Consider Two Things Before Deploying 10 Gigabit Ethernet

Over the years, Ethernet technologies have evolved rapidly and amazingly to meet the never-ceasing requirements of higher bandwidth and faster data transmission speeds for high quality network applications, such as live video and video download with high resolution. Through this great evolution, Ethernet technology standards have been designed, like 10 Gigabit Ethernet (GbE).

After IEEE Standard 802.3ae- 2002 for 10GbE was ratified several years ago, some enterprises have begun to deploy 10GbE in their data centers to support bandwidth-needing applications. Before deploying 10GbE, as matter of fact, there are many things that should attract your attention. Here this article lists two important things you need to consider for a reliable 10GbE deployment: 10GbE cabling choices, and 10GbE transceiver types.

10GbE Cabling Choices

Along with the technological revolution, cables used for transmission also experienced progressive development. There are two physical media available for 10GbE transmission: fiber and copper.

10GbE Fiber Cabling Choices

Fiber cables fall on two classifications: single-mode fiber (SMF) and multi-mode fiber (MMF). In SMF, there is only one path for light, while in MMF light flow through multiple paths. SMF is intended for long distance communication and MMF is used for distances of less than 300 m. Commonly used 10GbE ports designed for SMF are 10GBASE-LR, 10GBASE-ER and 10GBASE-ZR, and the ports specified for MMF are 10GBASE-SR and 10GBASE-LRM. It’s of great importance to choose these ports 10GbE transmission when link lengths matter. For example, you can choose a J9150A transceiver when the required distance is less than 300m. In a word, the form factor options depend on your link lengths.

10GbE Copper Cabling Choices

As the structured cabling techniques become mature, copper cabling technology also grasps the chance to develop itself. And more and more people start to choose copper cables as the medium for 10GbE transmission. 10GBASE-T and SFP+ direct attach cables (DAC) standards symbolize copper applications.

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, over distances up to 100 metres (330 ft). It requires the Cat 7 or Cat 6A to reach 100 meters, but can still work on Cat 6, Cat 5E, or even Cat 5 cable when reduced distances are required.

SFP+ DAC is the latest standard for optical transceivers, and it connects directly into an SFP+ housing. In SFP+ DAC cabling assembly, no optical transceiver is used at each end. A cable was invented with each end physically resembling a SFP+ transceiver, but with none of the expensive electronic components. This creation is known as DAC. Actually, besides 10GbE applications, DAC is also considered as a cost-effective solution to replace fiber patch cables sometimes in 40GbE systems. Like QSFP-H40G-ACU10M, this Cisco 40G cabling product is the QSFP to QSFP direct attach passive copper cable assembly designed for 40G links.

QSFP-H40G-ACU10M ,QSFP to QSFP direct attach passive copper cable assembly

10GbE Transceiver Types

After choosing cables, you need to select devices that connect these cables to your networks. These devices are transceivers. 10GbE has four transceiver types: XENPAK (and related X2 and XPAK), GBIC, SFP and SFP+.

XENPAK is a Multisource Agreement (MSA) that defines a fiber-optic or wired transceiver module which conforms to the 10 Gigabit Ethernet (10GbE) standard of the Institute of Electrical and Electronics Engineers (IEEE) 802.3 working group.

X2 defines a smaller form-factor 10 Gb/s pluggable fiber optic transceiver optimized for 802.3ae Ethernet,ANSI/ITUT OC192/STM- 64 SONET/SDH interfaces,ITUT G.709,OIF OC192 VSR,INCITS/ANSI 10GFC (10 Gigabit Fibre Channel) and other 10 Gigabit applications.X2 is initially centered on optical links to 10 kilometers and is ideally suited for Ethernet,Fibre Channel and telecom switches and standard PCI (peripheral component interconnect) based server and storage connections. X2 is physically smaller than XENPAK but maintains the mature electrical I/O specification based on the XENPAK MSA and continues to provide robust thermal performance and electromagnetic shielding. The 10GB X2 fiber optic transceivers series include X2-10GB-SR, X2-10GB-LR, X2-10GB-ER and X2-10GB-ZR, they are designed based on the X2 MSA and IEEE802.3ae. They’re created for the integrated systems solution provide, fiber optics distributor along with other IT distributors.

