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Overview

In prior releases, the SBC Core acquired and released licenses in blocks (default value 25) in response to the call rate. The SBC now uses a demand-based algorithm called Dynamic Rate Based Algorithm to make the license allocation more effective and efficient. The Dynamic Rate Based Algorithm allocates licenses based on the recent history of the call rate. As the call rate increases, the SBC requests more licenses and temporarily admits more calls than it holds licenses for, while those license requests are outstanding. As the call rate decreases, the SBC releases licenses, but more slowly than it acquired them, so that brief drops in the call rate do not cause licenses to be released.

The grace license timers start at the time when the release or acquire message pair is logged for each license. This can take a while, as refresh requests are made, time out, and are retried, until SBC finally puts each license into grace period. The grace license cache is maintained separately for each CE. Licenses in grace period are not released when the call load drops.

Dynamic Rate Based Algorithm Parameters

The Dynamic Rate Based Algorithm parameters are customizable. Contact the Sonus Support team for more information.

Table : Demand Based Algorithm Parameters

FieldDescription
NmaxMonitoring interval, default 15 secs, to trigger SLS request. The license usage is monitored for this period to trigger SLS license requests for any updates up or down.
NminRate check interval, default 3 secs. An early SLS request can be made at this interval to adapt to spikes within Nmax period.
Low usage limitA limit used to help adjust the algorithm by adjusting Rate factor for low license usage Cases-See Rate factor.
RF-Rate factor

This is a usage factor to trigger an early SLS request. Default is 60% of the peak usage during the past Nmax period. Rate factor will be halved if there is surge in usage like initial ramp up, or when current session count is less than a low usage limit (default 10).

AF- Allowance factorBuffer requested on top of the calculated count requested, default 10%.

Implementation

The Dynamic Rate Based Algorithm is implemented as follows:

  1. NRM shares current counts for all counted licenses to the License mgr(LM) in SM for each call using shared memory.
  2. LM Client thread will have a periodic timer for the sampling interval -1 sec.
  3. For each Sampling Interval, LM puts the counts for all the counted features in a circular list of size Nmax.
  4. For each Nmin interval LM calculates the latest peak for each feature during past Nmax period.

    Check if the latest peak > current licenses and (latest peak – current licenses) or current licenses * 100 > rate factor RF – trigger SLS request early. Go to step 6.

  5. For each Nmax interval LM calculates the latest peak usage for each feature during past Nmax period.

    1. Increasing usage: Check if the latest peak > current licenses. If so trigger SLS request for latest peak count for the feature.

    2. Decreasing usage: Check if the latest peak + allowance < current licenses. If so trigger SLS request for latest peak count for the feature.

    3. Nmax, Nmin intervals restarted.

  6. SLS request latest peak count for the feature. The Nmin period is restarted.

Status Command Examples

To view the license information:

Example
show table system licenseInfo
FEATURE NAME  ID       EXPIRATION DATE   LIMIT  SOURCE   USE
--------------------------------------------------------------
SRTP          0000                       0               0
ENCRYPT       0000                       0               0
SBC-RTU       0000     2018-12-31-05:00  34     Network  10
DSP-EVRC      0000                       0               0
DSP-G722      0000                       0               0
POL-BASE      0000                       1      BuiltIn  0
SBC-MSRP      0000                       0               0
VDSP-RTU      0000     2018-12-31-05:00  34     Network  0
DSP-AMRNB     0000                       0               0
DSP-AMRWB     0000                       0               0
SBC-SIP-I     0000                       0               0
SBC-VIDEO     0000                       0               0
SBC-4X1GMP    0000                       0               0
SBC-SIP323    0000                       0               0
SBC-SIPREC    0000                       0               0
SBC-1X10GMP   0000                       0               0
SBC-POL-RTU   0000     2018-12-31-05:00  34     Network  10
SBC-POL-E911  0000                       0               0
SBC-POL-ENUM  0000                       0               0
SWE-INSTANCE  0000     2018-12-31-05:00  1      Network  0
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To view the SBC switchover synchronization status:

Example
show status system syncStatus
syncStatus "Policy Data" {
    status syncCompleted;
}
syncStatus "Configuration Data" {
    status syncCompleted;
}
syncStatus "Call/Registration Data" {
    status syncCompleted;
}
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