Choosing the right networking cable for enterprise uptime and speed 

A closer look at networking cables 

Dr. Carlos Berto Director of Network Engineering 

Brian Chang Technical Writer/Editor 

Although network cables play a significant role in a network, it can be overwhelming to pick up on all of the terminology in the cable ecosystem. In this article, let's dig away at the gamut of network cabling terms and explore their significance in network architectures.

Cable types

Network cables come in different shapes and sizes. They serve as physical links in a wide variety of configurations from home networks to data centers to telecom networks and more. 

Cables that are used in short-range deployments, such as your home internet or office setups, are typically referred to as “patch cables.” In long-range deployments, network cabling is referred to as structured cabling. 

There are three main types of networking cables: 

Coaxial

Coaxial cables (aka Coax) carry high-frequency electrical signals in cable television and broadband internet networks. This type of cable should be familiar to anyone who’s ever set up home internet or installed a TV. It’s that cable with a center pin which is fastened into the receptacle on the receiving outlet or cable.

A coax cable is heavily shielded to protect the inner cable from electromagnetic interference. With outbound data being sent via the inner conductor and inbound data received through the outer conductor, this creates a balance that cancels out electromagnetic emissions. Signal strength is a major advantage of Coax, which is why it continues to be widely used despite being an older cable variant.

Twisted pair

Twisted pair cables are some of the most commonly used cables worldwide. This is the type of cable that everybody uses for their home internet, but most people just refer to it as an Ethernet cable.

If you take a closer look at the unshielded part of an ethernet cable, however, you may be able to see wires (conductors) twisted together in pairs inside the cable. The wires are twisted together in order to “cancel out” electromagnetic interference and crosstalk, which increases the signal strength. 

There are two different types of twisted pair cables:

Unshielded twisted pair (UTP)

Unshielded twisted pair cables are far more common than a shielded cable as they do not require extra costs to shield the cable.

Shielded twisted pair

Although they offer higher signal strength protection than UTP cables, they are far less common due to their higher costs.

Fiber 

Fiber optics cables (or Fiber) are made from glass. When the word fiber is mentioned in the context of networking, you might associate the term with “fast internet” - and that idea is correct. Whereas coax or twisted pair cables carry data in the form of electrical pulses, fiber cables carry data via light. This makes it a much faster medium for data transfer and allows it to carry data over longer distances. 

As such, fiber is often the medium of choice in data center networking. The caveat is that fiber is generally more expensive to acquire, which is why service providers are relatively conservative on their fiber deployments. They limit fiber deployment to long distance sections of the network, while strictly using copper in the short distance or the more complex, dated “last mile” sections of a network infrastructure. 

Communication protocols

Ethernet

There is a common misconception that Ethernet is a type of cable. Instead, Ethernet is actually a network communications protocol, not the cable itself. Think of it as a set of rules that dictates how data is formatted and transferred over the cable.

Because Ethernet is the most commonly used standard for twisted pair cables, the term “Ethernet cable” and “twisted pair cable” are often used interchangeably, even if not all network cables are Ethernet-based.

Infiniband

Infiniband is an example of a type of communication protocol that falls outside of the Ethernet category. Infiniband utilizes a different set of rules for formatting and transferring data. For example, it uses RDMA to prevent packet loss in order to speed up data transfer and lower latency.

Cabling classifications

Types of twisted pair cables

The term “Cat6” or “Cat5e” cables should ring a bell for those who used wired internet. But what do these terms actually mean?

These terms make up part of the classification system for twisted pair cables. “Cat” stands for category and the number denotes the performance level of the cable, as shown in the following list:

*Listed for educational purposes only; Axiom carries Cat5e, Cat6, Cat6A, Cat8 cables

Types of fiber cables:

The fiber cable’s core size and the light propagation mode goes a long way into determining the speed and distance in which the data can be transferred. There are two different types of fiber cables with different core diameter sizes and light propagation modes: 

SMF Single mode fiber

Single mode fiber has a much narrower core diameter and only uses a single mode of light, as its name suggests. Although it may seem like single-mode fiber carries less data because of these characteristics, the opposite case is true. Data transfer on SMF is faster because the cladding and its narrow core diameter prevent light from escaping or dispersing. SMF also uses lasers as the light source, which allows the light signal to propagate further with minimal signal loss.

