Tag Archives: SFP+ DAC

10G Twinax vs Fiber: SFP+ Copper Cable or SFP+ SR Module?


Over the years, 10GbE has successfully stretch its reach from enterprise data centers to midmarket networks due to the increased bandwidth requirements and the growth of enterprise applications.   As the deployment of 10GbE is going boarder, it is important to understand how to effectively leverage the technology to better satisfy your network demand. Thus, all elements should be carefully reviewed to choose the appropriate cabling solution for your workloads. Many customers facing the problem to choose from 10G twinax vs fiber (SFP+ copper cable vs SFP+ SR) as both are viable options for short range. This is what we are about to figure out in this article.

10G Twinax vs Fiber: SFP+ DAC Cables Is Simple and Cost-Effective

10G twinax vs fiber for short reach connection? Before we go any further, it’s better to take a glimpse of what  SFP+ direct attach cable (DAC)are and what role they play. A SFP+ DAC cable, also known as SFP+ twinax copper cable, is effectively viewed as a transparent cable to the switch. It is a cable invented with each end physically resembling an 10g SFP+ transceiver, but with none of the expensive electronic components. Although being even more pricy than fiber optic cables, SFP+ Copper Cables effectively eliminate the expensive optical transceiver required in the equipment they connected.

10g twinax vs fiber - 10g dac

SFP+ Copper Cables comes to two different flavors: passive and active. Passive SFP+ Copper Cables requires little to no direct power to operate, and are extremely affordable with the length ranging from 0.5m all the way up to 7m. Active SFP+ Copper Cables integrates signal processing circuitry into its built-in connectors and actively powering those circuits with DC power provided by the switch. The circuitry in active sfp+ cable thus brings up the overall cost. This partly explains why active sfp+ cable is usually more expensive than its passive counterparts.

10G Twinax vs Fiber: SFP+ SR Is Flexible and Future-Proofing

For 10G twinax vs fiber, we cannot make our decisions until we clear knows each function. SFP+ SR are similarly used for short runs, and that is exactly “SR” stands for – short reach. SR transceivers are almost always multimode, and optimized for high speeds over relatively short distances. It operates at 850 nm, and can reach up to 300 m with laser-optimized OM3 and 400 m with OM4. The 10G SFP+ SR transceiver module offer a flexible connectivity option for data centers, enterprise wiring closets, and service provider transport applications. The price is the major issue that some customers turn to SFP+ Copper twinax cable instead of SFP+ SR transceivers for short runs, especially for those who are under tight budget. Fortunately, third-party optics has narrowed down the price gap by providing decent performance transceiver modules with only a fraction of the cost at the original ones.

10g twinax vs fiber - 10gbase sfp+ sr transceiver module

10G Twinax vs Fiber: Application Considerations

When choosing between 10G twinaxs vs fiber, the following factors have to be well considered.

10g twinax vs fiber - 10g direct attach cable dac vs 10g sfp+ sr module

Distance: Advocators of SFP+ twinax copper cable  insist that, if distance is not a problem, they tend to choose SFP+ cable  because of the lower power needs and lower latency it provides, and the power saving alone is significant. Not to mention that the cable itself is less fragile and more durable. As SFP+ twinax cable  only reach up to 10m, when distance happens to be a factor, SFP+ SR transceiver can get much longer reach and more compatibility anyway. Or if the switches are connected via patch panel, then your hand is forced to 10G SFP+ SR transceiver and fiber. To sum it up, SFP+ cables are used within the rack to connect servers and storage to ToR switches, it is an “intra-rack” thing, whereas SFP+ SR in for connection between racks – known as “inter-rack” cabling.

Cable management: in terms of managing cables, fibers are believed easier to work with – it has no limit of cable length as with SFP+ cables. As for bulky and thick SFP+ cables it is fine for same rack FEX extension or one or two servers, but load half a rack with a top of rack FEX/switch with twinax, you will have mass of inflexible copper at the back of the rack. And that can be a nightmare.

Cost: 10G optical transceivers are much expensive than 10G SFP+ copper cable – these might be the driven course for people using twinax over SR optics. However, the booming of third party optics well addressed the issue by providing full compatible and trustworthy transceiver modules, which on the other hand, significantly reduces the cost of optics. Since the price gap between SFP+ cables and SR SFP+ optics is reduced, it bestowed customers more chances to weight other affecting factors.

