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Which Tight Buffered Fiber Distribution Cable Fits Your Application?

Optical fibers with fiber counts ranging from 2 to 144 counts or more are usually coated together inside a single strand of fiber optic cable for better protection and cabling. Multi-fiber optic cables are usually required to pass a lot of distribution points. And each individual optical fiber should connect only one specific optical interface via splicing or terminating by connectors. Thus, fiber optic cables used for distribution should be durable and easy to be terminated. Tight buffered fiber distribution cables, which meet these demands, are widely used in today’s indoor and outdoor applications, like data center and FTTH projects. This post will introduce tight buffered fiber distribution cables.

tight buffered fiber cable

The Beauty of 900um Tight Buffered Fibers

Most of tight buffered fiber distribution cables are designed with 900um tight buffered fibers. This is decided by its applications. As the above mentioned, the distribution cable should be durable and easy to be terminated. The following picture shows the difference between 250um bare fiber and 900um tight buffered fiber. They are alike, but the tight buffered fiber has an additional buffer layer. Compared with bare fibers, 900um tight buffered fibers can provide better protection for the fiber cores. 900um tight buffered fibers are easy to be stripped for splicing and termination. In addition, tight buffered fiber cables are usually small in package and flexible during cabling. These are the main reasons why a lot of fiber optic distribution cables use tight buffered design.

250um vs 950um

Choose Tight Buffered Distribution Fiber Cables According to Applications

900nm tight buffered distribution fiber cables also come in a variety of types. Tight buffered distribution fiber cables used for different environments and applications might have different fiber types, outer jackets and cable structures. The following will introduce several tight buffered distribution fiber cables for your reference.

unitized distribution fiber cable
Indoor Tight Buffered Distribution Fiber Cable

Tight buffered distribution fiber cables used for indoor applications are usually used for intra building backbones and routing between telecommunication rooms. Large tight buffered fiber cable with fiber counts more than 36 fibers generally has “sub-unit” (unitized) design (shown in the above). While smaller tight buffered distribution cables, with fiber counts of 6, 12 or 24, usually have “single-jacket” (non-unitized) designs, which are more flexible in cabling and have much smaller packages and cost advantages. The lower count tight buffered distribution fiber cables with color coded 12 fibers and 24 fibers are very popular. The following picture shows a 24-fiber indoor tight buffered distribution fiber cable with single-jacket design.

24-fiber tight buffered fiber cable

During practical use, these 6, 12 or 24-fiber indoor tight buffered distribution fiber cables can be spliced with other fibers or be terminated with fiber optic connectors. And they can be made into multi-fiber optic pigtails or fiber patch cable after terminated with fiber optic connector on one end or two end. The color coded fibers can also ease fiber cabling.

Indoor/Outdoor Armored Tight Buffered Distribution Fiber Cable

Although tight buffered distribution fiber cables are usually used for indoor applications, there is still a place for them in outdoor applications after added with a layer of metal armored tube inside the cable. Armored fiber cables are durable, rodent-proof, water proof and can be directly buried underground during installation, which saves a lot of time and money.

Armored tight buffered distribution fiber cable

Here we strongly recommend a low fiber count armored tight buffered distribution fiber cable which can be used for both indoor and outdoor applications (show in the above picture). This low fiber count armored tight buffered cable has a single-jacket design with a steel armored tape inside the cable. It can be used for both backbone cabling and horizontal cabling in indoor environments. And it can also be used for direct buried applications and aerial application in outdoor environments.

FS.COM Same Day Shipping Tight Buffered Distribution Fiber Cables Solution

During the purchasing of fiber optic cables, one of the most important thing is the shipment of fiber cables. Many bulk fiber cables are transmitted via shipping, which might take a long time. Now FS.COM customers in the USA can enjoy same day shipping for tight buffered distribution fiber cables for both indoor and outdoor applications. Details are shown in the following table. Kindly contact sales@fs.com for more details, if you are interested.

Part No.	Description
31909	12 Fibers OM3 Plenum, FRP Strength Member, Non-unitized, Tight-Buffered Distribution Indoor Fiber Optical Cable GJPFJV
31922	12 Fibers OM4 Plenum, FRP Strength Member, Non-unitized, Tight-Buffered Distribution Indoor Fiber Optical Cable GJPFJV
31866	24 Fibers OM4 Riser, FRP Strength Member, Non-unitized, Tight-Buffered Distribution Indoor Fiber Optical Cable GJPFJV
51308	24 Fibers OS2, LSZH, Single-Armored Double-Jacket, Tight-Buffered Distribution Waterproof Indoor/Outdoor Cable GJFZY53

100G QSFP28 Fiber Optic Modules and Standards

The developing of 100G fiber optic transceiver has experienced a lot of challenges, thus various types of 100G fiber optic transceivers are being invented. Many 100G modules appeared on the market for a while and disappeared soon. Now it seems that 100G QSFP28 module will win the competition. It has the same cabling structure as 40G QSFP+ module and high density feature, which allows network upgrade to 100G with lower cost and less time. This post will introduce several commonly used 100G QSFP28 modules and standards.

