Cat8 Cable Explained
Jul 15, 2023
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1. Preface
Why we need the Cat8 cable? Let me explain the reason.
With the development of technology and the increasing demands of people, high-speed transmission is required for everything, especially in data centers. Data centers are mainly composed of Main Distribution Area (MDA), Horizontal Distribution Area (HDA), and Equipment Distribution Area (EDA). In addition, there are also Access Areas and Zone Distribution Areas (ZDA). The specific situation of each area is shown in the diagram below:
Most high-density data center fiber cabling systems adopt plug-and-play, high-density, and scalable pre-terminated fiber cabling solutions. With the increasing concentration of network equipment in data center facilities, such as blade servers, core switches, and storage network switches, the port density continues to increase. If traditional cabling products are used, they will occupy a significant amount of effective space in the data center cabinets. Due to the length limitation of Cat 8/Class I and Class II channels being 30 meters, it is mainly applied in data centers where full 100-meter traditional cabling is not required. Backbone cabling and horizontal cabling may also be used in regular enterprise buildings. The backbone distance in many buildings is less than 30 meters, and many indoor access points do not require long cables. It can be foreseen that the speed of access points will exceed 10 Gbit/s in the future, so better cabling than CAT6A is needed to achieve the interconnection between access areas, Main Distribution Area (MDA), and Horizontal Distribution Area (HDA). Therefore, "CAT8" has become the primary choice for future cabling. As we enter the second half of the year 2023, according to information from the supply chain, the B2B Wholesale order volume of many CAT8 cable manufacturers has already increased significantly, such as COBTEL.
2. What is Cat8 Ethernet Cable?
Cat8 Ethernet cable, also known as Category 8 cable, is the latest generation of double-shielded (SFTP) network cables. It consists of two pairs of wires and supports a bandwidth of up to 2000MHz, enabling transmission speeds of up to 40Gb/s. In addition, Cat8 cables are compatible with all RJ45 cables, making them specifically designed for 25/40GBASE-T applications. However, they have a shorter transmission distance of only 30 meters, making them particularly suitable for connecting servers, switches, patch panels, and other equipment in short-distance data center environments.
2.1 Standards for Cat8 Ethernet Cable
The standards for cabling testing are defined in a separate set of standards. The TIA 1152-A standard was approved in the fall of 2016 and specifies the parameters and accuracy required for structured cabling certification based on the ANSI/TIA Cat8 performance category. The corresponding IEC 61935-1 5th edition standard, to be approved in the fall of 2017, defines the parameters and accuracy required for structured cabling certification based on the ISO/IEC performance category up to Class II. It also differentiates the accuracy limits between Class I and Class II when testing at the 2000MHz frequency.
These two standards define how to test the cabling components from CAT5E to CAT8.2 and the accuracy required within the 2GHz frequency range.
2.2 The categories of Cat8 Ethernet Cable
In the ISO/IEC 11801 standard, Cat8 Ethernet cables are classified into Class I and Class II based on channel levels. Class I Cat8 cables have shielding types such as U/FTP and F/UTP, and they are backward compatible with RJ45 connector interfaces of Cat5e, Cat6, and Cat6a. Class II Cat8 cables have shielding types such as F/FTP or S/FTP and are backward compatible with TERA or GG45 connector interfaces.
2.3 Currently, connector modules that support Cat8 Ethernet cables
include Cat8 (ANSI/TIA)/8.1 (ISO/IEC) connector modules with RJ45 interfaces and Cat8.2 (ISO/IEC) connector modules with "non-RJ45" interfaces such as TERA, ARJ45, GG45, and MMCPRO. These modules can be used to build structured cabling with a bandwidth of up to 2000MHz, supporting 25/40GBASE-T (IEEE 802.3bq) applications.
2.4 Mainstream Testers Supporting CAT8 Ethernet Cable Testing
Currently, the mainstream testers that support CAT8 Ethernet cable testing include FLUKE DSX-8000, JDSU Certifier40G, and WireXpert 500. Among them, WireXpert 500 is the only 500MHz CAT6A/Class EA tester that can be upgraded to support CAT8 Ethernet cable and Class I and Class II certification testing. To ensure testing accuracy, the instrument needs to be returned to an authorized service center for upgrading. Softing will perform the necessary upgrade steps and complete the factory calibration at 2500MHz.
2.5 Advantages of Cat8 Ethernet Cable
As mentioned above, the Cat8 Ethernet cable can share the RJ45 port, which means it can easily upgrade network speeds from 1G to 10G, 25G, and 40G. In addition, Cat8 cables are plug-and-play and can be field-terminated like other cable categories, making them easy to deploy. Furthermore, due to the low cost of Ethernet cables, twisted pair cables have always been the most cost-effective solution in Ethernet networks, and Cat8 cables are no exception. Therefore, when deploying 25G/40GBASE-T networks, Cat8 cables are more cost-effective than fiber optic patch cords for transmission distances shorter than 30 meters, and when the transmission distance is less than 5 meters, using Cat8 cables can save more costs compared to high-speed cables.
2.6 Differences between Cat8 Ethernet Cable and Cat5e, Cat6, Cat6a, and Cat7/Cat7a Ethernet Cables
Currently, there are five common types of cables in the market: Cat5e, Cat6, Cat6a, Cat7, and Cat7a. So, what are the differences between the Cat8 Ethernet cable and these cables? The table below shows the parameters of these cables:
From the table above, it can be seen that Cat8 Ethernet cable, like Cat7/Cat7a cable, belongs to the shielded twisted pair category and can be applied in data centers and high-speed, high-bandwidth environments. Although the transmission distance of the Cat8 cable is not as long as that of the Cat7/Cat7a cable, its speed, and frequency far exceed those of the Cat7/Cat7a cable. The differences between Cat8 Ethernet cable and Cat5e, Cat6/Cat6a cables are significant, mainly in terms of speed, frequency, transmission distance, and applications.