Uniformity: users prefer to use SFP+ SR when working with different vendors, it’s less likely to run into issues if you use optical transceivers. Truly, SFP+ SR indeed makes multi-vendor environment cabling much easier: imagine that you have to connect two switches from different vendor, simply use two SR transceivers that compatible with each brand switch can well solve the problem. However, if cost really matters, you can equally choose this special made SFP+ twinax cable from FS – different brands can be made at each ends, which are compatible with the major vendor on the market.

fs 10g dac twinax cable


10G twinax vs fiber, from a network perspective, the SFP+ twinax cable is fine and a lot cheaper for very limited short runs – typically intra rack cabling, while for mass adoption, they become absolutely thick and unmanageable. So it’s worth the savings if your switch is in the same rack as the equipment you are connecting, and if it goes to another rack, SFP+ SR with fiber and a patch panel can be a sound option. With SR optics, you have much more flexibility in the placement of servers and how you lay out your racks. It is the obvious choice once the demand for bandwidth and length becomes more acute and cable management and future growth becomes critical.

Related Articles:

SFP+ Direct Attach Copper Twinax Cable Deployment Considerations

SFP+ cable vs 10GBASE-T

Unique Advantages of 10GBASE-T in Migrating Data Center to 10GbE

Over the last decade, large enterprises have been migrating data center infrastructures from 100MB Ethernet to 1/10 Gigabit Ethernet (GbE) to support high-bandwidth, mission critical applications. However, many mid-market companies found themselves restricted from this migration to 10GbE technology due to cost, low port density and high power consumption. For many of these companies, the explosive growth of technologies, data and applications is severely taxing existing 1GbE infrastructures and affecting performance. So it’s high time for them to upgrade the data center to 10GbE. With many 10GbE interfaces options such as CX4, SFP+ Fiber, SFP+ Direct Attach Copper (DAC), and 10GBASE-T offered, which one is the best? In fact, the answer is 10GBASE-T.

SFP+ , SFP+ Direct Attach Copper (DAC), and 10GBASE-T

Shortcomings of SFP+ in 10GbE Data Center Cabling
SFP+ has been adopted on Ethernet adapters and switches and supports both copper and fiber optic cables makes it a better solution than CX4, which is the mainstream 10GbE adoption today. However, SFP+ is not backward-compatible with the twisted-pair 1GbE broadly deployed throughout the data center. SFP+ connectors and their cabling were not compatible with the RJ-45 connectors used on 1GbE networks. Enterprise customers cannot just start adding SFP+ 10GbE to an existing RJ-45 1GbE infrastructure. New switches and new cables are required, which is a big chunk of change.


Advantages of 10GBASE-T in 10GbE Data Center Cabling
10GBASE-T is backward-compatible with 1000BASE-T, it can be deployed in existing 1GbE switch infrastructures in the data centers that are cabled with CAT6, CAT6A or above cabling. As we know, 1GbE is still widely used in data center. 10GBASE-T is backwards compatible with 1GbE and thus will become the perfect choice for gradual transitioning from 1GbE deployment to 10GbE. Additional advantages include:

  • Reach
    Like all BASE-T implementations, 10GBASE-T works for lengths up to 100 meters giving IT managers a far-greater level of flexibility in connecting devices in the data center. With flexibility in reach, 10GBASE-T can accommodate either top of the rack, middle of row, or end of the row network topologies. This gives IT managers the most flexibility in server placement since it will work with existing structured cabling systems.
  • Power
    The challenge with 10GBASE-T is that even single-chip 10GBASE-T adapters consume a watt or two more than the SFP+ alternatives. More power consumption is not a good thing in the data center. However, the expected incremental costs in power over the life of a typical data center are far less than the amount of money saved from reduced cabling costs. Besides, with process improvements, chips improved from one generation to the next. The power and cost of the latest 10GBASE-T PHYs will be reduced greatly than before.
  • Reliability
    Another challenge with 10GBASE-T is whether it could deliver the reliability and low bit-error rate of SFP+. This skepticism can also be expressed as whether the high demands of FCoE could be met with 10GBASE-T. In fact, Cisco has announced that it had successfully qualified FCoE over 10GBASE-T and is supporting it on its newer switches that support 10GBASE-T in 2013.
  • Latency
    Depending on packet size, latency for 1000BASE-T ranges from sub-microsecond to over 12 microseconds. 10GBASE-T ranges from just over 2 microseconds to less than 4 microseconds, a much narrower latency range. For Ethernet packet sizes of 512B or larger, 10GBASE-T’s overall throughout offers an advantage over 1000BASE-T. Latency for 10GBASE-T is more than 3 times lower than 1000BASE-T at larger packet sizes. Only the most latent sensitive applications such as HPC or high frequency trading systems would notice any latency.
  • Cost
    When it comes to capital costs, copper cables offer great savings. Typically, passive copper cables are two to five times less expensive for comparable lengths of fiber. In a 1,000-node cluster, with hundreds of required cables, that can translate into the hundreds of thousands of dollars. Extending that into even larger data centers, the savings can reach into the millions. Besides, copper cables do not consume power and because their thermal design requires less cooling, there are extensive savings on operating expenditures within the data center. Hundreds of kilowatts can be saved by using copper cables versus fiber.