SFP+, also called SFP Plus, is short for enhanced small form-factor pluggable, an enhanced version of the SFP that supports data rates up to 16Gbit/s. SFP+ 10GbE transceiver series include SFP+ 10GBASE-SR, SFP+ 10GBASE-LR, SFP+ 10GBASE-ER, and so on. Among these types, 10GBASE-SR is widely used when the required distance is less than 500m. Say SFP-10G-SR, this Cisco 10GBASE-SR SFP+ transceiver listed in Fiberstore is designed to support 10GbE applications with the maximum distance reach of 300m.

Conclusioni

After discussion, maybe you have obtained a better understanding of 10GbE cables and transceivers, which helps you to better choose the right devices for your 10GbE applications. Fiberstore supplies various numbers of 10GbE cables and transceivers which are quality assured. For more information about 10GbE solutions, you can visit Fiberstore directly.

The Evolution of 10GbE Cabling Technologies

Since Ethernet technology is born in 1970s, it has evolved continuously to meet the never-ceasing demands of even faster rates of data transmission, such as 10 Gigabit Ethernet (GbE). Along with this ongoing evolution, the cabling technologies that support the 10GbE applications have also advanced, so as to provide greater bandwidth to transmit data with reasonable cost and decreased complexity. Maybe you have few insights in this evolution. Don’t worry. This text mainly talks about the evolution of 10GbE cabling technologies, including fiber and copper cabling technologies.

The Institute of Electrical and Electronics Engineers (IEEE) 802.3 working group has published several standards regarding 10GbE, including 802.3ae-2002 (fiber -SR, -LR, -ER), 802.3ak-2004 (CX4 copper twin-ax InfiniBand type cable), etc. Actually, the evolution of cabling technologies have walked in step with that of 10GbE standards, especially associated with the difference between IEEE802.3ae and IEEE802.3ak standards.

IEEE802.3ae

Ratified in June 2002, the IEEE802.3ae standard outlined the following port types.

10GBASE-SR—It supports 10GbE transmission over standard multi-mode fiber (MMF) with distances of 33m on OM1 and 86m on OM2. Using 2000 MHz/km MMF (OM3), up to 300-m link lengths are possible. Using 4700 MHz/km MMF (OM4), up to 400 meter link lengths are possible. Like SFP-10G-SR-S (shown below), this Cisco 10GBASE-SR module listed in Fiberstore is able to support up to 300m using OM3 at the maximum data rate of 10.3125Gbps. In addition, SR is the lowest-cost optics (850nm) of all defined 10GbE optics.

SFP-10G-SR-S, supporting 300m link length using OM3

10GBASE-LR—This port type uses higher cost optics (1310nm) than SR and requires more complex alignment of the optics to support 10km link length over single-mode fiber (SMF).

10GBASE-ER—It’s a port type for SMF and uses the most expensive optics (1550nm) lasers, enabling a reach of 40km over engineered links and 30km over standard links.

IEEE802.3ak

Approved in February 2004, this IEEE802.3ak standard only defined 10GBASE-CX4—the first 10GbE copper cabling standard.

10GBASE-CX4—It’s a low-cost 10GbE solution intended for copper cabling with short-distance connectivity. Its affordability and wide availability makes 10GBASE-CX4 ideal for wiring closet and data center connectivity.

The CX4 standard transmits 10GbE over four channels using twin-axial cables which originated from Infiniband connectors and cable. The CX4 standard committee defined that the cables should be tighter in electrical specifications. Therefore, CX4 standard is not appropriate when longer length (>10 Infiniband cable is required. And It’s recommended to use only cables that are designed to meet IEEE 802.3ak specifications.

Another aspect of the CX4 cable is the rigidity and thickness of the cable. The longer the length used, the thicker the cable is. CX4 cables must also be factory-terminated to meet defined specifications.

