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Gy Interface Support
Quota Behavior
Various forms of quotas are present that can be used to charge the subscriber in an efficient way. Various quota
mechanisms provide the end user with a variety of options to choose from and better handling of quotas for the service
provider.
Time Quotas
The Credit-Control server can send the CC-Time quota for the subscriber during any of the interrogation of client with
it. There are also various mechanisms as discussed below which can be used in conjunction with time quota to derive
variety of methods for customer satisfaction.
Quota Consumption Time: The server can optionally indicate to the client that the quota consumption must be
stopped after a period equal to the "Quota Consumption Time" in which no packets are received or at session
termination, whichever is sooner. The idle period equal to the Quota Consumption Time is included in the
reported usage. The quota is consumed normally during gaps in traffic of duration less than or equal to the
Quota-Consumption-Time. Quota consumption resumes on receipt of a further packet belonging to the service
data flow.
If packets are allowed to flow during a CCR (Update)/CCA exchange, and the Quota-Consumption-Time AVP
value in the provided quota is the same as in the previously provided quota, then the Quota-Consumption-Time
runs normally through this procedure. For example, if 5 seconds of a 10 second QCT timer have passed when a
CCR(U) is triggered, and the CCA(U) returns 2 seconds later, then the QCT timer will expire 3 seconds after
the receipt of the CCA and the remaining unaccounted 5 seconds of usage will be recorded against the new
quota even though no packets were transmitted with the new quota.
A locally configurable default value in the client can be used if the server doesn't send the QCT in the CCA.
Combinational Quota: Discrete-Time-Period (DTP) and Continuous-Time-Period (CTP) defines mechanisms
that extends and generalize the Quota-Consumption-Time for consuming time-quota.
Both DTP and CTP uses a "base-time-interval" that is used to create time-envelopes of quota used.
Instead of consuming the quota linearly, DTP and CTP consumes the granted quota discretely in chunks
Selection of one of this algorithm is based on the "Time-Quota-Mechanism" AVP sent by the server in
Reporting usage can also be controlled by Envelope-Reporting AVP sent by the server in CCA during
Discrete-Time-Period: The base-time-interval defines the length of the Discrete-Time-Period. So each time-
envelope corresponds to exactly one Discrete-Time-Period. So when a traffic is detected, an envelope of size
equal to Base-Time-Interval is created. The traffic is allowed to pass through the time-envelope. Once the
traffic exceeds the base-time-interval another new envelope equal to the base-time-interval is created. This
continues till the quota used exceeds the quota grant or reaches the threshold limit for that quota.
Continuous-Time-Period: Continuous time period mechanism constructs time envelope out of consecutive base-
time intervals in which the traffic occurred up to and including a base time interval which contains no traffic.
Therefore the quota consumption continues within the time envelope, if there was traffic in the previous base
time interval. After an envelope has closed, then the quota consumption resumes only on the first traffic
following the closure of the envelope. The envelope for CTP includes the last base time interval which contains
no traffic.
The size of the envelope is not constant as it was in Parking meter. The end of the envelope can only be
determined retrospectively.
of base-time-interval at the start of the each base-time-interval.
CCA.
the quota grant. Based on the value of this AVP, the usage can be reported either as the usage per
envelope or as usual cumulative usage for that grant.
Cisco ASR 5x00 Packet Data Network Gateway Administration Guide ▄
Features and Terminology ▀
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