EIP-8198 -- Networking¶

Note: This document is a work-in-progress for researchers and implementers.

Introduction¶

This document contains the consensus-layer networking specifications for EIP-8198.

The specification of these changes continues in the same format as the network specifications of previous upgrades, and assumes them as pre-requisite.

Note: This specification is built upon Heze.

Configs¶

Note: MIN_BLOB_DATA_RETENTION_MS replaces MIN_EPOCHS_FOR_DATA_COLUMN_SIDECARS_REQUESTS with the same duration, defined in wall-clock time rather than epochs.

Modifications in EIP-8198¶

Helpers¶

Modified compute_fork_version¶

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def compute_fork_version(epoch: Epoch) -> Version:
    """
    Return the fork version at the given ``epoch``.
    """
    if epoch >= EIP8198_FORK_EPOCH:
        return EIP8198_FORK_VERSION
    if epoch >= HEZE_FORK_EPOCH:
        return HEZE_FORK_VERSION
    if epoch >= GLOAS_FORK_EPOCH:
        return GLOAS_FORK_VERSION
    if epoch >= FULU_FORK_EPOCH:
        return FULU_FORK_VERSION
    if epoch >= ELECTRA_FORK_EPOCH:
        return ELECTRA_FORK_VERSION
    if epoch >= DENEB_FORK_EPOCH:
        return DENEB_FORK_VERSION
    if epoch >= CAPELLA_FORK_EPOCH:
        return CAPELLA_FORK_VERSION
    if epoch >= BELLATRIX_FORK_EPOCH:
        return BELLATRIX_FORK_VERSION
    if epoch >= ALTAIR_FORK_EPOCH:
        return ALTAIR_FORK_VERSION
    return GENESIS_FORK_VERSION

New compute_blob_data_retention_start_epoch¶

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def compute_blob_data_retention_start_epoch(epoch: Epoch) -> Epoch:
    """
    Return the start epoch of the blob data retention window,
    preserving its wall-clock length across slot duration changes.
    """
    window_ms = MIN_BLOB_DATA_RETENTION_MS
    current_start_slot = compute_start_slot_at_epoch(epoch)
    current_start_ms = compute_time_at_slot_ms(Uint64(0), current_start_slot)
    if current_start_ms < window_ms:
        return GENESIS_EPOCH
    window_start_ms = Uint64(current_start_ms - window_ms)
    return compute_epoch_at_slot(compute_slot_at_time_ms(Uint64(0), window_start_ms))

The gossip domain: gossipsub¶

Each duration schedule entry after genesis MUST coincide with a network upgrade at or after EIP8198_FORK_EPOCH. Clients SHOULD subscribe to the new fork-digest topics ahead of the upgrade epoch and unsubscribe from the old topics after it.

Durations defined in slots or epochs MUST use the piecewise timeline (compute_time_at_slot_ms / compute_slot_at_time_ms). For example, the gossipsub seen_ttl is the difference between the start times of current_slot + 2 * SLOTS_PER_EPOCH and current_slot, converted to seconds with milliseconds_to_seconds. Duty schedulers and the light-client local-clock current_slot MUST also use this timeline. Durations configured in milliseconds, including data column sidecar retention, remain fixed in wall-clock time.

The Req/Resp domain¶

Status v2¶

Protocol ID: /eth2/beacon_chain/req/status/2/

[Modified in EIP8198] The data column sidecar retention period used to determine earliest_available_slot begins at epoch max(compute_blob_data_retention_start_epoch(current_epoch), FULU_FORK_EPOCH).

DataColumnSidecarsByRange v1¶

Protocol ID: /eth2/beacon_chain/req/data_column_sidecars_by_range/1/

[Modified in EIP8198] The data_column_serve_range is modified to [max(compute_blob_data_retention_start_epoch(current_epoch), FULU_FORK_EPOCH), current_epoch].

DataColumnSidecarsByRoot v1¶

Protocol ID: /eth2/beacon_chain/req/data_column_sidecars_by_root/1/

[Modified in EIP8198] The data_column_serve_range is modified to [max(compute_blob_data_retention_start_epoch(current_epoch), FULU_FORK_EPOCH), current_epoch].