标签归档:10G SFP+

Things You Should Know About SFP+ Transceiver

SFP+ transceiver in short stands for enhanced Small Form-factor Pluggable transceiver. As an enhanced version of SFP, the SFP+ transceiver is also a compact, hot pluggable optic module transceiver. The SFP+ can be used for telecommunications and data communication applications. With various standards, the SFP+ transceiver can be classified differently. In this text, we mainly focus on the SFP+ transceiver’s host interface, data rate, application, and distance.

Types of SFP+ Transceiver

Classified by host interface, the SFP+ fiber optic transceiver can be divided into linear and limiting transceivers. The linear SFP+ module is most appropriate for 10GBase-LRM; otherwise, a limiting module is preferred with the reason that it contains a signal amplifier to re-shape the degraded (received) signal whereas linear does not.

Classified by data rate, the SFP+ transceiver can still be put into three types: 8.5Gb/s SFP+, 10Gb/s SFP+, 16Gb/s SFP+. With its fast development, many vendors can provide a customized one to meet their customers’ different demands.

Classified by application, BiDi SFP+ modules, CWDM SFP+ modules, DWDM SFP+ modules, and other common SFP+ optical transceivers are covered. Considering CWDM and DWDM SFP+ transceivers, they are regarded as the most convenient and cost-effective choices for a campus, data-center, and metropolitan-area access networks using 10 Gigabit Ethernet, with a transmission speed up to 11.25G. The CWDM SFP+ transceiver is designed for bi-directional (BIDI) serial optical data communications such as IEEE 802.3ae 10GBASE-LR/LW/ER. It can support 18 wavelengths from 1270 nm to 1610 nm and has steps of 20 nm, with a transmission distance from 20 km to 80 km. The DWDM SFP+ transceiver is specifically designed for carriers and large enterprises that require a scalable, flexible, cost-effective system for multiplexing, transporting and protecting high-speed data, storage, voice and video applications in point-to-point, add/drop, ring, mesh and star network topologies. It supports more than 40 channels with a transmission distance up to 80 km. As for the BiDi SFP+ transceiver, it’s the enhanced small form-factor pluggable fiber transceiver designed for bi-directional 10G serial optical data communications. Working over one fiber, the BiDi SFP+ uses WDM technology sharing transmission directions into wavelengths of 1270 nm and 1330 nm with a distance up to 10 km, 20 km, 40 km, or 60 km.

1490nm 80km CWDM SFP+

Figure 1: 1490nm 80km CWDM SFP+ transceiver connected with single mode LC duplex cable

Classified by wavelength, 10G SFP+ can be grouped into short wavelength SFP+, long wavelength SFP+ and extra long one. For example, SFP-10G-SR belongs to the short wavelength (850 nm), supporting multimode fiber, such as OM3 (300 m) and OM4 (400 m). Besides, the 10G SFP+ copper also belongs to the short one. With an RJ45 connector, it is specifically designed for high-speed communication links that require 10 Gigabit Ethernet over Cat 6a/7 cable with a link limit of 30 m. While SFP-10G-LR can support a long wavelength and a long distance up to 10 km by using a single-mode fiber. For extra long wavelength and extended reach, 10GBASE-ER SFP+ can reach 40 km with the wavelength of 1550 nm by using a single-mode fiber, and also the 10GBASE-ZR SFP+ belongs to the extra long one, which can support the wavelength of 1550 nm with a distance up to 80 km.

10G copper SFP+ transceiver

Figure 2: 10G copper SFP+ and RJ45 Ethernet cable

Conclusion

With the above introduction, we will have a basic idea of what the SFP+ transceiver is and how many types it has. Since the SFP+ transceiver enjoys lots of strengths, such as high density, low cost, and low power consumption, it has been frequently used in the fiber communications industry. Now that the SFP+ possesses a wide range of types, it can meet their different needs. There is no need to doubt the SFP+ transceiver will keep releasing a huge potential in the future.

Who is the Winner of 10G Transceiver?

10G transceiver refers to optical module which can transmit and receive the data signal of 10 gigabits per second. Typically, the fiber optic transceivers including 10G XENPAK, X2, XFP and SFP+ (small form-factor pluggable plus) are widely used for 10 Gigabit Ethernet. But who is the winner among these transceivers? From the following introduction we may find some clues.

XENPAK Transceivers

As the first published form-factor 10G transceiver, the XENPAK, was by far the largest in physical size. This standard was driven primarily by large systems vendors and was intended to support essentially any optical application a system vendor may want to deploy. At the time this multi-source agreement (MSA) was published, 10Gbps optical interfaces supporting transmission distances of 80km or more were of a size and heat dissipation that required a relatively large (by today’s standards) package size.

10g transceiver XENPAK-Transceivers

X2 and XFP Transceivers

Many in the industry recognized the size of the XENPAK as very limiting factor and began working on alternative standards. Over the following two years three alternative MSAs were published, called: X2 and XFP. When these standards were written they were intended to enable optical interfaces supporting up to about 10 km. The X2 and XFP form-factors both saw considerable deployment. As optical technology has advanced over the last ten years, X2 and XFP modules have been developed that support all of the high-power, long-distance applications once reserved to the larger XENPAK transceivers.

X2-and-XFP-transceivers

SFP+ Transceivers

Five years after the first 10Gbps optical transceiver standard was issued, a new MSA was published called the “SFP+”. This agreement has been the basis for the most commercially successful 10Gbps optical transceivers by a large margin.

There are several reasons for the success of the SFP+ standard:

  • Flexibility The SFP+ standard builds on a previous one, the SFP MSA (primarily a 1Gbps standard). SFP+ modules are the same physical size as SFPs and the SFP+ standard allows for either type of module to operate in the new SFP+ slots.
  • Small Size SFP+ modules are one tenth the size of the original XENPAK 10G modules and are the same size as the popular 1Gbps SFP modules. This small size allows the design of systems with 10G ports of the same density as previous generations with 1G ports.
  • Low Cost Since SFP+ modules share many components (bezel, housing, latch/locking mechanism) on the previous SFP standard, the cost of the new 10G modules inherits the low cost of these components. SFP+ units are also lower power, contributing to cost savings

10g transceiver

However, do you really know how to choose the right 10G form-factor? The following aspects should be taken into consideration:

Cost

When considering new or used equipment for a new network build or expansion, attention should definitely be given to the type of 10G ports in that equipment. One important reason is capital costs. Older gear offering XFP, X2 or XENPAK ports may be attractive due to what seems like very low prices. However, the cost of equivalent 10G optics in those older form factors is twice to three times the price of SFP+ based modules. Therefore, when the cost of the optics are included, total system costs may end up higher.

Power

The older XFP, X2 and especially XENPAK gear, both the host system and the 10GBase optical modules, consume considerably more power than the new SFP+ modules. Power costs include capital outlays for larger power/battery plant as well as operational cost of the electrical power itself.

Rack Space

Depending on the location, space in equipment racks can be quite expensive. Equipment utilizing the older 10Gbase interfaces is almost always substantially less dense, consuming more rack space per 10G interface available.

Who is the Winner of 10G Transceiver?

From the above, there is no doubt that SFP+ wins the battle. In consideration of the advantages in cost, size, power and flexibility of supportable optical interfaces, SFP+ is preferred among the 10G transceivers. So far, there has not been any new standard for 10G network due to a higher speed demand of Ethernet. Thus, SFP+ transceivers will remain to dominate the 10G transceiver market.