN and MS with the new negotiated QoS.
of a downgrade, the SGSN updates the GGSN and MS with the new negotiated QoS.
For more information see, 3GPP TS 23.060 section 9.2.3.6 on “RAN-initiated RAB Modification Procedure”
No QoS Negotiation Flag
When the ‘No QoS Negotiation’ flag is set, the SGSN indicates to the GGSN not to negotiate the QoS. The “No QoS
Negotiation” flag is set in the following scenarios:
Negotiation” flag is set in the following scenarios:
While sending Update PDP Context request during activation (Direct tunnel).
During a service request for data with direct tunnel enabled for the subscriber, a UPCQ is initiated to inform the
GGSN with the teid and the address of the RNC. This Update PDP context request has no negotiation bit set.
Update PDP context request sent during preservation procedures.
UPCQ sent to indicate establishment / removal of direct tunnel.
Intra SGSN SRNS.
Downlink data for the subscriber without active RABs and direct tunnel enabled for the subscriber, UPCQ is
initiated to inform the GGSN of the teid and the address of the RNC. This Update PDP context request has “No
QoS Negotiation” flag set.
QoS Negotiation” flag set.
In all modification procedures (HLR,RNC,MS) if any other node other than the modifying entity has
downgraded the QoS. For example, consider a HLR Initiated Modification procedure where the SGSN does the
following signalling:
following signalling:
Initiates a UPCQ to inform the GGSN of the QOS change, GGSN sends a UPCR with same QOS as
UPCQ.
Modify PDP context Request to MS, the MS sends a Modify PDP Accept.
RAB establishment request to the RNC, the RNC downgrades the QoS in the RAB assignment
response.
The SGSN initiates a UPCQ to inform the GGSN of the new QoS sent in the previous step. This UPCQ
will have no QoS negotiation bit set.
If loss of Radio connectivity feature is enabled, then the Update PDP Context initiated to inform the GGSN that
the MS is back in Radio Coverage will have the “No Qos Negotiation” bit set.
QoS Features
Traffic Policing
The SGSN can police uplink and downlink traffic according to predefined QoS negotiated limits fixed on the basis of
individual contexts - either primary or secondary. The SGSN employs the Two Rate Three Color Marker (RFC2698)
individual contexts - either primary or secondary. The SGSN employs the Two Rate Three Color Marker (RFC2698)