1. Feature Guide
  2. DSR Features and Functions
  3. Routing and Transaction Related Parameters in the DSR
  4. Congestion Control
  5. Diameter Overload Indication Conveyance
  6. Traffic Throttle Point

2.6.15.10.6 Traffic Throttle Point

A logical Traffic Throttle Point (TTP) is required to manage the DOIC relationship between the DSR and the Reporting Nodes. Some of the major items in the TTP include:

  • DOIC scope for the TTP: HostID/AppID pair.
  • Configuration parameters for the TTP.
  • Tracks the rate information per color/priority.
  • Tracks the administrative, operational and a throttling status (enabled/disabled, current abatement requests, so on).

The table below lists the data the TTP contains. The configuration data that is common between TTPs has been split out into a separate table shown below:

Table 2-7 TTP Data Components by Type

Type of Data Data Values Displayed? Mandatory Default Comments
Scope Entity Type HostID Y Y N/A  
  Entity Name HostID Y Y N/A  
  AppID AppID name Y Y N/A  
Configuration See the table below Choice list of Congestion Configuration Sets Y N System Default  
  Maximum ETR ETR value in Messages per Second Y Y N/A The maximum ETR allowed for the TTP in the absence of DOIC abatement. This field is mandatory since it is used as part of the calculation for TTG loss %. Note that this is ETR (requests only), not EMR (requests and answers).
  Alternate Implicit Route Valid Route List on the DSR Y N Blank An optional Route List which specifies an alternate route (list) to use when “implicit routing” is invoked and the primary route to the Host is unavailable. The TTP Alternate Implicit Route List is higher priority (that is is used instead of) any Alternate Implicit Route List defined at the Peer level.
  Maximum Loss % Threshold 0-100% Y Y 100% If the current loss rate for the TTP is greater than or equal to this number, routing should “skip” this TTP, and take whatever the next routing action is (that is treat it just like it didn’t meet the “minimum weight” requirements for a Route List). A default of 100% mimics the current DSR behavior (that is ignores DOIC loss data).
Status

Throttling

Admin State

 Enabled/Disabled Y   Disabled This admin state controls the overall throttling status of the TTP. When it is disabled, no throttling is done. When it is enabled, the TTP will at least do static throttling if the EMR value is defined. Whether the TTP also does “DOIC” dynamic throttling is set by the Dynamic Throttling Admin State.
 

Dynamic Throttling

Admin State

         This admin state controls whether the TTP also performing DOIC throttling. When it is enabled the TTP will send DCA AVPs to the peer, and look for OLR AVPs in answers. It will also comply with any loss requests. When it is disabled the TTP will only do static throttling.
  Operational State Available, Degraded, Inactive Y N/A N/A This state is driven by a number of factors such as the current loss % (that is is the TTP degraded), and the operational status of the underlying peer.
  Operational State Reason (similar to the existing ETG states) Y N/A N/A This is the reason for the operations state. For instance, when in the degraded mode the operational reason could be Peer Overload, or static rate Exceeded. When in the Inactive state the reason could be TTP disabled or SMS service degraded.
  Current Abatement Algorithm Loss, Rate, or NA Y N/A N/A Note that this is only set while the DSR is in an overload state. Otherwise it will be set to Not Applicable (NA).
Current DOIC Status Normal, Overload, Recovering Y N/A N/A
  • Normal means no overload condition.
  • Overload means that the Current Time to Expire is greater than 0
  • Recovering means that the DSR is ramping up the traffic after an overload state has ended.
 Current DOIC Status.
Current Time to Expire Time in seconds Y N/A N/A If this is non-zero then the DSR is in an active DOIC Overload Control State (OCS) requested by the DOIC Reporting Node. The DSR moves from the “Overload” to the “Recovering” state when either this timer expires, or the Host sends a time of "0". Time is shown in seconds since it can only be set in seconds. Current Time to Expire.
Current Loss Rate 0-100% loss Y N/A N/A From the OC-OLR when using the Loss abatement algorithm. Current Loss Rate.
Priority 1/Color 1 OTR OTR in messages per second N N/A N/A Offered Transaction Rate (OTR) not EMR since these are requests only. There’s no need to display the breakdown of rate by color/priority. Priority 1/Color 1 OTR.
…..   N N/A N/A   …..
Priority X/Color X OTR OTR in Messages per Second N N/A N/A   Priority X/Color X OTR.
Total OTR OTR in Messages per Second Y N/A N/A Only the total across the different Colors or Priorities needs to be displayed. Total OTR
Target ETR ETR in Messages per Second Y N/A N/A The current Max Egress Target Transaction Rate. Normally this is the configured Max ETR for this TTP. But this number is reduced to reflect the current loss rate during overload. Target ETR
Percentage of Transactions Diverted 0-100% Y N/A N/A The percentage of the OTR for this TTP that’s being diverted due to overload. Percentage of Transactions Diverted.

The following table shows the items in the TTP configuration set:

Table 2-8 TTP Configuration Set Components

Type of Data Data Values Displayed? Mandatory Default Comments
Scope Configuration Set Name Customer Defined Y Y N/A The text string name for this configuration set.
Configuration Abatement Recovery Rate 1-100%/second Y Y 5%/Sec The rate at which the DSR goes from the requested loss to zero abatement after an OLR expires. If the current requested loss is -20%, then the DSR decreases the loss linearly from -20 % to 0 at this rate.
Supported Abatement Algorithms Loss Y Y Loss This is the list of abatement algorithms sent in the OC-feature-vector to the Reporting Node. It is configured at the TTP configuration set level since the customer may not want to allow all of the supported algorithms on a given TTP.
Default OC-Validity-Duration 0-86,400 seconds Y Y 30 seconds This is the default time for the OC-Validity if a time isn’t specified in an OLR. Note that 0 in an OLR means stop abating. The suggested default here of 30 seconds is from the DOIC spec.
Rate Convergence Time 250-2000ms Y Y 1000ms This parameter controls the sensitivity of the calculated rate to bursts of traffic on the TTP. The ETR calculated by the Sliding Historic Metric is always normalized to 1 second (as per the DOIC spec), but the DOIC specification specifically allows for the rate to be higher within that second as long as the per-second average is maintained.
Dynamic Throttling Override Message Priority Threshold Priority 1-2 N N N/A Messages with this priority or higher will be routed at the TTP level even if routing them will cause the TTP to exceed a requested abatement level, as long as the message rate is below the TTP Static Throttle Rate. A priority of 0 is not allowed since then the flag effectively disables DOIC dynamic throttling.