* feat(isolation): add RFC 0012 backend contract Signed-off-by: Drew Newberry <385+drew@users.noreply.github.com> * refactor(isolation): name the interface crate explicitly Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(isolation): expose trusted host gateway Signed-off-by: Drew Newberry <anewberry@nvidia.com> * docs(agents): inventory the MXC driver Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(isolation): add mediated DNS transport Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): tighten interface error and digest contracts Signed-off-by: Drew Newberry <anewberry@nvidia.com> * docs(isolation): remove unrelated driver inventory Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(isolation): define capability-free launch contract Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): seal confirmed boundary state Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): validate confirmation for external backend implementations Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): clarify mediated DNS identity Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(isolation): generalize loopback connector Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(isolation): unify typed network mediation Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(isolation): bind launches to sandbox sessions Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(mxc): initialize extended sandbox status Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(isolation): add boundary protocol and Linux primitives Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): harden signals and separate process status from transport Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): validate remote confirmation through public contract Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): validate wire state and propagate snapshot failures Signed-off-by: Drew Newberry <anewberry@nvidia.com> * test(isolation): import owned agent specification explicitly Signed-off-by: Drew Newberry <anewberry@nvidia.com> * docs(isolation): describe mediated DNS channel Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): bound mediation attach without nested retries Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(isolation): generalize loopback protocol Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(isolation): add transport-neutral session authentication Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(isolation): separate sandbox backend protocol Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): harden runtime boundary controls Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(isolation): add terminal boundary operation Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(isolation): split supervisor and sandbox runtimes Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(sandbox): harden boundary isolation and lifecycle ownership Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(sandbox): reject private root redirects and adopt typed errors Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(sandbox): preserve accept thread ownership on musl Signed-off-by: Drew Newberry <anewberry@nvidia.com> * test(sandbox): isolate credential probes from filtered threads Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(sandbox): return retained exec exit status to independent waiters Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(sandbox): bound network mediation and preserve socket authorization Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(sandbox): bound control admission and retire stale mediation Signed-off-by: Drew Newberry <anewberry@nvidia.com> * ci(e2e): select migrated drivers per stack layer Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(sandbox): implement loopback connector Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(isolation): authenticate the Sandbox Protocol Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(supervisor): rotate launch-scoped authentication Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(sandbox): consume dedicated backend crate Signed-off-by: Drew Newberry <anewberry@nvidia.com> * test(sandbox): align topology session fixture Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(sandbox): align projected bootstrap bundle Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(auth): validate refreshed credentials before rotation Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(sandbox): fail closed across supervisor disconnects Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): repair rebased sandbox CI Signed-off-by: Drew Newberry <anewberry@nvidia.com> * build(runtime): publish separate sandbox and supervisor images Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(config): configure the sandbox runtime image Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(ci): validate sandbox binary linkage Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(isolation): use backend and runtime terminology Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(sandbox): use a scratch runtime image Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(ci): refresh schema and dependency policy Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(sandbox): bind reconnects to supervisor process Signed-off-by: Drew Newberry <anewberry@nvidia.com> * docs: align runtime split operational guidance Signed-off-by: Drew Newberry <anewberry@nvidia.com> * chore(security): document Kubernetes runtime RBAC Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): enforce runtime lifecycle invariants Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(compute): identify sandbox start generations Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(server): restore sandbox launch sessions Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): support authenticated runtime replacement Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(auth): bind sandbox session successors Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(auth): retry pending sandbox successors Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(vm): run the supervisor outside the guest workload Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(vm): use sandbox backend protocol Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): repair rebase integration Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): use unified build toolchain Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(vm): use sandbox runtime terminology Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(vm): own guest network bootstrap Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): expose guest init version Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): select native supervisor artifacts Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): guard guest init Linux symbols Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): scope Linux test imports Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): avoid guest interface casts Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): reconcile admitted sandbox identity Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): share resolved sandbox identity Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): surface host supervisor failures Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): include guest logs on supervisor exit Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): rotate and clean runtime generations Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): make sandbox starts generation-aware Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): rotate restored sandbox sessions Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(vm): keep shared paths in the base layer Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): bind sandbox session lineage Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(docker): isolate workloads behind the host supervisor Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(docker): rotate launch-scoped authentication Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(docker): use sandbox backend protocol Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(docker): use host networking for supervisor Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): preserve host gateway alias resolution Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(docker): use separate sandbox and supervisor images Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): restore startup validation after rebase Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(docker): name the sandbox runtime directly Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): narrow supervisor CA runtime storage Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): close companion isolation gaps Signed-off-by: Drew Newberry <anewberry@nvidia.com> * test(docker): align mediated network expectations Signed-off-by: Drew Newberry <anewberry@nvidia.com> * test(docker): exercise mediated network paths Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): attach supervisor to managed network Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): defer supervisor recovery until gateway is ready Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): make