10G Technology: 10GBASE-T Vs. SFP+

As the basis of upgrading network, 10G network has been ubiquitous in data center, enterprise network and even home networking. 10GBASE-T and 10G SFP+ are two different kinds of technology which transmit data via copper and fiber respectively. 10GBASE-T technology provides the most flexible and economical solution while 10G SFP+ offers the compatible and user-friendly solution for 10G Ethernet connectivity option. This article would shed light on the difference between 10GBASE-T and 10G SFP+.

10GBASE-T Technology

As the fourth generation of IEEE standardized Base-T technologies, 10GBASE-T is designed to reduce overall costs and improve flexibility. By using RJ45 connectors and unshielded twisted pair cabling, 10GBASE-T allows 10Mbps, 100Mbps, 1Gbps, and 10Gbps data transmission, while being backward-compatible with prior generations. Merits and demerits of using 10GBASE-T are listed in the below.

Pros of 10GBASE-T
  • Cheap twisted pair cables.
  • Patch panels can be used without messing around with transceivers.
Cons of 10GBASE-T
  • Higher power consumption.
  • People may get tempted to use substandard cabling, and this would have a negative influence on the speed.
  • No good way to extend length beyond 100m (though this can be somewhat mitigated by choosing switches with mostly 10GBASE-T but also a handful of SFP+ ports) limited choice of equipment.
10G SFP+ Technology

The 10G SFP+ transceiver meets the standard of Multi-Sourcing Agreement (MSA), and provides the cost effective solution for 10G optical data communication. It supports both duplex and simplex LC optics interfaces. The 10G SFP+ transceiver consists of 10Gbit/s DFB/EML optical transmitter and PIN receiver, which allow 300m~120km 10G Ethernet and 10G fiber channel applications. Advantages and disadvantages of using 10G SFP+ transceivers are listed in the below.

Pros of SFP+
  • Lower latency
  • Lower power consumption
  • Cheaper NICs and switches
  • More choice of connected equipment.
  • With transceivers and fiber basically any run length can be covered.
Cons of SFP+
  • Apparently, it is not a big deal for transmission within short distance.
  • For longer runs or runs that need to go through patch panels needs transceivers and fiber. Fiber itself is cheap but transceivers, termination, patch panels, and etc for fiber would cost a lot.
10GBASE-T Vs. SFP+

This passage would mainly demonstrate the difference between 10GbE base T and SFP+ options from the respective of technology, latency, and power consumption.

—Technology

Generally, 10GBase-T is cheaper and easier to deploy than the alternative SFP+ technologies. You can further compare these two different technologies in the following table:

Table1 Comparison between 10GBASE T and SFP Plus

—Latency

Low latency is paramount to ensure fast response time and reduce CPU idle cycles. That increases data center efficiency and ROI. With the increasing of using private cloud applications, the need for low latency is growing fast in large scale data centers.

When it comes to 10GBase-T, the PHY standard uses block encoding to transport data across the cable without errors. The standard specifies 2.6 microseconds for the transmit-receive pair, and the size of the block requires that latency to be less that 2 microseconds. SFP+ uses simplified electronics without encoding, and typical latency is around 300 nanoseconds (ns) per link. You can further compare them in the below table.

latency comparison

Basically, there are only slight differences between 10GBASE-T and SFP+ in terms of application latency. Relatively speaking, 10G SFP+ has lower latency than 10GBASE-T. High latency would exert negative influence on CPU and therefore limiting data center efficiency and increasing operational costs.

—Power Consumption

10GBase-T components today require anywhere from 2 to 5 watts per port at each end of the cable (depending on the distance of the cable) while SFP+ requires approximately 0.7 watt (regardless of distance). The difference is clearly shown in the below chart.

power consumption comparison

(Resource: http://www.datacenterknowledge.com)

Conclusion

Through this article, we are clear about the pros and cons of 10GBASE-T and SFP+ as well as their differences in technology, application latency and power consumption. It is evident that SFP+ is the right technology to ensure optimal performance with lowest latency and lower power usage in the data center. The cost saving becomes obvious when deploying from 1000 to 10,000 cables in the data center.