100G QSFP28

QSFP28 module uses four lanes for 100G optical signal transmitting like 40G QSFP+. However, each lane of QSFP28 can transmit 25G optical signal. To fit the various requirements in practical applications, IEEE and MSA standards that support different transmission distances and fiber types are being published.

100G QSFP28 SR4

100G QSFP28 SR4 is a standard published by IEEE. 100G QSFP28 SR4 module uses eight multimode fibers for 100G dual-way transmission over 850nm. It can support a transmission distance up to 70m over OM3 and 100m OM4 with a MTP interface. 12-fiber MTP OM3/OM4 trunk cables are suggested to be used with QSFP-100G-SR4 modules. 100Gbase-SR4 QSFP28 is the most popular QSFP28 module according to research.

100G QSFP28 LR4

100G QSFp28 LR4 is another 100G standards published by IEEE. It focuses on longer transmission distance over single-mode fiber. 100G QSFP28 LR4 has a duplex LC interface and uses WDM technologies to achieve 100G dual-way transmission over four different wavelengths around 1310nm. It can support distances up to 10km.

Although IEEE has defined two 100G standards separately for short and long distances, the requirements of various applications cannot be fully satisfied. For instances, the 100G-QSFP-LR4 module can support 10km, which is too much for a lot of single-mode applications. It would be uneconomical to buy a 10km module for just 1km or 2km application. MSA has published two 100G standards — 100Gbase-PSM4 and 100Gbase-CWDM4, which can help to decrease the cost of 100G deployment.

100G QSFP28 PSM4

100G QSFP28 PSM4 module has a MTP interface working on wavelength of 1310nm for 100G transmission over single-mode fibers. It can support transmission distance up to 500 meters. 100G QSFP28 PSM4 module is much cheaper than 100Gbase-LR4 QSFP28 module. And 500 meter’s transmission distance can cover a wide range of applications.

100G QSFP28 CWDM4

For longer transmission distance, 100G QSFP28 CWDM4 is suggested, which supports a distance up to 2km over single-mode fiber optic cable. 100Gbase-CWDM4 standard is published by MSA, which is a more cost-effective solution for a wide range of applications compared with 100Gbase-LR4. This module uses CWDM technologies to transmit the 100G optical signal via a duplex LC interface over wavelengths near 1310nm.

100G QSFP28 DAC

100G QSFP28 family also includes a series of direct attach cables. There are mainly two types of QSFP28 DAC, which are QSFP28 to QSFP28 DAC and QSFP28 to SFP28 DAC. These QSFP28 DACs are cost-effective solution for 100G transmission less than 5 meters.

100G QSFP28 Module	Interface	Fiber Type	Distance	Standards
100Gbase-SR4 QSFP28	MTP	Multimode	70m (OM3); 100m (OM4)	IEEE
100Gbase-LR4 QSFP28	LC Duplex	Single-mode	10km	IEEE
100Gbase-PSM4 QSFP28	MTP	Single-mode	500km	MSA
100Gbase-CWDM4 QSFP28	LC Duplex	Single-mode	2km	MSA

Conclusion

There are many ways to transmit to 100G network. 100G QSFP28 modules are the suggested methods. Both IEEE and MSA published standards for 100G QSFP28. For short distance transmission over multimode, 100Gbase-SR4 QSFP28 module is suggested. For single-mode applications, 100Gbase-PSM4 supporting 500m, 100Gbase-CWDM4 supporting 2km and 100Gbase-LR4 supporting 10km are available. The above table shows the basic information of these modules for your reference.

Difference Between 100G-QSFP-PSM4, 100G-QSFP-SR4 and 100G-QSFP-LR4

QSFP28 fiber optic transceiver is becoming the preferred solution for 100G network. It has the same outside looking as the 40G QSFP+ transceiver. But it has a 4*25G electrical interfaces which can transmit optical signals up to 100G. The part numbers of the QSFP28 transceivers are usually market as 100G-QSFP-xx. Now there is a wide selection of 100G QSFP28 modules for 100G Ethernet link, including fiber optic transceiver and direct attached cable. Different part numbers of 100G modules are making customers confused. This post will introduce the differences between the three 100G QSFP28 modules: 100G-QSFP-PSM4, 100G-QSFP-SR4 and 100G-QSFP-LR4.

