Different Types of Network Sockets and Their Usage

In computer networking, a socket acts as a link between two devices, facilitating two-way communication on a network. It receives and sends data to the connected devices, enabling seamless data transfer. A socket address, which is a combination of an IP address and a port, identifies whether the data should be sent to a specific application or not. The transport layer, particularly the socket, plays a vital role in managing and establishing communication between devices. In this article, we will learn about different types of sockets and their uses.

Sockets serve as communication devices that enable interactions between clients and servers. They receive information from clients, send information back, and disconnect once the data transfer is complete. There are different types of sockets available, each serving a specific purpose in network communication. Let’s explore these types in detail:

Datagram Sockets

Datagram sockets allow processes to use the User Datagram Protocol (UDP) for communication. UDP is a two-way flow of communication that enables the exchange of messages between devices. Unlike other socket types, datagram sockets do not guarantee the order of received messages or prevent the reception of duplicate messages. These sockets maintain message boundaries, ensuring that the received data retains its original structure. Datagram sockets are identified by the socket type SOCK_DGRAM

Datagram sockets, typically implemented using the User Datagram Protocol (UDP), send and receive individual packets called datagrams. Each datagram is treated independently and may arrive out of order, be duplicated, or even get lost.

Stream Sockets

Stream sockets, on the other hand, enable processes to use the Transfer Control Protocol (TCP) for communication. TCP provides a sequenced, reliable, and bidirectional flow of data. Devices can establish a connection and read and write data to stream sockets as a continuous stream of bytes. Stream sockets are particularly useful for applications that require reliable and ordered data transmission. The socket type for stream sockets is SOCK_STREAM.

Stream sockets, typically implemented using the Transmission Control Protocol (TCP), provide a reliable, ordered, and bidirectional byte stream. Data is sent in a continuous stream, similar to how water flows through a pipe, ensuring it arrives in the correct order without duplicates or gaps.

Raw Sockets

Raw sockets offer low-level access to the underlying network protocols and packet headers. This allows for fine-grained control over network traffic, enabling applications to directly manipulate and analyze network packets.

Most applications do not commonly use these sockets but they are valuable for developing new communication protocols or accessing additional features of existing protocols. Raw sockets have characteristics similar to datagram sockets, with their behavior dependent on the underlying interfaces. Access to raw sockets is restricted to superusers. The socket type for raw sockets is SOCK_RAW.

Unix Domain Socket

Unix domain sockets enable inter-process communication (IPC) within a single host. They use the host’s file system for addressing, offering fast and efficient communication between local processes.

Connection needs to be established between the sender and receiver within the same system. It supports communication between processes within the same application, sharing data between services running on the same server, and local IPC tasks.

What are different network sockets?

Here’s a table comparing different types of network sockets:

Socket Type	Description	Transport Protocol	Connection-Oriented	Reliable	Typical Use Cases
Stream Socket (TCP)	Provides a reliable, ordered, bidirectional byte stream	TCP	Yes	Yes	Web browsing, file transfers, email, remote access
Datagram Socket (UDP)	Sends and receives individual packets (datagrams) without guaranteed delivery	UDP	No	No	Streaming media, online gaming, DNS, real-time applications
Raw Socket	Low-level access to network protocols and packet headers	Various (IP, ICMP, etc.)	Varies	Varies	Network monitoring, packet analysis, custom protocol development
Unix Domain Socket	Inter-process communication within a single host	–	Unix file system	Varies	Communication between local processes, IPC

Related read: history of data communication protocols