Define Full Duplex Communication Meaning, example & Benefits

Define Full Duplex Communication

Data can be sent and received simultaneously between two or more connected persons or devices using the full-duplex communication method in networking and telecommunications. It allows two-way communication to occur simultaneously, similar to a telephone call in which both parties may hear and talk at the same time.

You can also read Advantages And Disadvantages Of IPv6, IPv6 Address Types

How Full-Duplex Works

Multiple mechanisms are used to accomplish full-duplex operation:

• Simultaneous Bidirectional Data Flow: Full-duplex communication enables bidirectional (two-way) data flow simultaneously, in contrast to half-duplex communication, which only permits a device to send or receive at the same time.
• Dedicated Wire Pairs: Two wire pairs are usually used in full-duplex Ethernet, one for data transmission and the other for data reception. Because fiber-optic cables have separate transmit (Tx) and receive (Rx) fibers, they are inherently full-duplex.
• Collision-Free Environment: The creation of a collision-free environment is a major benefit of full-duplex operation. This is so that there is no physical chance of collisions because transmitted data is sent on a separate set of wires than received data. Carrier Sense Multiple Access with Collision Detection (CSMA/CD) logic is turned off on devices in full-duplex mode.
• Point-to-Point Connection: A point-to-point connection between the transmitter and receiver of two devices is frequently required for full-duplex functioning.
• Hybrid Coil: To accomplish full-duplex functioning on a two-wire circuit in land-line telephone networks, a hybrid coil is utilized in a telephone hybrid.
• Allowed Connections: Full-duplex applies to several point-to-point connections, such as:
  • Switch to a host
  • Switch to a switch
  • Host to a host
  • Switch to a router
  • Router to a router
  • Router to a host
• No Hubs: When connecting to a hub, full-duplex should not be utilized. For collision detection, a switch port that is connected to a hub and the devices that are connected to that hub must function in half-duplex mode.

Autonegotiation and Duplex Mismatch

Autonegotiation: To negotiate speed and duplex settings with the attached device, modern Ethernet ports employ an auto-detect technique known as autonegotiation (IEEE 802.3u standard). If both devices support it, autonegotiation favors full duplex over half duplex.

Parallel Detection: The other device (doing autonegotiation) will utilize “parallel detection” to gauge speed if one device has autonegotiation turned off. If the speed is 10 Mbps or 100 Mbps, it will select half-duplex; if it is faster (e.g., 1 Gbps), it will select full-duplex.

Duplex Mismatch: When one end of an Ethernet link functions in full-duplex and the other in half-duplex, this is known as a duplex mismatch. This is a prevalent and significant issue that results in poor performance, needless frame discards, and retransmissions because of apparent collisions, yet it does not cause the link to fail. If one end is manually configured for a certain speed and duplex, the other end should likewise be manually configured to match in order to prevent this.

Gigabit Ethernet and Higher: Full duplex is always used by Ethernet connections operating at speeds higher than 1 Gbps, such as Gigabit Ethernet and 10 Gigabit Ethernet. Due to the intrinsic full-duplex nature of the signalling method, half-duplex is very uncommon and undesirable at these rates.

Benefits of Full-Duplex Communication

Compared to other modalities, full-duplex communication has several benefits:

Simultaneous Two-Way Communication: This allows both parties to converse simultaneously in both directions.

No Collisions: Data collisions are impossible because transmitting and receiving are done over different channels. In order to prevent collisions, devices turn down their Carrier Sense Multiple Access with Collision Detection (CSMA/CD) logic.

Higher Throughput and Enhanced Data Speeds: Sending and receiving data at the same time almost doubles the available bandwidth and boosts throughput considerably. A 100 Mbps connection, for instance, can be increased to 200 Mbps (100 Mbps for sending and 100 Mbps for receiving).

Lower Latency and Real-time Interaction: Real-time apps and continuous two-way interactions require no waiting for the channel to become available.

