# Service classes > DESP classes A, B, and C above Grid 1 Firm, curtailment order C then B then A, Firm/Semi-Firm/Flex aliases, and per-interval reclassification. - Repository: g2tf-org/g2tf-standards - GitHub: https://github.com/g2tf-org/g2tf-standards - Human docs: https://grok-wiki.com/public/docs/g2tf-org-g2tf-standards-436ba3f3e0ff - Complete Markdown: https://grok-wiki.com/public/docs/g2tf-org-g2tf-standards-436ba3f3e0ff/llms-full.txt ## Source Files - `specs/desp/spec.md` - `specs/gcap/spec.md` - `specs/g2p/spec.md` - `members/use.md` - `rfcs/grid-2-rfc-1.pdf` --- --- title: "Service classes" description: "DESP classes A, B, and C above Grid 1 Firm, curtailment order C then B then A, Firm/Semi-Firm/Flex aliases, and per-interval reclassification." --- DESP (`specs/desp/spec.md`, version **26.0-draft**) is the Grid 2 service-class taxonomy. Use Members advertise one signed consume position per class in a G2P Service Descriptor; GCAP Allocators MUST honor class order when constraints bind; Traditional Firm (Grid 1) sits outside the overlay and is never cut by GCAP. ## Class stack Grid 2 stratifies demand **above** the existing firm layer. Classes **A**, **B**, and **C** together are traditional non-firm demand (RFC #1, Figure 2). ```text Grid 1 Traditional Firm served under existing firm service ──────────────────────────────────────────────────────────── Grid 2 A Assured highest non-firm curtailed last B Preferred middle curtailed after C, before A C Best Efforts lowest curtailed first ──────────────────────────────────────────────────────────── Buffer committed dispatch clears BEFORE any A/B/C cut ``` | Class | Canonical name | Position | Semantics | |---|---|---|---| | — | Traditional Firm (Grid 1) | Base | Outside Grid 2. Served per existing firm service. **Never curtailed by GCAP.** | | **A** | Assured | Highest non-firm | Curtailed last among Grid 2 classes. Latency-sensitive, hard-to-defer demand. | | **B** | Preferred | Middle | Curtailed after C, before A. Deferrable-with-constraints demand. | | **C** | Best Efforts | Lowest | Curtailed first. Unmet or deferred most often. Statistical-multiplexing tier. | Naming is not closed. RFC #1 Protocol Interactions uses **Firm / Semi-Firm / Flex** for the three Use positions. DESP maps those aliases to **A / B / C**. Reconciliation of Assured/Preferred/Best-Efforts vs. Firm/Semi-Firm/Flex is an explicit DESP open item. Implement against letter codes **A**, **B**, **C** until the living spec settles names. | RFC #1 / interaction-table alias | DESP letter | DESP name | |---|---|---| | Firm | A | Assured | | Semi-Firm | B | Preferred | | Flex | C | Best Efforts | Do not confuse the **Firm** alias for Class A with **Traditional Firm (Grid 1)**. The latter is not a DESP class and is not a G2P Use position. ## Normative ordering When GCAP still needs relief after headroom and Buffer dispatch, it ramps down Use allocations in this order only: 1. **C** Best Efforts first 2. **B** Preferred next 3. **A** Assured last 4. **Traditional Firm (Grid 1)** is never touched Additional MUSTS from DESP §2 and GCAP §3: - Class ordering for curtailment MUST be **C → B → A**. - Buffer **committed dispatch** MUST clear **before any class is curtailed**. - Within a class, curtailment MUST be **proportional** (connection size and differential request size). The exact weighting formula is still open in GCAP §7. - Allocations apply to the **coming one-minute interval only** and expire with it. Buffers are not A/B/C. A Buffer offers signed charge (+) / discharge (−) and receives **committed dispatch**, not per-class commit-%. Sources in v26.0 offer a single **committed take**; mirrored A/B/C on supply is an open item on the Source Member spec. ## What travels on the wire (logical) G2P carries the taxonomy; it does not define it. Wire format is unspecified. **Use → Allocator** — Service Descriptor (`G2P` §3.1) One signed position per DESP class over a forward time vector. Units are energy in the interval (v26.0 scope). Positions MAY change when the descriptor is reissued. Classes MAY change per interval (DESP dynamic reclassification). **Allocator → Use** — Commitment (`G2P` §3.2) Per-class allocation for the coming interval. Identifies interval, domain, and clearing-inputs version. Not classed A/B/C in v26.0. Buffer dispatch is step 2 of GCAP, before any load cut. **Use → Allocator** — Response / Telemetry (`G2P` §3.4) Members MUST report **actual per-class dispatch** against the Commitment (verified self-dispatch). ```mermaid sequenceDiagram participant Use as Use Member participant G2P as G2P participant Alloc as Allocator (GCAP) Use->>G2P: Service Descriptor
signed +A +B +C (energy / interval) G2P->>Alloc: in-zone descriptors Note over Alloc: 1 headroom