Three Media Options for 10GbE in Data Centers

With the added network infrastructure complexity, power demands, and cost considerations, 10 Gigabit Ethernet (GbE) comes to network administrators’ thinking point. While 1GbE connection is able to handle the bandwidth requirements of a single traffic type, 10GbE has been preferred as the ideal solution by customers to meet current and future input/output (I/O) demands. Delivering more bandwidth, 10GbE simplifies the network infrastructure at the same time by consolidating multiple gigabit ports into a single 10gigabit connection.

Generally speaking, there are three media options for 10GbE: 10GBASE-CX4, SFP+, and 10GBASE-T. Each option has its own virtual point and downside in terms of cost, power consumption and distance reach. This paper analyzes these three options respectively, helping you understanding the pros and cons of current 10GbE media options.

10GBASE-CX4

10GBASE-CX4 was the first 10G copper standard published by 802.3 (as 802.3ak-2004), an early favorite standard for 10GbE deployments. Using the XAUI 4-lane PCS (Clause 48) and copper cabling similar to that used by InfiniBand technology, 10GBASE-CX4 is able to reach 15 meters. Practically, this option is limited by its heavy weight and expensive cables. In addition, the size of the CX4 connector prohibited higher switch densities required for large scale deployment. Larger diameter cables are purchased in fixed lengths, causing problems in managing cable slack. What’s more, the space isn’t sufficient to handle the larger cables.

10GBASE SFP+

SFP+ fiber optic cables and SFP+ direct attach cables (DACs) are all better solution than CX4.

10GBASE SFP+ Fiber Optic Cables

10GBASE-SR, 10GBASE-LR, 10GBASE-LRM are all specified to work through fiber optic cables, such as JD094B (shown below). This HP 10GBASE-LR SFP+ transceivers takes fiber as its transmission medium with distance up to 10km. Really, great for latency and distance, but fibers are expensive. Although they offer low power consumption, the project of laying fiber networks in data centers is limited due to the cost of the electronics largely. The fiber electronics can be four to five times more expensive than their copper counterparts, meaning that ongoing active maintenance, typically based on original equipment purchase price, is also more expensive.

JD094B, HP 10GBASE-LR SFP+ transceiver

10GBASE SFP+ DAC

DAC can be classified in to direct attach copper cable and active optic cable (AOC). On the one hand, SFP+ DAC is a lower cost option alternative to fiber, with its distance reaching flexible in 1m (eg. SFP-10G-AOC1M), 2m, 3m, 5m, 7m and so on. On the other, SFP+ DAC is not backward-compatible with existing 1GbE switches. Besides, this solution requires the purchase of an adapter card and requires a new top of rack (ToR) switch topology. And the cables are much more expensive than structured copper channels, and cannot be field terminated. All these factors make SFP+ DAC less popular the 10GBASE-T which will be discussed soon.SFP-10G-AOC1M, for short reach

10GBASE-T

10GBASE-T, or IEEE 802.3an-2006, is a standard released in 2006 to provide 10Gbit/s connections over unshielded or shielded twisted pair cables with distances up to 100metres (330 ft). Due to additional encoding overhead, 10GBASE-T has a slightly higher latency in comparison to most other 10GBASE standards. What’s more, 10GBASE-T offers the most flexibility, the lowest cost media. And because of its backward-compatibility with 1000BASE-T, 10GBASE-T can be deployed based on existing 1GbE switch infrastructures that are cabled with CAT6 and CAT6A (or above) cabling, keeping costs down while offering an easy migration path from 1GbE to 10GbE.

Conclusion

The deployment of 10GbE infrastructure should be much easier, with these media options in mind, coupled with your own such project considerations as cost, power consumption and distance reach. Fiberstore, as a professional fiber optic product supplier, offers a broad selection of fiber and copper cables, including SFP-10G-AOC1M mentioned above. For more information about 10GbE media options, you can visit Fiberstore.