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The ABCs of Tunable SFP+ & Tunable XFP DWDM Optics

Tunable XFP transceiver and tunable SFP+ transceiver are the hot-swap DWDM Tunable optics used in 10Gbps SONET/SDH, Fibre Channel and Gigabit Ethernet applications. Tunable DWDM transceiver is a unique device which allows customers to set the channel that the laser emits. Generally, the tunable optics is for C-Band 50GHz, starting from channel 16 up to 61 (depends on the manufacturer of the Router/Switch and which channels it supports). This article will shed light on the revolutionary Tunable DWDM transceivers.

Tunable Optics Gives You a lot of Flexibility

The introduction of these new optical components enable telecom, datacom, and enterprises operating a DWDM network to significantly reduce their sparing costs, improve their operational efficiencies, and turn up new customers or circuits in a fraction of the time it would normally take.

  • SFP+ Tunable Transceiver

10G DWDM tunable SFP+ transceiver is compliant to SFP+ MSA. This flexible transceiver can be tuned to any one of C-band channels with 50GHz spacing, supporting data rate of 10 Gbit/s-11.3 Gbit/s. DWDM tunable SFP+ transceiver operates over LC singlemode fiber for a max linking length of 80km.

Tunable SFP+ transceiver

  • XFP Tunable

Tunable XFP can be tuned from channel 1561.83 to 1530.33. This tunable optic has a reach of around 80km depending on the fiber quality and the mux type. The Cisco version is the “ONS-XC-10G-C” and there are more brands like Juniper, Ciena, Extreme and Brocade which are offering these optics.

Tunable Optics in DWDM networks

Typically, a DWDM network is set up with fixed wavelength DWDM transceivers. The laser hardware inside a DWDM optics has a fixed wavelength for transmitting over a DWDM channel. That means if one channel fails, you need this specific channel device in your spare part stock.

10G DWDM Tunable SFP+ & DWDM Tunable XFP+

A DWDM network can be used with 40 channels, so you need to stock 40 fixed wavelength DWDM modules. However, with Tunable SFP+ or XFP modules, you have the possibility to reduce OPEX or be flexible in terms of spare parts and stock.

To build a well-organized DWDM networks, you are supposed to scale up a wavelength planning for ordering the right types. There needs to be a documentation which specific channel is already in use at different locations. By the use of Tunable module, you just need to count the unused DWDM ports instead of each wavelengths and order the needed amount of only this one product. This reduces a lot of complexity and makes the planning so much easier.

Three Tips Before Using Tunable Optics

More expensive Than Fixed Wavelength DWDM Optics

Tunable transceivers renown as spare-optics, provide the flexibility to customers and reduce the amount of spare optics you need r to hold in stock. Owing to the special tunable laser in tunable optics, they are between two and four times more expensive than the regular static DWDM optics.

The following figure shows the cost comparison between DWDM SFP+ and Tunable SFP+ optics from FS.COM and Flexoptics.

DWDM SFP+ Vs Tunable SFP+

Some Switches/Routers Do Not Support CLI Command

In fact, the Tunable XFP/SFP+ can be tuned in different ways. It is such a new technology that currently, most high-end devices make it possible to tune over the command line interface, but not every switch or router is capable of this. For example the ASR9000 and the MX80 can be used for this but the EX4200 series from Juniper does not support this, which is indeed the biggest challenge in the tuning of these optics.

Not the mainstream in Metro & OTN Networks Now

Metro Ethernet network mainly consists of IP nodes, e.g. switches and routers interconnected by numbers of 10G interfaces. Network installers usually implement DWDM connectivity by using colored WDM transceivers in 10G ports and directly connect to dark fiber to line through passive optical multiplexer. According to the above description, only few of the IP node (optical switches and routers) support tuning wavelength of CLI commands.

And as for Optical Transport Networks (OTN), it is focusing on carrying payload and multiplexing, switching and supervising networks in optical Layer 1 domain. But how about tunable optical transceivers in OTN network..? Still, the mainstream is conventional fixed wavelength DWDM transceivers.

This compact device allows end-users to self-select any DWDM channel for each tunable SFP+ transceiver, tune it, and set it as a fixed-channel DWDM optic on demand. The whole DWDM sparing costs can be substantially reduced through the use of Tunable optics. Therefore, it would be popular in the near future.