2 Buffer dispatch
3 cut C then B then A
never Grid 1 Firm Alloc->>G2P: Commitment
per-class commit-% G2P->>Use: commit-% for coming minute Use->>G2P: per-class verified self-dispatch ``` ## Per-interval reclassification Classification is **dynamic**. A Member MAY reclassify request buckets **each interval**. The Use Member owns how internal workloads land on A/B/C. The Allocator never sees or directs facility internals; it clears **class-level positions only**. Broadcast a G2P Service Descriptor: one signed `request to consume (+)` per class over the forward time vector. Reissue the descriptor if the mix changes. Self-dispatch within that interval's commit-% and agreed host-utility ramp rates. Report verified per-class dispatch. Revert to the Grid 1 baseline (firm load limit) or manual curtailment. Fallback is locally determinable; it MUST NOT depend on a remote peer. Reclassification does not change GCAP order. Moving energy from C into A raises that bucket's protection only for intervals where the new descriptor is cleared. There is no specified carry of unmet Class C into later intervals (GCAP open: does deferred Class C accrue priority?). ## Domain class policy A domain **MAY** constrain the mix a Member can declare (for example a minimum Class C share for expedited interconnection). Those limits are **commercial-terms** in the domain agreement, not protocol fields. Whether the standard itself should give guidance or limits on differential classes is an RFC #1 open question (Discussion: Commercial terms). Technical membership is spec compliance at a provisioned point of interconnection. Class caps, enforcement of flex capability, and charging for Grid 2-enabled use stay outside DESP/GCAP/G2P. ## Allocator behavior (class-relevant) The Allocator has **no discretion**. Given identical inputs, any conformant GCAP implementation MUST emit identical per-class allocations. | GCAP step | Class effect | |---|---| | 1. Headroom | Surplus network capability for the interval, before any cut | | 2. Buffers | Absorb shortfall or surplus; **before any load curtailment** | | 3. Tiered ramp-down | Reduce Use allocations **C, then B, then A** | | Within class | Proportional to connection size and differential request size | | Stale / partition | Allocator MUST NOT clear; Members fall back | | Ramp safety | Consecutive-interval allocation deltas MUST respect each member's agreed ramp rates | Federation announcements MAY add boundary headroom but MUST NOT relax local constraints. Whether announcements carry **per-class aggregates** or only boundary headroom is open. ## What is not specified yet Treat these as unimplemented, not implied: | Open item | Owner | |---|---| | Assured/Preferred/Best-Efforts vs. Firm/Semi-Firm/Flex names | DESP §5 | | Fixed three classes vs. domain-extensible class count | DESP §5 | | Per-class unmet-frequency envelopes (SLA-like) | DESP §5 | | Per-class ramp-rate and snap-back limits (research cites 15-minute ramp discipline) | DESP §5 | | Enforcement of declared class behavior beyond G2P §3.4 telemetry | DESP §5 | | Exact intra-class proportionality formula | GCAP §7 | | Fairness across intervals for deferred Class C | GCAP §7 | | Standard workload→class mapping per facility type | Use Member; DESP §3 is informative only | | Mid-interval return of unused committed allocation | Use Member open items | | A/B/C structure for Source offers | Source Member (single class in v26.0) | Informative Flex 0–3 and ERCOT CLR/PCLR alignments belong on the mapping page, not in the Allocator. ## Failure and fallback vs. class cuts Class cuts are **normal GCAP output** (a commit-% below 100% on C, then B, then A). Failsafe is different: missing or stale Commitment, lost peers, or an Allocator that withholds clearing. | Event | Use Member | |---|---| | Cleared commit-% < 100% on a class | Self-dispatch that class to the committed share | | No fresh Commitment for the interval | MUST revert to Grid 1 firm load limit or manual curtailment; follow allowed ramps | | Overlay plane down | Same Grid 1 baseline; orchestration failure MUST NOT leave the grid worse than pre-Grid 2 | ## Next Class table, mandatory C-B-A order, domain class-policy limits, and remaining naming/SLA items. Headroom, then buffers, then tiered curtailment; per-class commit outputs; determinism. Informative Flex 0–3 and ERCOT CLR/PCLR mappings; what the Allocator never sees. Per-class consume positions, commit-% listen, self-dispatch MUSTS, firm-limit fallback.