100G QSFP

Transmission Mode

It is known that QSFP28 modules generally use four lanes to transmit 100G with each lane supporting 25G. Thus, the transmission method is just like 40G QSFP+ transceiver. 100G QSFP28 SR4, LR4 and PSM4 all use the 4*25 transmission mode. However, both the QSFP28 SR4 and QSFP28 PSM4 use a 12-fiber MTP interface which achieves dual-way 100G transmission over 8 fibers at the same time. QSFP28 LR4 uses a LC duplex fiber optic interface for 100G transmission on two directions at the same time. QSFP28 LR4 transmit optical signals over four different wavelengths around 1310nm with each wavelength carrying 25G optical signal. The wavelength ranges of the four lanes are as following:

1294.53nm-1296.59nm
1299.02nm-1301.09nm
1303.54nm-1305.63nm
1308.09nm-1310.19nm

Transmission Media and Distances

The three modules can support different transmission distances. 100G-SR4 QSFP28 module works over wavelength of 850nm and is used with 12-fiber MTP OM3 or OM4 multimode fiber cables for short transmission distances up to 100m. 100G-LR4 QSFP28 module is suggested to be used with single-mode fiber. It works over 1310nm wavelengths and can transmit 100G signals up to 2km. 100G-PSM4 QSFP28 is also used with 12-fiber MTP fiber cables but the fiber type is single-mode and the transmission distance is up to 500m.

100G-QSFP-SR4

Cabling Structure

The transmission mode of the fiber optic transceiver plays an important role during fiber cabling. 100G-QSFP-SR4 and 100G-QSFP-LR4 are invented for short distance transmission and long distance transmission separately. However, the have different cabling structure. The former requires a multi-fiber cabling structure based on 12-fiber MMF MTP interfaces. While 100G-QSFP-LR4 just required the traditional two-fiber SMF cabling structure. In this case, the conversion between multimode fiber to single-mode fiber would be complex as they used totally different cabling structure. Thus, 100G-QSFP-PSM4 is invented which runs over single-mode fiber, but uses the same cabling structure as 100G-QSFP-SR4. With 100G-QSFP-PSM4, the conversion between multimode and single-mode would save more without changing the existing fiber cabling structure.

100G QSFP28 Transceiver	Data Rate	Interface	Fiber Type	Transmission Distance	Wavelengths	Cabling Structure
100G-QSFP-SR4	4*25G	MTP	MMF	70m (OM3); 100m (OM4)	850nm	12-Fiber MTP
100G-QSFP-LR4	4*25G	LC	SMF	2km	1310nm	LC Duplex
100G-QSFP-PSM4	4*25G	MTP	SMF	500m	1310nm	12-Fiber MTP

Conclusion

The above table listed the basic information of the three modules for your referent. 100G-QSFP-SR4 are suitable for short distance transmission over OM3 or OM4 fiber using 12-MTP fiber cabling system. 100G-QSFP-PSM4 also has a 12-fiber MTP interface but it can support a transmission distance up to 500m over SMF. 100G-QSFP-LR4 is suitable for long transmission distance up to 2km over two single-mode fibers.

Related Article: 40G vs 100G: Which One Is Worth the Investment?

Cisco S-Class vs Non-S-Class Module

Cisco switches and fiber optic transceivers are considered as the benchmarks of the market with a market share more than 50%. With the development of fiber optic network, Cisco has developed a variety of fiber optic transceivers for different applications and has built a system to name each transceiver. For instance, the most commonly used 10G Cisco modules like SFP-10G-SR and SFP-10G-LR have part numbers which can accurately descript their biggest features. SR means “short range” and LR means “long range”. However, customers find the part numbers of some Cisco modules are named with an “S”, like SFP-10G-SR-S and SFP-10G-LR-S. Cisco calls them S-class modules. People might get confused by these Cisco S-class modules. Cisco S-Class vs Non-S-Class module, or SFP 10G SR S vs SFP 10G SR, which one should you choose?

sfp 10g sr s vs sfp 10g sr

Cisco S-Class Module VS Cisco Non-S-Class Module

Cisco only published four 10G S-class SFP+ modules and two 40G S-class QSFP+ modules. The following table listed Cisco S-class modules. Cisco S-class modules seem to have no differences from the non-S-class modules. However, if you read the specification of these modules and the suggestions from Cisco, you will find the differences.

