> ## Documentation Index
> Fetch the complete documentation index at: https://voltaire.tevm.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# ProtocolVersion

> Ethereum wire protocol version identifier for peer-to-peer communication

# ProtocolVersion

Ethereum wire protocol version identifier for P2P network communication.

## Overview

ProtocolVersion represents the version of the Ethereum wire protocol used for peer-to-peer communication between nodes. Protocol versions define capabilities and message formats for node synchronization.

## Type Definition

```typescript theme={null}
type ProtocolVersionType = string & {
  readonly __tag: "ProtocolVersion";
};
```

## Protocol Versions

| Constant | Value      | Description              |
| -------- | ---------- | ------------------------ |
| `ETH_66` | `"eth/66"` | ETH66 protocol           |
| `ETH_67` | `"eth/67"` | ETH67 protocol           |
| `ETH_68` | `"eth/68"` | ETH68 protocol (current) |
| `SNAP_1` | `"snap/1"` | Snapshot sync protocol   |

## Usage

### Create Protocol Version

```typescript theme={null}
import * as ProtocolVersion from './primitives/ProtocolVersion/index.js';

const version = ProtocolVersion.from("eth/68");
```

### Use Constants

```typescript theme={null}
import { ETH_68, SNAP_1 } from './primitives/ProtocolVersion/index.js';

console.log(ETH_68);  // "eth/68"
console.log(SNAP_1);  // "snap/1"
```

### Compare Versions

```typescript theme={null}
const isEqual = ProtocolVersion.equals("eth/67", "eth/68");
// false

const comparison = ProtocolVersion.compare("eth/66", "eth/68");
// -2 (eth/66 is 2 versions behind eth/68)
```

### Convert to String

```typescript theme={null}
const str = ProtocolVersion.toString("eth/68");
// "eth/68"
```

## API Reference

### Constructors

| Function        | Description                |
| --------------- | -------------------------- |
| `from(version)` | Create from version string |

### Methods

| Function          | Description                         |
| ----------------- | ----------------------------------- |
| `toString(v)`     | Convert to string representation    |
| `equals(v1, v2)`  | Check if versions are equal         |
| `compare(v1, v2)` | Compare version ordering (-1, 0, 1) |

### Constants

| Constant | Description                      |
| -------- | -------------------------------- |
| `ETH_66` | ETH protocol version 66          |
| `ETH_67` | ETH protocol version 67          |
| `ETH_68` | ETH protocol version 68          |
| `SNAP_1` | Snapshot sync protocol version 1 |

## Protocol History

### ETH/66 (Berlin)

* Typed transactions support
* Receipt status encoding

### ETH/67 (London)

* Removed `GetNodeData`/`NodeData` messages
* Required for nodes after The Merge

### ETH/68 (Current)

* Transaction announcements include type and size
* Improved transaction pool management

### SNAP/1

* Snapshot synchronization protocol
* Fast state sync via state snapshots

## Node Communication

When connecting to peers, nodes exchange supported protocol versions:

```typescript theme={null}
// Example peer capabilities
const peerCaps = [
  ProtocolVersion.from("eth/68"),
  ProtocolVersion.from("eth/67"),
  ProtocolVersion.from("snap/1"),
];

// Find highest compatible ETH version
const ethVersions = peerCaps.filter(v => v.startsWith("eth/"));
const highest = ethVersions.sort(ProtocolVersion.compare).pop();
```

## See Also

* [Chain](/primitives/chain) - Chain configuration
* [Hardfork](/primitives/hardfork) - Ethereum hardforks