The 10GbE standards are mature, reliable and well understood. 10GBASE-T breaks through important cost and cable installation barriers in 10GbE deployment as well as offering investment protection via backwards compatibility with 1GbE networks. Deployment of 10GBASE-T will simplify the networking transition by providing an easier path to migrate to 10GbE infrastructure in support of higher bandwidth needed for virtualized servers. In the future, 10GBASE-T will be the best option for 10GbE data center cabling!

Three Types Physical Media Systems For 10 Gigabit Ethernet


Dramatic growth in data center throughput has led to the increasing usage and demand for higher-performance servers, storage and interconnects. As a result, we are seeing the expansion of higher speed Ethernet solutions, specifically 10 and 40 gigabit Ethernet. This text will take an overview of 10 gigabit ethernet as well as introducing some common 10-gigabit physical media systems: fiber optic media systems, DAC cable media systems and twisted-pair media systems.

Introduction of 10 Gigabit Ethernet

10 Gigabit Ethernet is a group of computer networking technologies for transmitting Ethernet frames at a rate of 10 gigabits per second. It was first defined by the IEEE 802.3ae-2002 standard. Unlike previous Ethernet standards, 10 Gigabit Ethernet defines only full duplex point-to-point links which are generally connected by network switches. Like previous versions of Ethernet, 10GbE can use either copper or fiber cabling. However, the 10 Gigabit Ethernet standard encompasses a number of different physical layer (PHY) standards. A networking device may have different PHY types through pluggable PHY modules, such as those based on XENPAK, XFP and SFP+.

Classification of 10 Gigabit Ethernet

When comes to 10 gigabit Ethernet (10GbE), IT managers are now faced with the challenge of selecting the appropriate 10-gigabit physical media. Broadly, this media is usually offered in the following three categories:

10 Gigabit Ethernet Fiber Optic Media Systems Solution

There are two classifications for optical fiber: single-mode (SMF) and multimode (MMF). SMF is used for long distance communication and MMF is used for distances of less than 300 m. There are also active optical cables (AOC). These have the optical electronics already connected eliminating the connectors between the cable and the optical module. They plug into standard optical module sockets. They are lower cost than other optical solutions because the manufacturer can match the electronics to the required length and type of cable. AOC Cable provides very short distance (same shelf) inexpensive connectivity at 10G rates between two 10G data ports. The following picture shows the SFP+ active optical cables (AOC):


NOTE: Dramatically reducing 10G interconnectivity costs, the 10G cables can provide inexpensive and reliable 10G speed connections using either copper cables with distances reaching up to 15 meters or active optical cables reaching even 100 meters.

10 Gigabit Ethernet Copper Direct Attach Cable Media Systems (10GSFP+Cu) Solution

SFP+ direct attach cable (DAC), also known as 10GSFP+Cu, is a copper 10GBASE Twinax Cable which comes in either an active or passive twinax cable assembly and connects directly into an SFP+ housing. SFP+ direct attach cable has a fixed-length cable, typically 1 to 7 m (passive cables) or up to 15 m (active cables) in length. And like 10GBASE-CX4, is low-power, low-cost and low-latency with the added advantages of using less bulky cables and of having the small form factor of SFP+. Besides, SFP+ direct attached Twinax copper today is tremendously popular, with more ports installed than 10GBASE-SR. The following picture shows the SFP+ passive direct attach cable(DAC):

passive SFP+ cable

10 Gigabit Ethernet Twisted-Pair Media Systems (10GBASE-T) Solution

10GBASE-T is a standard released in 2006 to provide 10 Gbit/s connections over unshielded or shielded twisted pair cables, over distances up to 100 metres. 10GBASE-T cable solution can also be used for 1000BASE-T allowing a gradual upgrade from 1000BASE-T using auto negotiation to select which speed to use. 10GBASE-T uses the IEC 60603-7 8P8C (commonly known as RJ45) connectors already widely used with Ethernet. Transmission characteristics are now specified to 500 MHz. To reach this frequency Category 6A or better balanced twisted pair cables are needed to carry 10GBASE-T up to distances of 100m. The following picture shows the Category 6A cable:

Cat 6a cable