1. Feature Guide
  2. DSR Features and Functions
  3. Routing and Transaction Related Parameters in the DSR
  4. Congestion Control
  5. Per Connection Egress MPS Control

2.6.15.5 Per Connection Egress MPS Control

The Egress Message Throttling feature provides a mechanism that assists with the prevention of Diameter peer overload. It does so by allowing the user to configure the max Egress Message Rate (EMR) on a per connection basis and shedding messages as the offered message rate gets closer to the max EMR. The feature works in conjunction with the message prioritization infrastructure and provides intelligent load shedding based on the volume of the offered load. The load shedding is performed by dropping requests based on priority and the offered Message Rate. It should be noted that message priorities are assigned using DRMP AVP when DRMP feature is enabled or through MPCS configurations.

The connection egress message throttling behavior is governed by user-configurable Egress Message Throttling Configuration Sets. Each Egress Message Throttling Configuration Set contains:

  • A maximum allowed EMR.
  • A minimum of one and up to a maximum of three pairs of user-configurable EMR Throttle and Abatement Thresholds (TT & AT) expressed as % of max EMR.
  • Convergence Rate: The time the algorithm takes for the measured rate to converge on the actual rate. Useful for bursty traffic.
  • Abatement Time

The “maximum allowed EMR” dictates the maximum volume of traffic that can be served over a particular connection. Each EMR throttle & abatement threshold pair are then expressed as percentages of the maximum allowed EMR and dictate how the connection congestion state will be updated.

The DSR allows for egress message throttling to be enabled for at least 500 peer connections in a single DSR NE. To enable egress message throttling on a connection, the user creates an Egress Message Throttling Configuration Set and assigns it to one or more DSR peer connections that are to be throttled using the configuration set settings. The DSR supports at least 50 user-configurable Egress Message Throttling Configuration Sets.