sandbox starts generation-aware Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): rotate restored sandbox sessions Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): preserve workloads during session rotation Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(docker): remove unrelated configuration RFC changes Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): bind sandbox session lineage Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(kubernetes): add proxy-pod isolation topology Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(kubernetes): use sandbox backend protocol Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): use stable sandbox service authority Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(kubernetes): split sandbox and supervisor images Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): adapt proxy pods to current runtime APIs Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(kubernetes): describe the single runtime placement Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(kubernetes): simplify sandbox orchestration Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): validate deployment prerequisites Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): update Trivy Helm profile inventory Signed-off-by: Drew Newberry <anewberry@nvidia.com> * test(kubernetes): update Trivy scan inventory count Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): reuse preloaded runtime images in e2e Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): type and clean runtime resources Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): make sandbox restarts recoverable Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): rotate restored sandbox sessions Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): preserve supervisor egress Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): bind sandbox session lineage Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(podman): adopt isolated sandbox and supervisor containers Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): stage bootstrap archives at named volume destinations Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(podman): rotate launch-scoped authentication Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(podman): use sandbox backend protocol Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(podman): use host networking for supervisor Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(podman): split sandbox and supervisor images Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): repair rebase integration Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(podman): name the sandbox runtime directly Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): provision supervisor CA runtime storage Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): address isolation review findings Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): inspect Debian supervisor provenance Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): use libpod-compatible tmpfs options Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): bind verified sandbox runtime binary Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): provide external driver data directory Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): start sandbox before joining user namespace Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): separate supervisor user namespace Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): make sandbox starts generation-aware Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): rotate restored sandbox sessions Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): bind sandbox session lineage Signed-off-by: Drew Newberry <anewberry@nvidia.com> * perf(isolation): add TCP and DNS benchmark harnesses Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(perf): align benchmark timing and supported protocols Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(perf): report TCP benchmark metrics accurately Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(perf): cancel failed worker startup Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(docker): build matching local supervisor image Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(podman): make local sandbox smoke test runnable Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): wire local sandbox runtime image Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(kubernetes): narrow sandbox service RBAC Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(ci): validate split runtime artifacts Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): harden runtime session handling Signed-off-by: Drew Newberry <anewberry@nvidia.com> * feat(supervisor): add standalone network proxy role Signed-off-by: Drew Newberry <anewberry@nvidia.com> * docs(rfc): remove implementation companion notes Signed-off-by: Drew Newberry <anewberry@nvidia.com> * refactor(vm): standardize runtime release name Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(vm): pin renamed runtime artifacts Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(auth): persist sandbox runtime identity Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(runtime): restore branch validation Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(isolation): reconcile main after rebase Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(network): close unframed HTTP 1.0 responses Signed-off-by: Drew Newberry <anewberry@nvidia.com> * chore(isolation): preserve upstream OCSF updates Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(security): close credential and TLS replay paths Signed-off-by: Drew Newberry <anewberry@nvidia.com> * fix(auth): make sandbox refresh retries idempotent Signed-off-by: Drew Newberry <anewberry@nvidia.com> --------- Signed-off-by: Drew Newberry <385+drew@users.noreply.github.com> Signed-off-by: Drew Newberry <anewberry@nvidia.com>
OpenShell RFCs
Substantial changes to OpenShell should be proposed in writing before implementation begins. New features always start as a GitHub issue using the feature request template, not as an RFC pull request. RFCs drive nuanced discussions that need structured iteration, broad stakeholder input, and a durable record of the reasoning beyond what issue comments can fully capture.
An RFC provides a consistent way to collect broad feedback, build consensus, and document the decision for future contributors. An RFC is created only when maintainers decide the originating issue needs that level of design review.
Start with a GitHub issue
Before writing an RFC, you must open a GitHub issue to scope the problem, gauge interest, and get early feedback. For new features, use the feature request template. This helps:
- Validate that the problem is worth solving
- Surface potential concerns early
- Build consensus before investing in a detailed proposal
- Identify the right reviewers and stakeholders
If the ticket shows sufficient interest and maintainers decide the idea needs broad design review, they will ask for an RFC from that issue. Maintainers assign the RFC number and add the needs-rfc label in the issue before the RFC is created, preventing number clashes across branches and making pending RFC work searchable.
RFCs vs other artifacts
OpenShell has several places where design information lives. Use this guide to pick the right one:
| Artifact | Purpose | When to use |
|---|---|---|
| GitHub issue | Track and scope a bug, feature request, or rough idea | Always start here; new features use the feature request template |
Spike issue (create-spike) |
Investigate implementation feasibility for a scoped change | You need to explore the codebase and produce a buildable issue for a specific component or feature |
| RFC | Propose a cross-cutting decision that needs broad consensus | Maintainers requested an RFC from an existing issue and assigned an RFC number |
Architecture doc (architecture/) |
Document how things work today | Living reference material — updated as the system evolves |
The key distinction: spikes investigate whether and how something can be done; RFCs propose that we should do it and seek agreement on the approach. A spike may precede an RFC (to gather data) or follow one (to flesh out implementation details). When an RFC reaches implemented, its relevant content should be folded into the appropriate architecture/ docs so the living reference stays current.
When to use an RFC
Use an RFC when the discussion itself needs structure: multiple rounds of feedback, competing tradeoffs, broad stakeholder input, or a durable design record. If the important context would get lost across issue comments, an RFC is the right tool. The following are examples of when maintainers may ask for one after an issue is opened:
- An architectural or design decision for the platform
- Change to an API or command-line tool
- Change to an internal API or tool
- Add or change a company or team process
- A design for testing
RFCs don't only apply to technical ideas but overall project ideas and processes as well. If you have an idea to improve the way something is being done, you have the power to make your voice heard.