Conclusion

In fiber optical networks where fixed DWDM channel XFP/SFP+ transceivers are currently used, changing to Tunable XFP/SFP+ transceivers offers the potential for large inventory stock reduction since all wavelengths can now be covered with one transceiver module. Tunable module will make itself a desirable choice to replace the fixed wavelength used in many networks.

10G Ethernet SFP+ Vs. 10G Fibre Channel SFP+

Today’s technology presents unprecedented migration incorporating a wide range of application requirements such as database, transaction processing, data warehousing, integrated audio/video, real-time computing, and collaborative projects. Fibre Channel and Gigabit Ethernet, both are the ideal solutions for IT professionals who need reliable, cost-effective information storage and delivery at fast speeds. Fibre Channel is available in 1G/2G/4G/8G/16G FC and 10GFCoE, 40GFCoE and 100GFCoE nowadays. Gigabit Ethernet is the reigning network for data center and server room. The battle between Fibre Channel and Ethernet is complicated. However, this article will help you solve it out by comparing 10G SFP+ Fibre Channel transceiver modules and 10G Ethernet SFP+ modules.

Encoding Mechanisms of Ethernet and FC

Any time we’re transmitting or storing data, we encode it in some form or another. Then we need to understand the encoding mechanisms of Ethernet and FC.

1, 2, 4, and 8 Gb Fibre Channel all use 8b/10b encoding. Meaning, 8 bits of data gets encoded into 10 bits of transmitted information, the two bits are used for data integrity. For example, Original 1Gb FC is actually 1.0625Gb/s, and each generation has kept this standard and multiplied it. 8Gb FC would be 8×1.0625, or actual bandwidth of 8.5Gb/s. 8.5*.80 = 6.8. 6.8Gb of usable bandwidth on an 8Gb FC link.

10GE (and 10G FC, for that matter) uses 64b/66b encoding. For a 10Gb link using 64b/66b encoding, that leaves 96.96% of the bandwidth for user data, or 9.7Gb/s.

10G SFP+ Fibre Channel Transceiver Module

10G SFP+ Fibre Channel (FC) transceiver, as the name implies, is the 10G optical transceivers used for Fibre Channel applications. 10G FC SFP+ module has the same footprint as SFP form factor and is compliant with MSA SFF-8431. 10G SFP+ Fibre Channel transceivers uses the either the 850nm VCSEL as the transmitter fro multimode fiber or 1310nm/1550nm laser as the transmitters for single-mode fibers in SONET OC-192 /SDH, 10GBASE-SW, 10GBASE-LW, 10GBASE-EW, and 10GBASE-ZW applications.

Cisco DS-SFP-FC10G-LW

Cisco DS-SFP-FC10G-LW, seen in the above image, is the long-range single-mode 10G SFP+ FC optical module for a link length of 10km over 1310nm wavelength. 10GFC is backward compatible with previous generation 8G/4G/2GFC and will auto-negotiate down to the fastest speed supported by both ports. This allows 10GFC devices and switches to be seamlessly integrated into expansion segments of existing FC networks without a forklift upgrade.

10GBASE SFP+ Ethernet Transceiver Module

SFP+ 10G modules is the optical transceiver for serial optical communication applications at 10Gbps. Unlike the SFP+ FC transceivers, 10GBASE SFP+ Ethernet modules can use either copper or fiber cabling. SFP+ 10GBASE-T optical transceiver supports Cat6 RJ45 copper cables for a link length of 30m. 10GBASE SFP+ Ethernet modules are available in several 10 Gigabit Ethernet standards like 10GBASE-SR Ethernet, 10GBASE-LR, 10GBASE-LRM, 10GBASE-ER, 10GBASE-ZR, and 10GBASE-T.

HPE 10G SFP+ module
Cisco SFP-10G-LR is the 10km Cisco 10GBASE-LR SFP+ module that uses 1310nm as the transmitter type over single-mode fiber cables. 10GBASE-LR SFP+ modules cannot be auto-negotiate with 1000BASE SFP transceivers, but for most switches, SFP+ ports can support 1G SFP modules for 1Gbps data rate.

