CAT9 Ethernet. Fact or Fiction?

Introduction to CAT9 Ethernet

CAT9 Ethernet refers to the hypothetical next generation of Ethernet cabling that would theoretically support speeds up to 400 Gbps. While no official CAT9 standard currently exists, the designation refers to cabling and connectors anticipated to meet future high-speed network demands.

Ethernet standards have steadily evolved to support faster network speeds. The IEEE 802.3 working group has defined standards from the original 10 Mbps Ethernet (802.3i) to 400 Gbps Ethernet (802.3bs) and beyond. Each generation has increased the maximum signaling rate tenfold:

  • 10BASE-T – 10 Mbps
  • 100BASE-TX – 100 Mbps
  • 1000BASE-T – 1 Gbps
  • 10GBASE-T – 10 Gbps
  • 40GBASE-T – 40 Gbps
  • 100GBASE-T – 100 Gbps

As speeds have increased, new CAT levels have been specified to support the higher bandwidths. CAT9 would be the next proposed cabling standard to support the jump to 400 Gbps speeds and beyond.

However, CAT9 remains a hypothetical concept rather than established standard for now. The cabling specifications, connectors, and real-world performance are still undefined. Work is ongoing within standards bodies to determine what CAT9 could entail.

Higher Speeds

CAT9 Ethernet cables are theoretically capable of much higher speeds than previous Ethernet versions. While CAT6 cables max out at 10Gbps, CAT7 at 40Gbps, and CAT8 at 40-100Gbps, CAT9 has a theoretical maximum speed of 400Gbps [1]. This massive increase is enabled by changing from CAT8’s 2000MHz bandwidth to CAT9’s theoretical 6000MHz bandwidth. Such high speeds would allow for lightning fast file transfers and high bandwidth applications.

However, it’s important to note that these maximum speeds have not yet been achieved in real-world CAT9 implementations. The CAT9 specification is still under development and cables marketed as “CAT9” today typically max out at speeds comparable to CAT8. But the potential for up to 400Gbps shows the promise of this new standard for future high-speed networks.

Backwards Compatibility

CAT9 is designed to be backwards compatible with previous Ethernet standards like CAT5e, CAT6, and CAT6a. This means that CAT9 cables and ports will work with older Ethernet equipment.

According to Optcore (, “Like all other Ethernet cables, Cat8 uses RJ45 connectors and is backward compatible.” So while CAT9 pushes the boundaries of Ethernet speeds, it retains the RJ45 connectors used by previous standards.

CAT5e cables are only rated for speeds up to 1Gbps, and CAT6 cables support up to 10Gbps. But a CAT9 cable will be able to connect to CAT5e and CAT6 ports or cables and automatically downgrade to match those lower speed limits.

This backwards compatibility ensures that CAT9 cables and ports will work seamlessly with existing Ethernet networks and hardware. Users won’t have to upgrade their entire network infrastructure to take advantage of CAT9’s faster potential speeds. They can gradually update to CAT9 components over time, while maintaining connectivity with older equipment.

Use Cases

CAT9 ethernet cables are likely to be used primarily in high-performance networks where extremely fast speeds and low latency are required, such as enterprise data centers, financial trading networks, scientific computing clusters, and telecom infrastructure (Wirefaren). The higher bandwidth offered by CAT9 will enable new applications and workloads like high-resolution video, VR/AR, real-time analytics, and complex modeling and simulations.

CAT9’s ability to support speeds up to 400 Gbps will make it well-suited for connecting servers, switches, and routers across short distances within data centers. As network requirements continue to grow, CAT9 provides the headroom needed to scale bandwidth-hungry applications. Major cloud providers and hyperscale data centers are expected to be early adopters of the CAT9 standard.

While unlikely to show up in home networks or small office settings initially, CAT9 will gradually make its way into more mainstream enterprise infrastructure as its costs come down over time. The backwards compatibility of CAT9 with previous Ethernet standards also makes smooth future upgrades easier.


While CAT9 Ethernet has the potential to deliver speeds up to 400 Gbps, there are several challenges to developing and implementing this new standard (source):

One major challenge is the technical difficulty of reaching the theoretical maximum speeds. As speeds increase with each new Ethernet standard, it becomes more difficult to maintain signal integrity over long cable runs due to interference and attenuation. CAT9 will require advanced shielding and cabling techniques to reliably achieve 400 Gbps over 100 meters.

Upgrading to CAT9 will also be very costly for both manufacturers and consumers. New CAT9 cables, connectors, and network switches will need to be developed and installed to replace existing CAT5, CAT6, and CAT8 infrastructure. For many organizations, a full upgrade may not provide enough value to justify the expense (source).

Finally, upgrading will require replacing the entire network backbone. CAT9 cables and hardware will need to be used throughout the network to realize the full speed benefits. Partial upgrades or mixing with older cabling may result in bottlenecking or other issues. For large organizations, replacing miles of legacy cabling can be prohibitively disruptive and expensive.

CAT9 in the Real World

Although CAT9 Ethernet cables are not yet an official standard, some cable manufacturers have started producing cables marketing them as “CAT9.” However, adoption of these early CAT9 cables remains extremely limited.

