Data is broken down into small units called packets, each containing payload data along with source and destination address headers. Data forwarding is carried out by specialized network hardware:

• Switches: Connect devices within a local network (LAN) and forward frames directly to target devices using MAC addresses.
• Routers: Interconnect different networks and determine the optimal path for packets using IP addresses, routing data hop-by-hop across networks (e.g., connecting a home LAN to the Internet).
• Access Points: Enable wireless devices to connect to a wired network via Wi-Fi.
• Firewalls: Inspect inbound and outbound traffic against defined security policies to block unauthorized access.

For TCP-based communication, data transfer begins only after completing a three-way handshake:

1. The client sends a SYN (synchronize) message.
2. The server responds with a SYN-ACK message to acknowledge.
3. The client replies with an ACK message, establishing the connection.

Once the connection is established, data packets travel independently across routers and are reassembled in proper order at the destination.