Comparison Between 10G Fibre Channel SFP+ and 10G Ethernet SFP+

From the previous description, we can easily draw a conclusion that 10G Fiber Channel SFP+ and 10G Ethernet SFP+ share several specification in common.

  • Footprint

They have the same form factor as 1000BASE SFP transceiver modules.

  • Performance

Except the application, 10G Fiber Channel SFP+ SW module and 10Gb SR SFP+ transceivers have the very similar functions with each other. For the exact information, please see the following table.

10G SFP+ FC modules

  • Application

10G Fiber Channel SFP+ is used in 10G Fibre Channel, yet 10G Ethernet SFP+ is utilized in 10G Ethernet networks.

2017 Prediction of Ethernet and Fibre Channel

Without denying, Ethernet is the dominating network for every data center and server room. The “old” Ethernet network—1Gb/s and 10Gb/s speeds relied heavily on TCP to deliver data, which was reliable but somewhat unpredictable. However, today’s Ethernet runs at 25, 40, 50, or 100Gb/s speeds, is no longer dependent on TCP alone. It also supports RDMA connections which lower latency and frees up CPU cycles to run applications. 100Gb/s technology is quite matured in 2017 and there are many relevant devices available on the market, such as CFP/QSFP28 optical transceivers, 100G switches and network interface cards, 24 fiber MTP cables, etc.

Fibre Channel Vs. Gigabit Ethernet

Meanwhile, FC is still transitioning to 16/32 Gb/s technology (32Gb/s is not mature), which is quite slower than what Ethernet was supporting several years ago. For 32Gb/s FC network, it still supports only block storage traffic. Other storage (and other non-storage) traffic will require an Ethernet network anyway.

If we look at what is coming in 2017, the battle will not be 10/40/100GbE Vs. 8/10/16/32Gb FC. Almost everyone would agree that it would be nice to have a single network for all traffic, and very few users want a new protocol and the challenges of changing the way that they do things.

Conclusion

FC or Ethernet, which is best for storage? 10Gb FC SFP+ has the same usable bandwidth as the 10Gb Ethernet SFP+, and without the overhead of FCoE, but you don’t get the consolidation benefits of using the same physical link for your storage and traditional Ethernet traffic. FS.COM offers reliable 10G SFP+ transceivers in Ethernet, FC, BiDi, CWDM/DWDM applications. If you are interested in our products, please contact us directly.

How to Choose Fiber Optic Cable for 10G SFP+ Optical Transceiver?

How to choose fiber optic cables for 10G SFP+ transceivers? It seems like a dumb question for most of the fiber optic technicians. However, there are still some people, especially the green-hand network installers, may not know the compatibility between fiber optic cables and optical transceiver modules. Today, I want to make a clear illustration of how to choose the right transmission media (OS2/OM3/OM4/Cat6/Cat6a) for 10G SFP+ optical transceiver modules.

Overview of SFP+ Optical Transceiver Module

Before coming to the main part of this article, let’s first have a brief overview of the SFP+ optical transceiver modules and 10G fiber & copper cables.

  • 10GBASE SFP+ optical transceivers

SFP+ optical transceivers, according to the IEEE standards, can be divided into several types, for example, 10GBASE-LRM SFP+, 10GBASE-LR, 10GBASE-ER SFP+, 10GBASE-ZR SFP+, 10GBASE-SR SFP+, 10GBASE-T SFP+. Each SFP+ optical transceiver type has its own specification and usage that are not be listed here. For more, please review the previous articles.

  • BiDi SFP+ Modules

Besides the above 10GBASE SFP+ modules, 10GBASE-CWDM SFP+, 10GBASE-DWDM SFP+ and SFP+ BiDi optical transceiver modules are also the most commonly used 10G SFP+ optics. SFP+ BiDi optical transceiver usually uses two different wavelength to achieve 10G transmission over one fiber. The most frequently used wavelength of BiDi optical module is 1310nm/1550nm, 1310nm/1490nm, 1510nm/1590nm.

bidi-10G-SFP+--transceiver-simplex-cable

  • CWDM/DWDM SFP+ Modules

The Coarse Wavelength-Division Multiplexing (CWDM) and Dense Wavelength-Division Multiplexing (DWDM) SFP+ optics are the convenient and cost-effective solution for the adoption of 10 Gigabit Ethernet in campus, data-center, and metropolitan-area access networks. This 10G fiber optic transceiver type can support up to eight channels of 10GbE over single-mode fibers for distance over 80km.