MMF Multimode fiber

Multimode fiber, on the other hand, has a much larger core diameter and sends multiple modes of light using LED as its light source. This results in weaker signal strength at farther distances as the light scatters and gets absorbed due to modal dispersion and attenuation. 

OM/OS Cables

The fiber equivalent to the Cat naming system for twisted pair cables is the OM/OS naming system.

OM (Optical Multimode) cables

OM cables are multimode cables. They utilize a similar classification system to Cat cables: the numbers denote the iteration of OM cables, with higher numbered cables as upgrades over the lower numbered cables. The first number in the sizing represents the core diameter and the second number represents the cladding diameter.

OS (Optical Single-mode) cables

OS cables are single-mode cables which utilize a similar classification system. All OS jackets are yellow-colored.

*Listed for educational purposes only; Axiom carries OS2 cables

Ethernet nomenclature

The term “BASE” or “GBASE” followed by letters and numbers is often thrown around in network discourse. This terminology is used for Ethernet standards and the nomenclature. “BASE” is used for sub 1G ethernet while “GBASE” is used for 1G or faster ethernet (Gigabit Ethernet).

The number preceding “GBASE” stands for the data rate. The letters after “GBASE” stand for the type of medium used and/or the network reach.

The letter T, which stands for Twisted Pair, indicates a copper standard. Variations of the letter R stand for network reach, which indicates a fiber standard. So for example, “100GBASE-T” refers to a 100Gbps copper standard. “100GBASE-LR” refers to a 100Gbps long-reach fiber standard.

Cables ports/connectors

Cables also differ greatly in how they connect to network equipment. Different types of equipment such as switches, routers, etc. have different types of ports. It’s important to understand which types of connectors are compatible with which types of ports.

Modern gigabit ethernet switches typically come with two types of cable ports for networking:

RJ45

The RJ45 (Registered Jack-45) connector is a universally recognizable type of connector that is used on the vast majority of Ethernet cables. Your standard Ethernet cable uses this connector and all Ethernet cables from Cat5 to Cat8 support RJ45 as well.

The term “RJ45” is somewhat of a misnomer as the connector is actually an 8P8C (8 Position 8 Contact) connector. The original RJ45s connector has a slight key cut on the side of it, but the name has tacked on so that everybody calls it the RJ45 connector for all intents and purposes.

RJ45 connectors are designed for copper cables only. For short distances, you can simply plug in an Ethernet cable terminated with RJ45 connectors (male) into the RJ45 ports (female) on opposing routers/switches. The maximum reach for a single-run Ethernet cable is 100m, however.

In longer distances, copper SFP (Small form-factor pluggable) transceivers are needed to extend the reach. Network operators can connect an RJ45 port on one switch to an SFP port on another switch by using an RJ45 copper SFP transceiver.

Optical fiber connectors

Because fiber is often more expensive, network providers will often blend fiber deployment with copper cabling/equipment to save costs. As a result, there will be a variety of network devices in which back-and-forth conversion between fiber and copper is needed to connect all the devices together.

This is where an SFP transceiver comes in handy. SFP transceivers convert electrical signals to optical signals and back, allowing network devices to interface with different types of mediums.

On the switch/router facing side, the transceivers are slotted into the SFP ports using the shape of the SFP itself as a connector. On the cable facing side of the SFP transceiver, the fiber cable uses different types of optical fiber connectors to connect to the transceiver. These connectors include:

Pre-assembled cables

Pre-assembled cables refer to cables that already have transceivers attached to them. These are typically designed for short distance connections between servers or in a data center.

DACs (Direct-Attach-Copper)

DAC transceivers come in pre-assembled lengths and are plug-in-play in most instances. Copper transceivers are attached at both ends of the cable.

AOCs (Active-Optical-Cables)

AOCs are the fiber equivalents of DAC cables as they have two optical transceivers attached to both ends of the cable.

Power your data center with Axiom network cables

Axiom offers a complete lineup of fiber and copper networking cables with the ability to customize cables for specific applications. We also offer TAA options for quality and compliance. Our cables delivery logistics system utilizes air options for overseas shipments to provide ultra-quick turnarounds and shorter lead times. We have fulfillment centers located all over North America, allowing us to ship within much closer proximity. To learn more about Axiom networking cabling, email: sales@axiomupgrades.com