Data Rate	S-Class Module	Non-S-Class Module	Media
10G	SFP-10G-SR-S	SFP-10G-SR	MMF (duplex)
10G	SFP-10G-LR-S	SFP-10G-LR	SMF (duplex)
10G	SFP-10G-ER-S	SFP-10G-ER	SMF (duplex)
10G	SFP-10G-ZR-S	SFP-10G-ZR	SMF (duplex)
40G	QSFP-40G-SR4-S	QSFP-40G-SR4	MMF (ribbon)
40G	QSFP-40G-LR4-S	QSFP-40G-LR4	SMF (duplex)

Protocol

The standard non-S-class Cisco modules like SFP-10G-SR and SFP-10G-LR can support three protocols including Ethernet, OTN (Optical Transport Network) and WAN-PHY (Wide Area Network Physics). However, the S-class modules can only support Ethernet protocol.

Temperature Range

Compared with Cisco C-class modules which can be operating with three different temperature ranges, the Cisco S-class modules can only support the commercial temperature ranges which is 0 to 70°C (32 to 158°F).

Commercial temperature range (COM): 0 to 70°C (32 to 158°F)
Extended temperature range (EXT): -5 to 85°C (23 to 185°F)
Industrial temperature range (IND): -40 to 85°C (-40 to 185°F)

Transmission Distance

Cisco has introduced that the S-class modules are suggested to be used in enterprise network. In addition, the operating temperature range is smaller, thus, S-class module is recommended for shorter transmission distance applications compared with other standard modules.

Price

As the performance of Cisco S-class modules are no better than other modules, why did Cisco published these modules? This is because Cisco S-class modules have lower prices, which is also their biggest sale point.

cisco s-class module

Should I Choose Cisco S-Class Module?

In conclusion, S-class can only support Ethernet protocol and has a commercial temperature range, which is suggested to be used in applications that no special long distance, temperature tolerances, or other special features are required. But many people might not select S-class modules, considering about the future use. As Cisco original branded transceivers are expensive, many people will use third party modules which are much cheaper but is compatible with Cisco devices. A Cisco compatible non-S-class module could be much cheaper than a Cisco original brand S-module. But it can provide almost the same performance as the Cisco original branded non-S-class module.

Related Article: Cisco SFP-10G-SR: All You Need to Know

A Comprehensively Understanding of Cisco 10GBASE SFP+ Modules

How to Select 10G SFP+ Modules for Cisco Switches?

10G fiber optic network is being widespread in today’s telecommunication network. A lot of 10G fiber optic devices like switches are being uses, among which Cisco devices are the most commonly used according to statistics. If you choose a Cisco switch, Cisco original brand or Cisco compatible modules like SFP/SFP+ might be needed for transferring between optical signals and electrical signals. This post will offer details about how to select the proper 10G SFP+ module for Cisco switches.

Understand 10G IEEE Standards and How Cisco Name Its Modules

10G fiber optic network is mature now, and there is a wide selection of 10G IEEE standards for different 10G networking applications and environments. Before you buy 10G SFP+ modules for your Cisco switches, you should firstly get to know these 10G standards.

10G IEEE Standards

IEEE has defined 10G standards for different transmission distance and transmission media. For instance, there are 10GBASE-SR SFP+ for short distance up to 300 meters over OM3 multimode optical fiber and 10GBASE-LR for long distance up to 10 kilometers over single-mode fiber. There are also standards for 10G transmission over copper cables like 10GBASE-CR and 10GBASE-T. The following table listed the details for the most commonly used 10G standards.

10G IEEE Standards	Description
10GBASE-SR	Support 10G transmission over wavelength of 850nm via multimode fiber in short distances: OM3 (up to 300m) and OM4 (up to 400m).
10GBASE-LR	Support 10G transmission over single-mode fiber up to 10km over wavelength of 1310nm.
10GBASE-LRM	Support 10G transmission over standard multimode fiber up to 200m over wavelength of 1310nm.
10GBASE-ER	Operate over 1550nm wavelength and support transmission distance up to 40km over single-mode fiber. Attenuation is required for transmission distance shorter than 20km.
10GBASE-ZR	Support 10G transmission over 1550nm single-mode fiber optic up to 80km. For short links, attenuation is required to ensure transmission quality.
10GBASE-BX	Support duplex 10G transmission over a single single-mode fiber using two different wavelengths up to 80km.
10G CWDM/DWDM	Support 10G transmission over 1550nm single-mode fiber optic up to 80km. For short links, attenuation is required to ensure transmission quality.
10GBASE-CR	Support 10G transmission over Twinax copper cable in very short distance and offer a cost-effective way for connections within racks.