2.7 Applications of Cat8 Ethernet Cable
Backbone Cabling:
Since the length limitation of CAT8 Ethernet cable/Class I and Class II channels is 30m, it is mainly used in data centers without the need for traditional 100m full cabling. Backbone cabling and access point cabling may also be used in conventional corporate buildings. Many buildings have backbones that are less than 30 meters, and many indoor access points do not require long cables. It can be foreseen that the speed of access points will surpass 10Gbit/s in the future, requiring better cabling than CAT6A.
For households, certain applications may also act as catalysts for high-speed structured cabling. The typical length of cabling in homes is roughly the same as that in data centers, so CAT8 Ethernet cable may also become a future-oriented cabling choice for homes. Especially in terms of sustainability, home cabling is long-term or permanent, and pre-installing CAT8 cables is an excellent choice.
2.8 Cat8 Ethernet Speed:
The most common application is 40GBase-T. IEEE has made a relatively new move, 25GBase-T Ethernet speed. It turns out that 25GBase-T actually finds more supporters than 40GBase-T. One reason is cost, as the transceivers for 25GBase-T have lower production costs than those for 40GBase-T. Another reason is speed aggregation. In data centers, the next higher speed is 100Gbit/s Ethernet, typically over fiber optic cabling. Aggregating 4 x 25Gbit/s into a 100Gbit/s link is easier than aggregating 40Gbit/s into a 100Gbit/s link.
Currently, CAT8 Ethernet cables have received high attention from major carriers and manufacturers, providing a cost-effective transmission medium for network infrastructure. With the rapid changes in the network information age, CAT8 cables have excellent market prospects. CAT8 Ethernet cables can meet the public's demands for efficient transmission and stable signals. As the demand for transmission performance continues to rise among the general population, Cat8 cables will gradually become the primary equipment cabling for short-distance transmission.
3. Introduction to Cat5E/Cat6/Cat6a/Cat7 Cables, and the comparison with Cat8 cables.
3.1 What is Cat5e Ethernet Cable?
Cat5e (Category 5e) is the cheapest but slowest option. It supports data transfer speeds of up to 1 gigabit per second (Gbps), a frequency of 100 MHz, and a maximum length of 328 feet. It reduces crosstalk between the wires in the cable, thereby reducing the chance of interference and transmission errors. While it provides strong performance for most applications today, Cat5e offers fewer opportunities for future upgrades.
3.2 What is Cat6 Cable?
Cat6 cable, also known as Category 6 Ethernet cable, consists of four pairs of copper wires. It supports Ethernet connections up to 10 Gbps, and under normal conditions, it can achieve a maximum transmission speed of 1 Gbps within 100 meters. When transmitting at speeds of 10 Gbps, Cat6 cables support distances of 37-55 meters (depending on crosstalk), and they can transmit signals at frequencies of up to 250 MHz, which means the signals can travel through the cable at that frequency. Importantly, it uses the RJ-45 standard connector and is backward compatible with its previous versions like Cat5 and Cat5e.
3.3 What is Cat7 Cable?
Cat7 cable, also known as Category 7 Ethernet cable, supports high-speed Ethernet communication of up to 10 Gbps. Cat7 cable is backward compatible with Cat6, Cat5, and Cat5e cable categories. It utilizes shielded cables to provide a 100-meter, 4-connector channel and is designed for signal transmission at a frequency of 600 MHz.
Cat7 cables require fully shielded twisted pairs, known as Shielded Twisted Pair (SSTP) or Shielded Foiled Twisted Pair (SFTP) cabling, to completely eliminate external crosstalk and significantly improve noise resistance. Therefore, even with longer cables, higher speeds can be achieved.
3.4 Comparison of Cat6 vs. Cat7 vs. Cat8 Cables
Cat6 vs. Cat7:
In the comparison between Cat6 and Cat7, two important factors to consider are transmission frequency and cabling length.
Based on the information provided:
Transmission Frequency:
Cat6 cable provides performance of up to 250 MHz.
Cat7 cable has a rated transmission frequency of up to 600 MHz.
Cabling Length:
The maximum cabling length for Cat6 is 100 meters at 1 Gbps.
Cat7 also supports 100 meters but at 10 Gbps.
In terms of cable prices, Cat7 cables are generally more expensive than Cat6 cables under similar conditions. If neither is affordable, Cat5e is also a good choice for 10G networks.
By the way, the durability of Cat6 and Cat7 cables also differs. The estimated lifecycle of Cat6 cable is around 10 years, while Cat7 cable has a lifespan of approximately 15 years.
Cat7 vs. Cat8:
In the comparison between Cat7 and Cat8, transmission frequency and cabling length are also important factors.
Transmission Frequency:
Cat7 cable offers the performance of up to 600 MHz.
Cat8 cable provides performance of up to 2000 MHz.
Cabling Length:
The maximum cabling length for Cat7 is 100 meters at 10 Gbps.
Cat8 cable has a cabling length of 30 meters at 25 Gbps or 40 Gbps.
Regarding cable prices, Cat8 cables are more expensive than Cat7 cables due to the unique features that set them apart from previous Ethernet cables.
