---
id: basics-zil-nodes
title: Types of Nodes
keywords:
  - type of nodes
  - shard nodes
  - ds nodes
  - lookup nodes
  - seed nodes
  - staked seed nodes
description: Zilliqa Types Of Nodes
---

---

The Zilliqa Mainnet is composed of several types of nodes that perform different
functions or provide specialized services.

!["Network Layout Image 1"](../../assets/img/contributors/core/network-layout/image01.png)

## Shard Nodes

Shard nodes are the mining nodes in the Zilliqa Network. They are named as such
because they are assigned to one of several clusters (i.e., shards) within the
network. Nodes that belong to the same shard process the same set of
transactions assigned to their shard. After processing, the nodes must achieve
consensus over the transaction set in order to generate the shard's microblock.
For their work, shard nodes are rewarded $ZIL at the end of every DS epoch.

Shard membership is determined by the DS committee after shard nodes
successfully submit solutions to a Proof-of-Work (PoW) problem, which occurs
once every DS epoch.

## DS Nodes

DS (Directory Service) nodes are also mining nodes, with the additional
responsibilities of (1) aggregating shard microblocks to form the Transaction
Block and (2) creating the DS Block at the start of every DS epoch. As with the
shard nodes, DS nodes are rewarded $ZIL at the end of every DS epoch.

The collection of DS nodes in the network is referred to as the DS committee.
Unlike the shards, which are completely revised every DS epoch, the DS committee
stays relatively stable across several DS epochs, as only a small fraction of
the committee is replaced every DS epoch. DS committee membership is determined
by Proof-of-Work of a higher difficulty. The length of a DS node's tenure within
the committee is also affected by its performance within the duration of the DS
epoch.

## Lookup Nodes

Lookup nodes are full nodes, i.e., they store all of the blockchain data
generated by the DS and shard nodes (including transactions, microblocks,
Transaction Blocks, and DS Blocks). They provide the data to nodes that are
syncing with or attempting to join the network. Lookups also dispatch
transactions to the shards and DS Committee.

## Seed Nodes

Seed nodes are full nodes (like lookup nodes) that do not directly dispatch
transactions to the shards and DS committee. They are used mainly for serving
JSON-RPC requests, including creating new transactions. Transactions are
regularly bundled by seed nodes and forwarded to lookups for eventual dispatch
to the shards and DS committee.

## Staked Seed Nodes

Staked seed nodes (SSNs) are a variant of seed nodes. SSNs are run by staking
partners and are expected to serve JSON-RPC requests from the community. In
return for the service, these nodes are regularly given staking rewards in the
form of $ZILs. Staking rewards are determined based on the performance of the
SSN. For more information on staked seed nodes, please refer to our staking
feature documentation in
[Zilliqa Improvement Proposal #3](https://github.com/Zilliqa/ZIP/blob/master/zips/zip-3.md).