For this client we are using 3 Routing Server (URS) High Availability pairs with load balancing through Load Distribution Server (LDS).
During volume testing this week we noticed a problem where calls we being delivered twice to the same advisor using both line 1 and line 2 on their stations.
The URS 7.6 deployment guide describes this possibility in a section on “Router Self-Awareness”:
Starting with 7.6, you can configure URSs, such as those in a loading balancing scenario, to share routing information between themselves by setting a mode called Router Self-Awareness. If Router Self-Awareness is activated for the participating URSs, then the number of calls in transition sent to this target will include calls in transition sent by all URSs participating in the same Router Self-Awareness group.
Using Router Self-Awareness, URSs deployed in a load sharing mode can communicate with each other regarding selected targets and target statistics. This addresses potential load balancing issues across multiple URSs. It also addresses certain race (timing) conditions that can occur in agent-based routing.
When Router Self-Awareness mode is configured, URSs can exchange internal data in order to have more real time information on their working environment. In addition to information about any URS decision to send a call to some destination, information in the communication channel between URSs can also be used for:
- Agent blocking. If Router Self-Awareness is on, then every URS will block the agent for routing as soon it receive notification that an agent is selected by some other URS. The assumption here is that other URS’s notification can arrive much sooner than the agent will be reported as busy by Stat Server. This can save URS from the necessity to doing a reserving request that will unconditionally fail.
- Preventing other URSs from selecting the same targets (Agents, Places) during the early phase of routing before the agent reservation mechanism detects the call.
To configure “Router Self-Awareness” the following steps are required:
- Add a dedicated HA “Notification” Message Server Pair
- On the Annex of the Message Server application add a “__ROUTER__” section with the options set as shown below
- On each URS add a connection to the primary “Notification” Message Server