Cisco Cisco Packet Data Interworking Function (PDIF) Guía Para Resolver Problemas
QoS Management
Dynamic QoS Renegotiation ▀
Cisco ASR 5000 Series Enhanced Feature Configuration Guide ▄
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to the level granted by the HLR. QoS renegotiation is performed by sending an update PDP context request to the
SGSN. This solution is optimal since the appropriate QoS level is always granted to the subscriber without any
requirement on the handset or on the core network. The only prerequisite is QoS renegotiation support on the SGSN. In
this model, over reservation of radio resources is avoided, while maintaining the appropriate bandwidth for subscribers
with real requirements.
SGSN. This solution is optimal since the appropriate QoS level is always granted to the subscriber without any
requirement on the handset or on the core network. The only prerequisite is QoS renegotiation support on the SGSN. In
this model, over reservation of radio resources is avoided, while maintaining the appropriate bandwidth for subscribers
with real requirements.
The ST16 and ASR 5000 supports L7 stateful analysis and QoS Renegotiation. Combining these functionalities results
in Dynamic QoS Renegotiation. The system also generates CDRs (or real time charging information) that includes the
current QoS information and the service accessed. This enables intelligent application-based charging of services, taking
into account the granted QoS. It also enables rebates when it was not possible to provide the QoS level required by an
application.
in Dynamic QoS Renegotiation. The system also generates CDRs (or real time charging information) that includes the
current QoS information and the service accessed. This enables intelligent application-based charging of services, taking
into account the granted QoS. It also enables rebates when it was not possible to provide the QoS level required by an
application.
Important:
For L7 traffic analysis ECSv2 license is required.
QoS Renegotiation for a Subscriber QoS Profile
The following is the overall Dynamic QoS Renegotiation process.
1. When the subscriber attaches to the network, following things happen:
Dampening timer is started for the subscriber.
QoSI is assigned to subscriber. This becomes the QoSC till a re-negotiation occurs, as shown in the
following figure.
The traffic class bit-field is cleared.
2. As the subscriber starts using some applications, the traffic gets classified on the basis of type of data packets or
traffic as mentioned in section Classification of Application Traffic and accordingly the corresponding bit in
Traffic-class-bitfield get set.
Traffic-class-bitfield get set.
3. Following is the mechanics of QoS renegotiation:
Examine traffic-class-bitfield to find out the highest bit that is set. This gives the desired QoS Traffic
Class (QoSD). The associated uplink/downlink peak-data-rate and guaranteed-data-rate values will be
taken from the configured parameters for this traffic class in the subscriber APN. For more
information refer to the Traffic Policing and Shaping chapter.
taken from the configured parameters for this traffic class in the subscriber APN. For more
information refer to the Traffic Policing and Shaping chapter.
If QoSC matches QoSD, no QoS renegotiation is required. Otherwise, it sends an Update PDP Context
Request to the SGSN with the QoSD values and QoS renegotiation starts.
Reset the dampening timer.
The traffic-class-bitfield is cleared.
4. Following are the conditions under which QoS renegotiation happens:
When a higher priority traffic is detected, QoS is renegotiated immediately, without waiting the
dampening times to expire. Thus for example, if the current traffic has a QoS of interactive class and it
detects streaming traffic, it will upgrade the QoS at once to Streaming.
detects streaming traffic, it will upgrade the QoS at once to Streaming.
When system detects lower priority traffic, it waits for the expiry of the dampening timer before
lowering the QoS.
During ―silence‖ or no-traffic, QoS renegotiation requests will not be initiated.
As seen in the following figure, the QoS profile for the subscriber goes through three renegotiations to match
the QoS profile of the (highest priority) application currently being used.
the QoS profile of the (highest priority) application currently being used.