> For the complete documentation index, see [llms.txt](https://hanfak.gitbook.io/workspace/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hanfak.gitbook.io/workspace/networks/duplex.md).

# Duplex

* a mode of communication that allows data to be transmitted in both directions simultaneously.
* enables two endpoints (such as client and server) to send and receive data concurrently, without the need to alternate between sender and receiver roles.
* Two types
  * Half-Duplex:
    * data can be transmitted in both directions, but not at the same time.
    * Each endpoint takes turns sending and receiving data.
    * Not as common as full duplex
    * For example, walkie-talkies operate in half-duplex mode, where one person talks while the other listens, and then they switch roles.
    * Ethernet Hubs:
      * Ethernet hubs operate in a half-duplex mode.
      * In a hub-based Ethernet network, all devices connected to the hub share the same collision domain, which means they cannot transmit and receive data simultaneously.
      * When a device sends data to the hub, the hub broadcasts the data to all connected devices, and collisions can occur if multiple devices transmit at the same time.
      * This collision detection mechanism is a characteristic of half-duplex communication in Ethernet hubs.
  * Full Duplex
    * data can be transmitted in both directions simultaneously.
    * Both endpoints can send and receive data at the same time, allowing for real-time and interactive communication.
    * For example, a telephone conversation is full-duplex, as both parties can speak and listen simultaneously.
    * Examples are
      * Websockets
      * Video conferencing
* It enables efficient and interactive data exchange between two endpoints, facilitating:
  * real-time applications
  * collaborative systems
  * simultaneous data transfer