Increased Efficiency: Data transport is faster and more efficient when it occurs simultaneously, which also cuts down on total transmission time.

Reduced Protocol Overhead: Protocol overhead is decreased by doing away with collisions and the requirement for CSMA/CD.

You can also read Frame Switching: Transfer Data Frames Between Devices

Examples of Full-Duplex Systems

Many contemporary communication technologies use full-duplex mode of operation:

Telephones: Traditional examples of devices that allow many people to speak and be heard at the same time include cordless phones, cell phones, and regular telephone service.

Modern Ethernet Networks: Full-duplex mode is nearly usually used by modern Ethernet networks, particularly those that include switches (e.g., Fast Ethernet, Gigabit Ethernet, 10 Gigabit Ethernet).

Fiber Optic Connections: Due to their distinct transmit (Tx) and receive (Rx) fibers, the majority of fiber optic connections are inherently full-duplex.

Real-time Applications: Full-duplex is essential for instantaneous communication in online gaming, video conferencing, and VoIP (Voice over Internet Protocol).

Wireless Technologies: Full-duplex operation is possible with Bluetooth (e.g., in telephone handsets). Full-duplex is also used in mobile technologies like as CDMA2000, UMTS, and LTE.

Serial Peripheral Interface (SPI): The Serial Peripheral Interface (SPI) is a popular full-duplex communication protocol that enables simultaneous data flow between peripherals and microcontrollers.

USB 3.0: While previous USB versions only allowed the half-duplex transmission option, USB 3.0, also referred to as SuperSpeed USB, allows a full-duplex transfer mode.

Configuration

Commands like duplex {full | half | auto} in interface configuration mode on Cisco IOS devices can be used to set up duplex settings. To confirm the selected duplex and speed, use the show interfaces status command.

Full-Duplex in Networking

Switching Technology: By establishing point-to-point virtual circuits between devices, switching technology enables full-duplex operation. This implies that when connecting to a hub, full-duplex should be avoided.

Point-to-Point Connections: switch to host, switch to switch, host to host, switch to router, router to router, and router to host.

Device Capability: The switch port and the Network Interface Card (NIC) need to be able to function in full-duplex mode.

Full-Duplex Emulation (Duplexing Methods)

In point-to-multipoint networks (such as cellular networks), channel access techniques are referred to as duplexing techniques.

Time-Division Duplexing (TDD): This technique simulates full-duplex communication across a half-duplex link by using time-division multiplexing to split outgoing and return signals. It allows for dynamic capacity distribution and is adaptable to asymmetric uplink and downlink data rates. WiMAX, G.fast, DECT wireless telephony, UMTS-TDD, and LTE-TDD are a few examples.

Frequency-Division Duplexing (FDD): With frequency-division duplexing (FDD), distinct carrier frequencies are used by the transmitter and receiver. The frequency offset separates the uplink and downlink sub-bands. By reducing base station interference, FDD simplifies radio planning and is effective for symmetric traffic. ADSL, VDSL, and mobile technologies, including CDMA2000, UMTS, and LTE, are a few examples.

Echo Cancellation

When sound from the far end of a full-duplex audio system, such a telephone, re-enters the near-end microphone and is sent back, it can create echo, which is a delayed reappearance at the original source. Echo cancellation, which is mandated by V.32, V.34, V.56, and V.90 standards, is a signal processing procedure that removes the far-end signal from the microphone signal before to transmission. This is essential for modems to ensure good full-duplex performance.

Disadvantages

Full-duplex systems can have disadvantages despite their many advantages:

Higher Power Consumption: Compared to their half-duplex counterparts, full-duplex devices frequently use more power, which could result in greater energy costs and heat production.

Higher Cost and Complexity: Because full-duplex systems require more complex devices, better cabling, and additional hardware, their implementation can be more costly and difficult.

Comparison of Communication Modes

You can also read MAC Address Tables In Switch For Network Data Forwarding