What it is
A credentialed Channel takes a finite Unit from a Bucket (the contested availability) and plugs it to a holder (Allocation), with an ephemeral reservation (hold/TTL) and a full lifecycle. EPP’s uniqueness, with real-time contention.
ABP
Allocation Booking Protocol — book the allocation of a scarce seat to a holder, under high contention, without accidental oversell. The shape of EPP, as a contract-first gRPC protocol.
Vocabulary
Repository → Bucket → Unit. Registry is the authority; Channel books;
Allocation is the Unit plugged to a holder; Booking is the aggregate that
carries the FSM (= the Order/cart).
Two axes
A commercial FSM (HELD → CONFIRMED → PAID → FULFILLED → USED) orthogonal to a
per-allocation resolution axis (ANONYMOUS → CONCRETE). The normative form is
the .proto.
Open standard
Spec + proto under Apache-2.0. Anyone can build a conformant server on any stack. The control comes from owning the reference implementation (Reservations), the conformance suite, and operating registries.