Product Name of Cisco 10G SFP+ Modules

The naming system of Cisco 10G SFP+ modules is closely related to the IEEE standards. Here I listed several examples for Cisco SFP+ module to better illustrate how Cisco names its 10G SFP+ modules.

10G IEEE Standards	Cisco 10G Modules Product Number Example
10GBASE-SR	Cisco SFP-10G-SR
10GBASE-LR	Cisco SFP-10G-LR
10GBASE-LRM	Cisco SFP-10G-LRM
10GBASE-ER	Cisco SFP-10G-ER
10GBASE-ZR	Cisco SFP-10G-ZR
10GBASE-BX	Cisco SFP-10G-BXD-I & SFP-10G-BXU-I; Cisco SFP-10G-BX40D-I & SFP-10G-BX40U-I
10G CWDM/DWDM	Cisco CWDM-SFP10G-1470; Cisco DWDM-SFP10G-61.41
10GBASE-CR	Cisco SFP-H10GB-CU1M; Cisco SFP-H10GB-ACU7M

For common 10G SFP+ modules, Cisco uses the key words of the standards to name the responding modules. For special modules, Cisco has built another naming system.

SFP+ module

For a pair of BiDi SFP+ modules, letter “D” and “U” is used to the two modules that are used together on each end of the fiber optic link. For instance, SFP-10G-BXD-I & SFP-10G-BXU-I is a pair of BiDi Modules that can support transmission distance up to 10km. Additional numbers are added to mark the transmission distance of the BiDi modules. SFP-10G-BX40D-I & SFP-10G-BX40U-I is a pair of BiDi SFP+ modules that can support transmission distance up to 40km.

For CWDM 10G SFP+ and DWDM SFP+, the wavelength is added in the part number. For instance, CWDM-SFP10G-1470 is the part number of a CWDM SFP+ that is operated at wavelength of 1470nm. If you want a CWDM SFP+ operating over 1550nm, then the product number of this CWDM module should be CWDM-SFP10G-1550. As all the DWDM SFP+ modules are operated over wavelengths around 1500nm, in the product number of Cisco DWDM SFP+ modules, the first two number 1 and 5 is eliminated. For example, DWDM-SFP10G-61.41 stands for a DWDM SFP+ transceiver with operating wavelength of 1561.41nm.

10G SFP+ DAC

For modules like SFP+ direct attach cable (SFP+ DAC) and SFP+ active optical cable (SFP+ AOC) which contains a length of cables, Cisco combines the characters of IEEE standard and number to name its modules. Cisco SFP-H10GB-CU1M stands for 10G SFP+ direct attach copper cable that is one-meter long. Cisco SFP-10G-AOC2M is a 2-meter long 10G SFP+ active optical cable.

Do You Really Need Cisco Original Brand SFP+ Module?

Except IEEE standard and transmission distance, to select the proper 10G SFP+ module should also considerate several other factors like compatibility and costs.

Although Cisco has a wide selection of switches and 10G SFP+ modules, but not every SFP+ modules can work well on every Cisco switches SFP+ port. Before selecting the SFP+ msodule for your Cisco switch, you must make sure this SFP+ is compatible with your switch.

The second important factor is the costs for the SFP+ modules. Why? SFP+ module is just a small part of the whole fiber optic network, but the use amount of SFP+ module is very large. Cisco Original brand SFP+ modules are usually expensive. Thus, select cost-effective modules are necessary. Actually, Cisco Original brand SFP+ module is not the only choice. There are also many third party modules that it compatible with Cisco switches. Generally, prices of third party fiber optic transceivers are much lower than the original brand ones.

How to Buy Cisco 10G SFP+ Module?

If you have plenty of money, you can directly order the modules from Cisco. However, if you are going to select the third party modules for a cost-effective solution, then the quality and compatibility would be very important. FS.COM is a provider offers a full range of Cisco compatible modules. All its modules are fully tested in original brand switches to ensure the compatibility and quality. What’s more, FS.COM uses the same naming system as Cisco for its Cisco compatible modules and generic fiber optic modules. A list is also offered in the product page of each fiber optic modules showing the compatible switches and platforms. Customer can use the Cisco product number to search Cisco Compatible and generic modules in FS.COM directly.

Related Article:

Cisco SFP-10G-SR: All You Need to Know