2.6.15.7 Coordinated Egress Throttling Across Multiple DSRs

When multiple DSRs (mated pair or triplet) connect to common servers, there is a need for the DSRs to share egress throttling information to avoid under-utilization or overload of the common servers in load share or failure scenarios. This feature allows multiple DSRs to share real-time Egress Throttle Group Rate and Pending Transaction information in order to maximize utilization of servers common to the DSRs while also protecting the common servers from overload.

To address communication failure amongst the contributing DSRs when under coordinated egress throttling, DSR supports a user configuration option that specifies how much the coordinated ETGs Rate and/or Pending Transaction Limit should be reduced from the coordinated maximum egress rate and pending transaction value. This user configurable option ‘Coordination Failure (% Reduction)’ affects egress Request rate and pending transaction maximum value proportional to the number of peer DSR communication failures. Also, please note that this ‘Coordination Failure (% Reduction)’ parameter does not apply when a DSR is providing SOAM managed single DSR scoped egress throttling.

Figure 2-23 2 DSR Sites- Coordinated Egress Throttling Example