Ethernet Cable vs. Optical Fiber Cable

- Ethernet Cable

Ethernet is probably most widely known because of the short Ethernet patch cables with their RJ45 connectors which are used to connect most desktop computers to data network routers. These make Ethernet connections very easy to make, thereby increasing the ease of use and popularity of Ethernet technology.  

Ethernet is a popular method of networking computers in a local area networks (LANs) using copper cabling. Due to our ever increasing demand for speed, gigabit Ethernet is emerging as the go-to Ethernet option. Its cables are comprised of multiple strands of copper wire that are twisted together, with four twisted wire pairs per cable. Two of the pairs are used to send data, and the other two are used to receive data. 

Data is transmitted via electrical signals sent through copper cabling. Cat 5e and Cat 6 cables are designed for high speed gigabit Ethernet. While optical fiber cable is common for links between network switches, use of fiber to the desktop is rare.

Early Ethernet (10BASE-5 and 10BASE-2) used coaxial cable. Shielded twisted pair was used in IBM's Token Ring LAN implementation. In 1984, StarLAN showed the potential of simple unshielded twisted pair by using category 3 cable - the same cable used for telephone systems. This led to the development of 10BASE-T (and its twisted-pair successors) and structured cabling which is still the basis of most commercial LANs today.

- Optical Fiber Cable

Today, optical fiber cables used for Internet are synonymous with speed, and are especially useful when transferring data over long distances. The fiber cable is made up of strands of incredibly thin optically pure glass that carry digital information with light instead of electrical currents used with Ethernet. 

There are two basic types of fiber optic cable: single-mode and multi-mode. 

• Single-mode fiber cables use laser light to send signals, and they are thinner than multi-mode fiber cables. Light-emitting diodes (LEDs) are used to send signals in multi-mode fiber cables, and multi-mode cables are usually used over short distances. Data transfer rates between 10 Mbps to 10 gigabytes per second (Gbps) are the norm.
• Single mode means the fiber enables one type of light mode to be propagated at a time. While multimode means the fiber can propagate multiple modes. The differences between single mode and multimode fiber mainly lies in fiber core diameter, wavelength & light source, bandwidth, color sheath, distance and cost.
• Both single-mode optics and multimode optics have their own features. Single-mode fiber cabling system is suitable for long-reach data transmission applications and widely deployed in carrier networks, MANs and PONs. Multimode fiber cabling system has a shorter reach and is widely deployed in enterprise, data centers and LANs. No matter which one you choose, on the basis of total fiber cost, choosing the one that best suits your network demands is an important task for every network designer.

- Interference

Ethernet cables are vulnerable to electromagnetic interference because they work through electrical signals. However, using a “shielded” cable can help minimize this problem. Because optical fiber cables work through the transmission of light, interference from electronic devices isn’t a concern.

- Security

Due to the way in which data is transmitted across Ethernet copper cabling, it is vulnerable to being intercepted. Ethernet switches can help improve security. Information sent via fiber optic cables is much more difficult to intercept because light can’t be read in the same way signals sent via copper cabling can be.

- Speed

Until recently, fiber Internet-optic cable speed would almost always beat Ethernet cable speed. But as the technology behind Ethernet cables has advanced, Ethernet cables can provide speeds as fast as some fiber optic cables. As mentioned, gigabit Ethernet can provide data transfer speeds of up to 1000Mbps, but through the use of Cat 6 cables it can support data transfer rates of up to 10Gbps. 

Typically, optical fiber transmits data faster than copper Ethernet cable and has the potential to be incredibly fast. In fact, a single optical fiber strand has been shown to transmit data at a rate of 100 terabits per second.

- Fire Threat

Although the voltage used by Ethernet cable is usually insufficient to cause a fire, there is always electricity present in Ethernet cables. Unlike Ethernet cable, optical fiber cable is non-flammable because it does not use electricity.

- Capacity and Bandwidth

Copper cabling strands are thicker than optical fiber strands, so less wires can be bundled in a 22 gauge copper cable than in a 22 gauge optical fiber cable. Additionally, Ethernet offers less bandwidth. For example, a Cat 6a cable can relay 600 MHz over 100 m, but a multi-mode optical fiber cable can relay 1000 MHz over the same distance.

[More to come ...]