Непонятка с простеньким алгоритмом

Есть такой вот абзац в rfc2782 (A DNS RR for specifying the location of services):

Compute the sum of the weights of those RRs, and with each RR
associate the running sum in the selected order. Then choose a
uniform random number between 0 and the sum computed
(inclusive), and select the RR whose running sum value is the
first in the selected order which is greater than or equal to
the random number selected. The target host specified in the
selected SRV RR is the next one to be contacted by the client.
Remove this SRV RR from the set of the unordered SRV RRs and
apply the described algorithm to the unordered SRV RRs to select
the next target host. Continue the ordering process until there
are no unordered SRV RRs. This process is repeated for each
Priority.

Мне непонятно здесь первое предложение, например, есть элементы 0, 1, 15, 5, какие именно суммы надо ассоциировать с каждым элементом?

Помогите расковырять.