When NOT to use an RFC
Not everything needs an RFC. Skip the RFC process for:
- Bug fixes
- Small feature additions scoped to a single component (use a spike instead)
- Feature requests that can be resolved through the issue, spike, and pull request workflow
- Documentation changes
- Dependency updates
- Refactoring that doesn't change public interfaces
If a change doesn't require cross-team consensus, a GitHub issue or spike issue is the right vehicle.
RFC metadata and state
At the start of every RFC document, we include a brief amount of metadata in YAML front matter:
---
authors:
- "@username"
state: draft
links:
- https://github.com/NVIDIA/OpenShell/issues/456
- https://github.com/NVIDIA/OpenShell/pull/123
---
We track the following metadata:
- authors: The authors (and therefore owners) of an RFC. Listed as GitHub usernames.
- state: Must be one of the states discussed below.
- links: Related PRs or issues. The first link should be the originating issue where maintainers requested the RFC and assigned its number. Add entries as the RFC progresses.
- superseded_by: (optional) For RFCs in the
supersededstate, the RFC number that replaces this one (e.g.,0005).
An RFC can be in one of the following states:
| State | Description |
|---|---|
draft |
The RFC is being written and is not yet ready for formal review. |
review |
Under active discussion in a pull request. |
accepted |
The proposal has been accepted and is ready for implementation. |
rejected |
The proposal was reviewed and declined. |
implemented |
The idea has been entirely implemented. Changes would be infrequent. |
superseded |
Replaced by a newer RFC. The superseded_by field should reference the replacement. |
RFC lifecycle
1. Open a GitHub issue
Start with a GitHub issue. New features must use the feature request template and include enough design context for maintainers and contributors to evaluate the idea. Do not open an RFC PR before an issue exists.
2. Get maintainer confirmation
Maintainers decide from the issue whether an RFC is necessary. If it is, they assign the RFC number in the issue before anyone creates the RFC branch or folder, and add the needs-rfc label to the originating issue so pending RFC work is searchable. Authors should use the assigned number instead of choosing one locally.
3. Create your RFC
Each RFC lives in its own folder:
rfc/NNNN-my-feature/
README.md
(optional: diagrams, images, supporting files)
Where NNNN is the maintainer-assigned RFC number (zero-padded to 4 digits) and my-feature is a short descriptive name. The main proposal goes in README.md so GitHub renders it when browsing the folder.
To start a new RFC, copy the template folder:
cp -r rfc/0000-template rfc/NNNN-my-feature
Fill in the metadata, include the originating issue in links, and start writing. The state should be draft while you're iterating.
4. Open a pull request
When you're ready for feedback, update the state to review and open a pull request. Add the PR link to links in the metadata. Maintainers should add the rfc label to the PR and add it to the RFC board.
The PR is where discussion happens. Anyone subscribed to the repo will get a notification and can read your RFC and provide feedback.
5. Iterate and build consensus
The comments you choose to accept are up to you as the owner of the RFC, but you should remain empathetic in how you engage. For those giving feedback, be sure that all feedback is constructive.
RFCs rarely go through this process unchanged. Make edits as new commits to the PR and leave comments explaining your changes.
6. Merge the pull request
After there has been time for folks to comment, the RFC author requests merge and a maintainer approves and merges. The state should be updated from review to accepted. If the proposal is declined, the state should be set to rejected. The timing is left to the author's discretion. As a guideline, a few business days seems reasonable, but circumstances may dictate a different timeline.
When an RFC is accepted, maintainers should update any RFC board fields that track review state.
In general, RFCs shouldn't be merged if no one else has read or commented on it. If no one is reading your RFC, it's time to explicitly ask someone to give it a read!
7. Implementation
Once an RFC has been entirely implemented, its state should be moved to implemented. This represents ideas that have been fully developed. While discussion on implemented RFCs is permitted, changes would be expected to be infrequent.
Diagrams
When an RFC needs diagrams to illustrate architecture, data flow, or component interactions, use Mermaid diagrams embedded directly in the Markdown. Mermaid renders natively on GitHub and keeps diagrams version-controlled alongside the text.
```mermaid
graph LR
A[Client] --> B[Gateway]
B --> C[Sandbox]
```
Prefer Mermaid over external image files whenever possible. If a diagram is too complex for Mermaid (e.g., detailed UI mockups), commit the image to the RFC's folder alongside its README.md and reference it with a relative path.
Making changes to an RFC
After your RFC has been merged, there is always opportunity to make changes. Open a pull request with the change you would like to make. If you are not the original author, be sure to @ the original authors to make sure they see and approve of the changes.
RFC postponement
Some RFCs are marked rejected when the proposal is declined or when we want neither to think about evaluating the proposal nor about implementing it until some time in the future. Rejected RFCs may be revisited when the time is right.