Owner: @Daniel Sanchez Quiros

Reviewers: 🟢@Álvaro Castro-Castilla 🟢@Daniel Kashepava 🟢@Gusto Bacvinka 🟢@Marcin Pawlowski

Introduction

The NomosDA replication sub-protocol describes how nodes spread dispersed DA blobs within the NomosDA subnetworks. Only DA nodes listed in the Service Declaration Protocol (SDP) are entitled to participate in these subnetworks. This document establishes the protocol structure abstracted from the network construction that can be found in the NomosDA network specification.

NomosDA replication aims to provide a simple method for nodes within a NomosDA subnetwork to redistribute data previously dispersed to one of the subnetwork participants. The protocol has the following requirements:

• Make efficient use of bandwidth.
• Re-use connections as much as possible.
• Lightweight on data verification. Validation should be efficient.
• Flexible. Nodes may come and go. Therefore, other nodes must adapt to changes so data is not lost during the process.

Overview

DA nodes may receive encoded data either from an encoder (through the dispersal protocol) or from other participating nodes through the sub-protocol described here. Nodes validate the incoming data and then forward it to all connected nodes within the same subnetwork where the data is intended to be distributed.

Protocol

Prerequisites

The replication protocol begins when a node receives an encoded share of data. This data can come from two sources:

• An encoder performing dispersal;
• A DA node that has already received the data through either dispersal or replication.

Before proceeding, the received data must be verified.

Replication

The replication sub-protocol begins when a node receives and validates an encoded data share from an encoder. The process works as follows:

1. The node sends the validated Mantle Transaction of the encoded data share.