According to experts, CAT9 Ethernet cables are unlikely to be formally standardized or see meaningful adoption for at least another 5-10 years. As this article explains, the current CAT8 standard already provides more than enough bandwidth (40Gbps) for most applications, so there is little need for even faster CAT9 cables in the near future.

Some analysts predict that 40Gbps will remain the mainstream standard through 2030, with 100Gbps CAT9 cables only being required in niche, high-bandwidth settings like data centers. Widespread CAT9 adoption likely won’t occur until 50Gbps or 100Gbps Ethernet comes into use for more mainstream business and consumer applications.

In summary, while early CAT9 cables can be purchased today, they remain very niche products. The lack of an official CAT9 standard means these cables may not even meet the specifications eventually approved. For now, CAT6, CAT6a, and CAT8 cables continue to dominate the market and meet most users’ needs.


While CAT9 Ethernet cable doesn’t yet exist, there are other ways to achieve the high speeds it aims to provide. Two popular alternatives are fiber optic cables and twinaxial (twinax) cables.

Fiber optic cables use light instead of electricity to transmit data and can provide speeds up to 100 Gbps for single-mode fiber and 10 Gbps for multi-mode fiber. Fiber optic cables are ideal for long distance runs between buildings or cities. The downside is that fiber optic cables and compatible hardware tend to be more expensive than copper cables (Source).

Twinax cables use two shielded coaxial cables and can support speeds up to 10 Gbps. They are meant for shorter distances than fiber optic but longer than copper Ethernet. Twinax cables provide high speeds and noise reduction at a lower cost than fiber, making them popular for high speed connections between equipment within a data center (Source).

For many home and office settings, CAT6 or CAT6a Ethernet provides sufficient speeds up to 10 Gbps. Higher end routers and network cards that support link aggregation can bond multiple Ethernet cables together for increased throughput. But for longer distances or very high speed backbones, fiber optic and twinax present proven solutions without waiting for a future CAT9 standard.

The Future

There has been a lot of speculation about whether CAT9 Ethernet cables will ever go mainstream. CAT9 has been in development for over a decade, with the goal of supporting speeds up to 100 Gbps. However, CAT9 has faced numerous delays and challenges.

The biggest roadblock for CAT9 is that many experts believe there is not a strong need for such high speeds among most users currently. Ethernet speeds have increased rapidly, going from 10 Mbps on CAT3 to 10 Gbps on CAT6A in just decades. However, average home internet speeds still tend to max out below 1 Gbps. Even in data centers and enterprises using cutting edge tech, 25-50 Gbps speeds can still suffice for most applications today. Given the costs involved, CAT7 and CAT8 appear sufficient for the near future needs.

This means CAT9 may firmly remain in the realm of specialized networks that truly require 100 Gbps transmission. Widespread commercial deployment would likely only come once internet speeds commonly reach about 50 Gbps in homes and businesses. At the current pace of progress, that could still be 5-10 years away.

That said, research and development continues on CAT9 and beyond. Once bandwidth needs finally catch up, having next-gen standards already in place will help the industry quickly scale up. When CAT9 eventually does arrive, it will likely skip traditional copper wiring and use shielded foiled twisted pair cabling for optimal protection from interference at extremely high frequencies. This infrastructure upgrade is another limiting factor holding CAT9 back.

Looking beyond CAT9, early research is underway on CAT10, CAT11, and beyond. However, any standards beyond CAT9 remain firmly in the realm of speculation and prototypes. Real-world deployment would likely not happen until at least the late 2020s or 2030s. With internet speeds still steadily increasing, the march towards higher ethernet standards will continue. But CAT9 and beyond will need to find more compelling real-world use cases first.

In summary, CAT9 and beyond face an uphill battle for mainstream adoption currently. But with internet speeds rising exponentially, their time will eventually come once there is truecommercial demand for such extreme ethernet cabling performance. The standards will be waiting and ready to scale up networks to keep pace.


In summary, while CAT9 Ethernet cables and ports have been developed to support speeds up to 2000 Mbps, they have not yet been standardized or broadly adopted. The main takeaways are:

  • CAT6 and CAT6a Ethernet are still the most common cable standards used today, supporting speeds up to 10 Gbps.
  • CAT8 Ethernet offers future-proofing for networks up to 40 Gbps but has limited real-world usage so far.
  • CAT9 offers theoretical speeds up to 2000 Mbps but no standards or certifications yet exist.
  • High prices and lack of interoperability make CAT9 impractical for most networks currently.
  • New Wi-Fi standards like Wi-Fi 6 offer multi-gigabit speeds without new cabling for many consumer applications.
  • As higher speed needs arise, CAT8 and optical fiber will likely scale up before CAT9 cables become standardized.

For most home and business users, CAT6/6a provides more than enough capacity for the foreseeable future. Overall, while CAT9 remains an emerging technology, it has yet to fully arrive as a practical Ethernet solution.


This article was written based on the author’s expertise and research into Ethernet cabling standards. However, the following sources were valuable in providing additional information:

  • IEEE 802.3 standards for Ethernet cabling
  • Product data sheets from Ethernet cable manufacturers
  • Technology forum discussions on high speed Ethernet cabling
  • IT networking blogs discussing CAT8 and CAT9
  • Wikipedia page on twisted pair cabling standards

As this was an overview article on CAT9 Ethernet, detailed citations were not included. However, the sources above provided useful background information.

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