10G Fiber & Copper Patch Cables

Fiber optic cables can be categorized into two types: single-mode and multimode fiber optic cables. They have different core size and fiber optic transmission equipment, which makes them suitable in different applications. Single-mode fiber patch cables, or OS1/OS2 (OS1 is now not popular on the market) are normally used for long-distance transmission with laser diode based equipment.

OS2 OM4 Cat6a for 10G SFP+ module

Multimode fiber cables, or OM1/OM2/OM3/OM4, have a relatively large light carrying core, usually utilized for short-distance transmission with LED based equipment. OM1, with a core size of 62.5um, supports 1GB network within 300m. OM2 (50um) can support up to 10GB, with a distance of 600m. OM3 and OM4 are the laser-optimized multimode fibers, which can be used in 10GB network with a link length of 300m, 550m respectively. These types of optical cables can be also used on 40G/100G network utilizing a MTP/MPO connector.

Cat6/Cat6a cables are the Copper Ethernet Network cables used for 10G network. Compared with Cat5e (1 Gigabits of data) and Cat5 cables (10/100 Mbps), Cat6 is the Ethernet cable that can handle up to 10Gbps with the distance limited to 164ft. Cat6a is the advanced version of Cat6 cables that further reduce crosstalk, which makes it can support the full 328 feet of Ethernet cable.

Choosing Fiber Optic Cables for 10G SFP+ Optical Transceivers

As noted before, single-mode patch cables can be used for 10G 10GBASE-LRM SFP+, 10GBASE-LR SFP+, 10GBASE-ER SFP+, 10GBASE-ZR SFP+, 10GBASE-CWDM SFP+, 10GBASE-DWDM SFP+ and SFP+ BiDi modules.

Cable Type Connector Max Distance
10GBASE-LRM SFP+ 9/125 SMF LC Duplex 200m
10GBASE-LR SFP+ 9/125 SMF LC Duplex 10km
10GBASE-ER SFP+ 9/125 SMF LC Duplex 40km
10GBASE-ZR SFP+ 9/125 SMF LC Duplex 80km
CWDM SFP+ 9/125 SMF LC Duplex 80km
DWDM SFP+ 9/125 SMF LC Duplex 80km
SFP+ BiDi 9/125 SMF LC/SC Simplex 80km

Multimode fibers, especially the OM3 and OM4 cables, are supported for 10GBASE-SR SFP+ transceiver modules. The following chart displays the part No. of customized OM3 and OM4 cables.

Customized Part ID
Connector
Fiber Mode
Polish Types
Jacket
Stock Length
17235 LC Duplex 50/125 OM4 UPC PVC 1m-30m (3ft-98ft)
17235 LC Duplex 50/125 OM4 UPC LSZH 1m-15m (3ft-49ft)
17235 LC Duplex 50/125 OM4 UPC OFNP 1m-15m (3ft-49ft)
12018 LC Duplex 50/125 OM3 UPC PVC 1m-30m (3ft-98ft)
12018 LC Duplex 50/125 OM3 UPC LZSH 1m-30m (3ft-98ft)
12018 LC Duplex 50/125 OM3 UPC OFNP 1m-15m (3ft-49ft)

Cat6 and Cat6a Patch cables can be only used on the 10GBASE-T SFP+ transceivers.

10GBASE-T RJ45 SFP+ Copper module

Keep in mind, the newly available SFP+ copper transceiver modules can only support up to 30m.

Conclusion

This article lists all the existing the 10G fiber & copper patch cables and SFP+ transceiver module types, as well as the guidance about how to select the right patch cables for 10G SFP+ optical transceivers. FS.COM offers a full range of SFP+ optical transceiver modules and patch cables. Please contact us if you need any help.

Original article: 10GBASE-T SFP+ COPPER RJ45 TRANSCEIVER MODULE – INNOVATIVE BUT CONTROVERSIAL