Vista Imaging Vista Routing - Manual (Page 21)

Routing User Guide Defining Routing Rules
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"
ƒ 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.
ƒ 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.
ƒ The remaining 10 CR exams are sent to
DEST3 , giving that destination a total of 50
exams.
ƒ 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 fine-tune or troubleshoot
situations where load balancing is used. Note that it is not necessary to change routing
rules to achieve this; you only need to re-import them.
April 2006 VistA Imaging V. 3.0, Patch 18 13