Routing User Guide | Defining Routing Rules |
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How Load Balancing Works
When a rule incorporates the balance command, the routing software uses two things to determine which destination receives a given exam: the percentages specified in the rule and internal counters set by the routing software.
When a rule including a balance command is first applied, the routing software begins distributing exams the same way a deck of cards is dealt: the first destination receives one exam, the second destination receives the next exam, and so on. Exams are evenly distributed until the destination with the lowest value specified in the balance command has received its allotted percentage of exams. Then that destination is skipped until the counter resets. Since load balancing is based on percentages, the counter is reset each time 100 exams have been sent.
For example, if a rule specifies…
balance("DEST1"=10%,"DEST2"=40%,"DEST3"=50%)
when MODALITY="CR"
The first 30 CR exams will be distributed evenly, with each destination receiving 10 exams. Once DEST1 has received 10% of the exams, the routing software will skip DEST1 until the counter resets.
The next 60 CR exams are split evenly between DEST2 and DEST3. After this point, DEST2 and DEST3 each have a total of 40 exams. DEST2 now has its allotment of 40 exams, and will be skipped until the counter resets.
The remaining 10 CR exams are sent to DEST3, giving that destination a total of 50 exams.
Once 100 CR exams have been sent, the routing software resets its counters to zero, and starts distributing exams to all three destinations again.
Note that a destination receiving a comparatively smaller percentage of exams will become idle more often than destinations that receive a greater percentage of exams.
Resetting the Load Balancing Counter
When routing rules are imported, the counters used for load balancing are all reset to zero. You can take advantage of this trait if you need to
April 2006 | VistA Imaging V. 3.0, Patch 18 | 13 |