asymmetric communications

What is Asymmetric Communication?

Asymmetric communication refers to any system where the data transfer rate or volume differs between the two directions over time. Often called asymmetrical or nonsymmetrical communication, it contrasts with symmetric communication, where data speeds are consistent in both directions over a given period.

Unlike symmetric communication, which offers equal upload and download speeds, asymmetric communication typically results in varied speeds. This is commonly seen in traditional internet connections, where download speeds are much higher than upload speeds, or in wireless networks, where data is transmitted through different nodes with varying latency, packet error rates, and bandwidth.

Examples of Asymmetric Communications

A common example of asymmetric communication is Asymmetric Digital Subscriber Line (ADSL). ADSL technology uses existing phone lines to transmit digital data at high bandwidth. It is considered asymmetric because most of the bandwidth is used for downstream data (from the server to the user), while only a small portion is used for upstream data (from the user to the server).

Other examples of asymmetric communication systems include:

Fiber to the Curb/Cabinet (FTTC)

• Combines fiber and copper cables

• Fiber runs from the telephone exchange to roadside cabinets, then connects to standard phone lines at business premises via copper cables for broadband delivery

• Provides faster upload and download speeds compared to traditional ADSL

• Ideal for small and medium-sized businesses

Fiber to the Premises/Home (FTTP/FTTH)

• Uses only fiber optics, eliminating copper cables

• Extends fiber directly from the local exchange to the end-user premises, providing internet access without the need for a telephone line

• Delivers high-speed data through dedicated fiber connections to each end-user

• More costly than FTTC due to the higher fiber infrastructure requirements

Advantages and Disadvantages of Asymmetrical Communications

Advantages:

• Efficient use of infrastructure: Asymmetrical data flows can make better use of available infrastructure compared to symmetrical ones. This is particularly common in large enterprise or service provider networks with multiple entry and exit points.

• Cost-effective and easier to install: Asymmetric systems typically offer fast download speeds and are easier and more affordable to set up, making them ideal for smaller organizations that don’t require high-speed upstream data.

• Improved performance for specific use cases: Asymmetric connections work well for typical consumer internet usage, where download speeds are more crucial than upload speeds, such as for streaming, browsing, and content consumption.

Disadvantages:

• Performance dependent on local usage: The performance of asymmetric communications can be closely tied to usage patterns within the organization's local network, which may cause bottlenecks or inefficiencies.

• Limitations for certain applications: Asymmetric communications may not be suitable for all use cases, especially where bidirectional data transfer is crucial. For example, in two-way, full-motion video conferencing, unequal upload and download speeds can affect communication quality. Similarly, applications like File Transfer Protocol (FTP) that require high upstream data volumes can be hindered by asymmetric speeds. In such cases, alternative solutions like optical fiber or broadband cable may be more appropriate.