10 GB Ethernet
10 GbE has recently caught the interest of network designers because of its promising potentials, but it’s not a new technology. It was launched way back in 2002, but because it was expensive and not compatible with previous standards, it was only used in a few large-scale networks. The consistent need for higher bandwidth propelled the 10 GbE to greater popularity recently. 10 GbE multiplies Gigabit Ethernet’s transmission speeds by a factor of 10. This has captured the interest of network designers in data centers, finance, defense, and healthcare industries, among others. Unlike the previous standards, 10 GbE operates in full-duplex mode and point-to-point links connected via switches. Its full-duplex mode is the main reason for the 10 GbE’s compatibility issues. The upgrade to 10 GbE typically requires changes in networking equipment. With that, not all Ethernet cables can work with 10 GbE. Here’s a guide on the Ethernet cables that will work with this Ethernet standard.
10 GbE Cables
Just like the previous standards, both copper and fiber optics cable can be used for 10 GbE networks. However, it can’t just be any copper and fiber optics cables because of the 10 GbE’s higher bandwidth requirements. There are two main types of 10 GbE networks which also determine the type of cable you need to use.
Fiber-Based 10 GbE
Fiber-based 10 GbE utilizes fiber optic cables. Fiber cables are optimal for 10 GbE because the faster speed of 10 GbE increases the amplitude loss or noise in copper cables, as distance increases. Fiber optics cables fall into two categories: Single-mode Fiber (SMF) and Multi-mode Fiber (MMF). Fiber optics cables use the SFP+ connectors, commonly used in 10 GbE switches, hubs, and other 10 GbE-compatible equipment.
SMF and MMF fiber cables differ in core diameter, bandwidth, wavelength, light source, and cost. The laser light follows a single path through the fiber in SMF cables, while in MMF cables, it follows multiple paths resulting in Differential Mode Delay (DMD). MMF has five generations of cables from OM1 to OM5. Differing in bandwidth and distance, each cable can run on for optimum performance. Currently, the maximum bandwidth supported by OM5 fiber is 28000MHz. On the other hand, SMF has a theoretically unlimited bandwidth because only one light mode passes through at a time. SMF has a smaller core diameter of 9 microns, while the MMF ranges from 50-62.5 microns. SMF’s smaller diameter makes it suitable for longer distances since there’s less signal distortion. SMFs can run as far as 10 km. In contrast, MMFs have higher signal distortion because of their larger core diameter making them ideal for shorter distances. The latest OM5 MMF can cover up to 400 m on a 10 GbE.
There are also standards relating to fiber-based 10 GbE published by IEEE 802.3, which use different types of fiber cables:
10GBASE-SR – uses an SPF+, multi-mode fiber cable with an 850 nm laser. This is the most common cable used in fiber-based 10 GbE. SR stands for “Short Range”, which can run up to 400 m depending on the generation of MMF.
10GBASE-LR – uses an SFP+, single-mode fiber cable with a 1310 nm laser. LR stands for “Long Range” since SMFs are known for covering up to 10 km of distance.
10GBASE-ER – also uses a single-mode fiber cable similar to 10GBASE-LR but can cover longer distances, thus the “Extended Range” stands for ER.
Copper-Based 10 GbE
When we say copper-based, twisted-pair cabling is what comes to mind, but 10 GbE also runs on twin-axial cabling and backplanes. 10BASE-T is a 10 GbE that makes use of twisted copper pair cables. Lower than Cat6 cables are typically not used on 10 GbE because of higher bandwidth and faster transmission requirements. Cat6 is not the most suitable for 10 GbE, but it still supports the standard, albeit on shorter distances maximizing at 55 meters. Cat6a is the better option with twice the frequency of Cat6 and delivering 10 Gbps of data up to 100 meters. Similarly, Cat7 cables are capable of supporting 10 GbE at 600MHz at a full 100 meters with reduced crosstalk because of their shielding. Newer switches with RJ45 interfaces are made available for Cat6 and Cat6a. Although these cables can still be used on SFP+ switches, it will require adapters at an additional cost.
Copper cables with SFP+ connectors, also known as Direct Attach Copper (DAC), are also out on the market for compatibility with SFP+ switches. 10GBASE-CR is an example of an SFP+ DAC 10 GbE cable and one of the most commonly used copper cables for 10 GbE. Double-twisted 10 GbE copper cable includes 10GBASE-CX4, 10GBASE-T, 10GBASE-KX4, and 10GBASE-KR supporting distances ranging 1 to 15 meters.
Conclusion
10 Gigabit Ethernet has a lot of standards under its umbrella, and it is not backward compatible with its predecessors. These often cause confusion on what cable to use. Although fiber and copper cables support 10 GbE, not all types can be utilized in this ultrafast Ethernet. Using an incorrect cable will greatly impact the network’s performance. Generally, the type of cable you need will depend on the type of network to be implemented. In summary, here are the different types of cables that best suit 10 GbE:
Multi-mode fiber cables – SFP+ fiber cables suitable for mid-range distances, reaching up to 400 m. For optimum performance, use OM3-OM5 cables.
Single-mode fiber cables – SFP+ fiber cables covering distances of up to 10 km.
SFP+ DAC – copper cables compatible with SFP+ interfaces, which are dominantly used in 10 GbE switches. Suitable for shorter distances, such as switches housed in the same rack or nearby racks.
10BASE-T – twisted pair cables Cat 6, Cat 6a, and Cat 7 for network infrastructures supporting RJ45 interfaces.
