novox/hq 04-ISSUES/107. A declaration's only identity was the digest of
its bytes: a host could say "not the last" and could not say "older". On
the link, nothing refused an older one at all, and the drain picked the
last to arrive — wrong exactly when it mattered, a backlog drained out of
order or a broker that split a burst.
A declaration may now carry a sequence, one higher per send. A host
refuses one lower than what it kept, whole, and says why. The drain keeps
the highest sequence in a batch rather than the last to arrive.
Only when both sides claim an order. Absent reads as zero — "no ordering
claimed", not "first" — so a controller that sends none is still
understood and a host that kept one before it understood them compares
nothing. That is what lets hosts go first and the controller follow, which
is the order 087 says a new field needs.
jschoubben
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