10GBASE-T Cabling vs 10G SFP+ DAC, which one is better?

This post was updated on July 15, 2022

In 2022, 10GBASE-T and 10G SFP+ DAC have been widely used in data center cabling. They are two of the most popular options for short-reach copper cabling. But do you know which one is better? Which one will you prefer for your data center cabling? This post will discuss those topics and help you make a decision.

Table of Contents

Introduction
10GBASE-T Basics
10GBASE-T Cabling vs. SFP+ DAC Cable: What Are Their Differences?
Conclusion

Introduction

Some recent advances in information and data center technology are helping to drive demand for 10GbE architectures, including virtualization and server clustering, network convergence, and advanced storage architectures. The Internet is also a significant factor in the new forms of Internet-based information delivery and the explosive growth of digital and social media content.

For various reasons, 10GbE has become a flexible unified data center architecture. For 10Gb Ethernet (10GE) switches and NICs, 10GBASE-T, SFP+ fiber transceivers, and DAC cables have been widely used. Each technology has its advantages and disadvantages.

Compared with 10GBase-T, SFP+ DAC has certain advantages: lower delay, lower power consumption, lower cost, and the technology is now available and stable. 10GBase-T offers a range of benefits – familiarity, more extended reach, and structured cabling and patch panels. So, choose 10G SFP+ DAC or 10GBASE-T for network cabling? This article will discuss this topic.

There are three options for 10GbE interconnect for specific intended uses:

SFP+ DAC Cable: Direct attach copper cables are ideal for deploying blade chassis or 10GbE in racks over short distances. The transmission media is a Twinax cable.
Fiber Cabling: Fiber optic connections are suitable for high-traffic aggregate areas such as network backbones. The transmission media is a fiber cable.
10GBase-T Cabling: 10GBase-T cabling is the third choice for top-of-rack switches or end-of-row usage models. It’s based on the existing twisted-pair cabling infrastructure.

10GBASE-T Introduction

In the early days of Ethernet, several PHY standards, including various coaxial cable forms. Still, Ethernet was widely adopted only after running on twisted-pair cables and as a point-to-point rather than an unstructured loop.

It is practical to connect an Ethernet cable to each desktop next to the telephone line and set all connections in a wire cabinet. The connector for a twisted pair is an RJ45 connector. When Ethernet speed increases to 100 Mbps and then increases to gigabit speed, the same method is still maintained. Although cable requirements continue to evolve to maintain 100-meter distance standards, the primary way of using twisted-pair and RJ45 connectors remains the de facto standard.

10GBase-T requires a newer Cat 7 or Cat 6A up to 100 meters but can work on shorter distance Cat 6, Cat 5E, or Cat 5 cables. 10GBASE-T cabling is backward compatible with 1G ports, which will still be used for IPMI and other low bandwidth devices. You can get a 10GBASE-T switch and connect everything you have. Used with 10G SFP+ DAC, it isn’t easy to find two ports that are adequate for all 10G and 1G devices.

10GBASE-T Cabling vs. SFP+ DAC Cable: What Are Their Differences?

Now let us compare 10GBASE-T Cabling vs. SFP+ DAC Cable. The below table shows the detailed 10GBASE-T cabling and SFP+ DAC cable difference.

Comparison	SFP+ DAC	10GBASE-T
Power Consumption	~0.1w	~2.5w
Latency	0.3ns	2.6ns
Backward Compatibility	No	Yes
Max Distance	Passive: 7m, Active: 15m	30m or 80m
Media Type	Twinax Cable	Cat6, Cat6a, Cat7, Cat8 Cable
Size	Bigger	Smaller
Application Scenarios	Legacy Ethernet cable-based network	Interconnected with top-of-rack switches and servers, Storage Network
Manufacturing complexity	Medium	Medium
Weight	Heavier	Lighter
Pricing	$	$$

10GBASE-T Cabling vs. SFP+ DAC Cable Comparison

#1 – Cost Comparison

The SFP+ DAC is a lower-cost alternative to fiber, but it can only reach 10 meters. It requires purchasing an adapter card and a new top-of-rack (ToR) switch topology. DAC Cables are much more expensive than structured copper channels and cannot be field terminated. This makes the DAC more expensive than 10GBASE-T.

Many networks now have Cat 6, or Cat 6a cabling installed, so they are ready for 10GBase-T. Any existing fiber can be reused for 10GbE. The new Cat 6 or Cat 6a cable can be added at a lower cost than direct-attached dual-axis copper or fiber multi-mode connections.

Finally, training and knowledge transfer costs can be reduced because IT personnel are already familiar with Ethernet technology and RJ-45 connectors. Because SFP+ DAC does not have the flexibility and longer distance of 10GBASE-T, it only applies to 10GbE short-distance cabling.

#2 – Latency Comparison

The 10GBase-T PHY standard uses block coding to enable data to pass through the cable without error. The block encoding requires reading the data block into the transmitter PHY, running a mathematical function on the data, and sending the encoded data over the link. The opposite happens at the receiving end. The standard specifies 2.6 microseconds for the transmit-receive pair, and the data block size indicates that the wait time cannot be improved by approximately 2.0 microseconds per link.

The SFP+ DAC cable uses simpler electronics without the need for code blocks. Typical latency is about 300 nanoseconds per link. By comparison, SFP+ DAC provides lower latency, but 10GBASE-T and SFP+ fiber cabling provide higher latency.

#3 – Distance Comparison

Use the latest Cat 6A or Cat 7 cable, 10GBase-T up to 100 meters. The standard has been designed to allow patch panels and jumper cables. The SFP+ DAC provides a maximum distance of 10 meters (about 33 feet) based on passive copper cable. There are no patch panels used with DACs.

#4 – Flexibility Comparison

SFP+ DAC is not backward-compatible with existing GbE switches and only used for 10GbE switches. Where rose, 10GBASE-T SFP+ is backward compatible with existing 1 GbE networks. Therefore, 10GBASE-T cabling offers the most flexibility and the lowest cost media.

Conclusion

The comparison shows that 10GBASE-T cabling and 10G SFP+ DAC have advantages and disadvantages. Generally speaking, SFP+ copper cable cabling is more suitable for data center applications, while 10GBASE-T cabling will be better for wiring closets because of its flexibility and cost.

After reading this post, I hope you understand the difference between 10GBASE-T cabling and 10G SFP+ DAC cable.

Now I would like to ask some questions.

Is your network based on 10GBASE-T or SFP+ DAC?
Are you optimistic about the future of 10GBASE-T?
Have you bought any 10G SFP+ DAC cables or 10GBASE-T transceivers?

Please leave a message and tell me your story.

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10GBASE-T Cabling vs. 10G SFP+ DAC, Which One is Better? (2022 Update)