Node to Node Communication

dbWatch Control Center operates in a distributed architecture, composed of multiple interconnected nodes—including Control Center servers, monitors, routers, and instance hubs. These nodes communicate using a multi-layered protocol designed for security, routing flexibility, and encrypted messaging.

This page explains how node-to-node communication works internally, including how authentication, TLS, and ephemeral encryption are used to securely transmit messages.

This section assumes familiarity with node roles. See Core Concepts & Architecture if you’re new to the terminology.

Layered Protocol Stack

The dbWatch protocol consists of the following layered components:

TCP/IP: Base transport layer for connectivity between nodes
TLS: Encrypted channel with certificate-based mutual authentication
Message Layer: Signed and optionally encrypted messages routed between nodes
Ephemeral Tunnel: Additional end-to-end encryption of message bodies using Diffie-Hellman key exchange

The dbWatch Monitor is considered a node and follows the same communication principles.

1. TCP/IP Layer – Node Connectivity

Nodes connect using standard TCP sockets. Each node may:

Accept incoming connections on one or more ports (e.g., 7100/tcp)
Initiate outbound connections to peer nodes

Configuration options are available in:

Domain Configuration → Topology
`config/node/node.connections` file

Example of a `node.connections` file:

{
  "versionCutoff": "",
  "listenTo": [
    "dbw://localhost:7100"
  ],
  "connectTo": [
    "dbw://cloudrouter1.dbwatch.com:7100"
  ]
}

_See also:_  
"Network and Communication Setup":/ControlCenter/1.0/en/topic/network-and-communications  

---

2. TLS Layer – Secure Transport with Routing Privileges

All TCP communication is wrapped inside a TLS channel, offering:

Encryption in transit (AES/GCM)
Mutual certificate-based authentication
Domain-based routing authorization

Each node presents its domain-issued certificate. During TLS negotiation:

Nodes present proof of routing privileges (based on domain)
A node will only forward traffic between peers that share at least one trusted domain

This ensures zero-trust communication across a multi-node topology.

Learn more about the certificate system here:
Certificate Infrastructure

3. Message Layer – Routed Message Encapsulation

Each dbWatch message includes routing metadata and a cryptographic signature. The message is forwarded across multiple nodes, if necessary, until it reaches its final destination.

Field	Description	Size (bytes)
time to live	Hop count / TTL to avoid loops	1
recipient	IPv6-style recipient address	16
sender	IPv6-style sender address	16
body category	Type of message payload	1
send time	Epoch timestamp	8
certificate ID	ID of signing certificate	8
is body encrypted	Indicates whether payload is encrypted	1
body length	Length of message body	4
message body	Encrypted or plaintext content	variable
signature length	Length of digital signature	4
signature	Signature of all above fields (except TTL)	variable

Messages addressed to the local node are validated and decrypted before processing.
Messages in transit are routed based on recipient address.
Signatures ensure the authenticity and integrity of all messages.

4. Ephemeral Tunnel – End-to-End Message Encryption

Since TLS only encrypts between directly connected nodes, dbWatch uses a second encryption layer for message confidentiality:

Each pair of nodes performs an Elliptic-Curve Diffie-Hellman (ECDH) handshake
The derived ephemeral session key is used to encrypt the message body before it enters the network
This ensures end-to-end secrecy, even if an intermediate router node is compromised
It also provides forward secrecy: compromising a server’s certificate later will not reveal historical traffic

This layered encryption approach protects against:

Packet sniffing
Man-in-the-middle attacks
Message tampering or spoofing

Learn more:
Encryption and Ephemeral Keys

Key Advantages

Secure multi-hop routing of messages between nodes
Authentication and domain-aware routing via certificates
TLS protection combined with forward-secret message encryption
Configurable listening and connection topologies
Supports air-gapped, segmented, or cloud-native deployments