1. Feature Guide
  2. DSR Features and Functions
  3. Routing and Transaction Related Parameters in the DSR
  4. Congestion Control
  5. Egress Throttle Group (ETG) Limiting

2.6.15.6 Egress Throttle Group (ETG) Limiting

Network operators cannot control the ingress load-shedding behavior of all nodes in their networks and many become unstable and fail when offered excessive ingress traffic loads. Therefore, DSR can be utilized to enforce maximum egress traffic rates and maximum pending transaction counts on a connection, a peer, or an aggregate group of connections/peers.

  • Egress Throttle Group Rate Limiting: A method to control the total egress Request traffic rate that DSR can route to a user-defined group of connections or peers.
  • Egress Throttle Group Pending Transaction Limiting: A method to control the total number of transactions that DSR can allow to be pending for a user-defined group of connections or peers.
DSR supports two modes of ETG limiting:
  • Threshold Throttling Mode: DSR limits the diameter requests or pending transactions for a given ETG based on user-defined onset and abatement thresholds set for ETG’s rate congestion level (ETG-RCL), values: CL1, CL2 and CL3. This mode can only be used when 16 Message Priorities is disabled.
  • Limit Throttling Mode: DSR performs throttling by measuring the rate of Request messages offered to each ETG and divert the traffic based on configured Congestion Discard Policy when request rate or pending transaction exceeds the user-defined maximum traffic allowed. This method eliminates congestion levels and the need for the user-defined congestion level onset and abatement thresholds. This mode can be used with both legacy 5 message priorities and 16 message priorities.
These features provide DSR egress throttling capability that allows the user to:
  • Configure an ETG with a max of 128 entries, each peer/connection can be in only 1 ETG.
  • Identify a group of peers and/or connections and associate them with an Egress Throttle Group.
  • Set the ETG’s maximum egress Request rate.
  • Configure throttling and abatement thresholds or maximum allowed ETG request rate and pending transactions based on ETG limiting mode.
  • Set convergence rate and abatement timer.
  • Set the ETG’s maximum pending transaction limit.