| User Data Repository Diameter User's Guide Release 12.4 E92984-01 |
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Egress Throttle Lists are collections of two or three Egress Throttle Groups, where each of those Egress Throttle Groups is configured on a different diameter routing systems. Egress Throttle Lists are used to implement Coordinated Egress Throttling across Multiple diameter routing systems. Egress Throttle Lists aggregate Egress Message Rate and Pending Transaction data from the component Egress Throttle Groups and use the aggregated metrics to throttle Requests to the component ETGs' peer nodes and connections.
Egress Throttle Lists have a similar data structure to Egress Throttle Groups. Both can track Egress Message Rate and Pending Transactions independently. Both have the same set of Onset and Abatement Thresholds for EMR and EPT, which are calculated from associated ETL Rate and Pending Transaction Limiting Configuration Sets.
The primary difference between Egress Throttle Lists and Egress Throttle Groups is that ETLs are provisioned at the NOAM level, while ETGs are provisioned at the SOAM level. Egress Throttle Groups are enabled and disabled with a maintenance GUI on the SOAM, but Egress Throttle Lists do not have an associated maintenance screen in a GUI. Egress Throttle Lists are enabled and disabled on a diameter signaling router by provisioning and maintenance actions against the component ETGs.
ETL Message Rate Limiting is controlled by the settings for the component ETGs, as described in Rate Limiting Configuration Sets and Diameter Maintenance Egress Throttle Groups. ETL Pending Transaction Limiting is controlled by the settings for the component ETGs, as described in Pending Transaction Limiting Configuration Sets and Diameter Maintenance Egress Throttle Groups.
Egress Throttle List Maintenance
Egress Throttle Lists perform two functions: rate limiting and pending transaction limiting. Each of the functions is independent of one another and can be optionally configured and controlled separately. Egress Throttle Lists does not have an associated GUI maintenance page to control whether Egress Message Rate Limiting and Egress Pending Transaction Rate Limiting are enabled or disabled. EMR and EPT Limiting for the ETL are controlled by maintenance changes to the ETL's component ETGs.
Because an Egress Throttle List is composed of Egress Throttle Groups provisioned on different routers, an Egress Throttle List instance on an MP has additional state data that an Egress Throttle Group does not have. This data is the number of SMS-controlled ComAgent connections between the local diameter router server and the other diameter router servers with Egress Throttle Groups in the Egress Throttle List. If the local diameter router server is connected to all other diameter router servers with ETGs in the ETL, the Egress Message Rate and Pending Transaction thresholds are based on values calculated from the associated ETL Rate and Pending Transaction Limiting Configuration Sets. But if the local diameter router server is not connected to all diameter router servers with ETGs in the ETL, the Egress Message Rate and Pending Transaction thresholds are reduced according to the Per SMS Connection Failure Percent Reduction parameter provisioned against the ETL on the local diameter signaling router.
The following is an example of the reduced EMR and EPT thresholds due to a connectivity failure with another diameter router server that has an ETG contained in an ETL. Assume that the ETL contains two ETGs in two different diameter router servers. The maximum rate for the ETL is 10,000 messages per second, and the maximum number of pending transactions is 12,000. The per-connection percent reduction value for each ETG is 50, which means that the maximum values of EMR and EPT should be reduced 50 percent if a diameter server router cannot connect to the other diameter signaling router to exchange aggregated data for the ETL. In this example, if one of the diameter signaling router cannot connect with the other, it uses 5,000 messages per second for the maximum EMR for the ETL, and it uses 6,000 transactions as the maximum EPT. The rate and pending transaction onset and abatement thresholds are calculated from these reduced maximums for as long as the diameter signaling router is not able to connect to the other diameter signaling router.
