# Electra -- Networking

This document contains the consensus-layer networking specification for Electra.

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

## Table of contents

<!-- TOC -->
<!-- START doctoc generated TOC please keep comment here to allow auto update -->
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->

- [Modifications in Electra](#modifications-in-electra)
  - [The gossip domain: gossipsub](#the-gossip-domain-gossipsub)
    - [Topics and messages](#topics-and-messages)
    - [Global topics](#global-topics)
      - [`beacon_aggregate_and_proof`](#beacon_aggregate_and_proof)
    - [Attestation subnets](#attestation-subnets)
      - [`beacon_attestation_{subnet_id}`](#beacon_attestation_subnet_id)

<!-- END doctoc generated TOC please keep comment here to allow auto update -->
<!-- /TOC -->

## Modifications in Electra

### The gossip domain: gossipsub

Some gossip meshes are upgraded in the fork of Electra to support upgraded types.

#### Topics and messages

Topics follow the same specification as in prior upgrades.

The `beacon_block` topic is modified to also support Electra blocks.

The `beacon_aggregate_and_proof` and `beacon_attestation_{subnet_id}` topics are modified to support the gossip of the new attestation type.

The `attester_slashing` topic is modified to support the gossip of the new `AttesterSlashing` type.

The specification around the creation, validation, and dissemination of messages has not changed from the Capella document unless explicitly noted here.

The derivation of the `message-id` remains stable.

#### Global topics

##### `beacon_aggregate_and_proof`

The following convenience variables are re-defined
- `index = get_committee_indices(aggregate.committee_bits)[0]`

The following validations are added:
* [REJECT] `len(committee_indices) == 1`, where `committee_indices = get_committee_indices(aggregate)`.
* [REJECT] `aggregate.data.index == 0`

#### Attestation subnets

##### `beacon_attestation_{subnet_id}`

The following convenience variables are re-defined
- `index = get_committee_indices(attestation.committee_bits)[0]`

The following validations are added:
* [REJECT] `len(committee_indices) == 1`, where `committee_indices = get_committee_indices(attestation)`.
* [REJECT] `attestation.data.index == 0`