After comparison between IEEE802.3ae and IEEE802.3ak standards, here goes a picture about the cabling cost and distance considerations.

 cabling cost and distance considerations

Besides IEEE802.3ae and IEEE802.3ak standards, there also exists IEEE802.3an standard. Proposed in November 2002, IEEE802.3an defined 10GBASE-T using unshielded twisted-pair (UTP) style cabling. The goal of this copper standard is to improve the performance and distance of copper cabling at a cost that is lower or similar to fiber.

From the above introduction, the evolution of cabling technologies is associated with the evolution of 10GbE standards. As 10GbE deployment becomes a commonplace, it’s of great importance to make wise cabling strategies.

Conclusion

Spurred by the demand for faster application speeds, cabling technologies evolved to support the 10GbE standards, thus to better accommodate bandwidth-intensive applications and traffic types. With 10GbE technology being pervasive, it’s necessary to understand the the different 10GbE standards and cabling technologies (mentioned above). Fiberstore supplies 10GbE application solutions, transceivers, copper and fiber cables all included, like AFBR-703SDZ-IN2, a 10GBASE-SR SFP+ transceiver. For more information about 10GbE system solutions, you can visit Fiberstore.

Data Center 10 Gigabit Ethernet Cabling Options

With the dramatic growth in data center throughput, the usage and demand for higher-performance servers, storage and interconnects have also increased. As a result, the expansion of higher speed Ethernet solutions, especially 10 and 40 Gigabit Ethernet has been ongoing. For 10 Gigabit Ethernet solution, selecting the appropriate 10-gigabit physical media is a challenge, because 10GbE is offered in two broad categories: optical and copper. This article will introduce both optical and copper cabling options for 10 Gigabit Ethernet.

Fiber Optic Cables

Two general types of fiber optic cables are available: single-mode fiber and multimode fiber.

Single-mode Fiber (SMF), typically with an optical core of approximately 9 μm (microns), has lower modal dispersion than multimode fiber. It is able to support distances of at least 10 kilometers, depending on transmission speed, transceivers and the buffer credits allocated in the switches.

Multimode Fiber (MMF), with an optical core of either 50 μm or 62.5 μm, can support distances up to 600 meters, depending on transmission speed and transceivers.

When planning data center cabling requirements, be sure to consider that a service life of 15-20 years can be expected for fiber optic cabling. Thus the cable chosen should support legacy, current and emerging data rates.

10GBASE-SR — a port type for multimode fiber, 10GBASE-SR cable is the most common type for fiber optic 10GbE cable. It is able to support an SFP+ connector with an optical transceiver rated for 10GbE transmission speed. 10GBASE-SR cable is known as “short reach” fiber optic cable.

10GBASE-LR — a port type for single-mode fiber, 10GBASE-LR cable is the “long reach” fiber optic cable. It is able to support a link length of 10 kilometers.

OM3 and OM4 are multimode cables that are “laser optimized” and support 10GbE applications. The transmission distance can be up to 300 m and 400 m respectively.

Copper Cables

Common forms of 10GbE copper cables are as follows:

10GBASE-CR — the most common type of copper 10GbE cable, 10GBASE-CR cable uses an attached SFP+ connector and it is also known as a SFP+ Direct Attach Copper (DAC). This fits into the same form factor connector and housing as the fiber optic cables with SFP+ connectors. Many 10GbE switches accept cables with SFP+ connectors, which support both copper and fiber optic cables.

Passive and Active DAC — passive copper connections are common with many interfaces. As the transfer rates increase, passive copper does not provide the distance needed and takes up too much physical space. So the industry is moving towards an active copper type of interface for higher speed connections. Active copper connections include components that boost the signal, reduce the noise and work with smaller gauge cables, improving signal distance, cable flexibility and airflow.

10GBASE-T — 10GBASE-T cables are Cat6a (category 6 augmented). Supporting the higher frequencies required for 10GbE transmission, category 6a is required to reach the distance of 100 meters (330 feet). Cables must be certified to at least 500 MHz to ensure 10GBASE-T compliance. Cat 6 cables may work in 10GBASE-T deployments up to 55 meters (180 feet) depending on the quality of installation. Some 10GbE switches support 10GBASE-T (RJ45) connectors.

When to Use Different Type of 10GbE Cables

To summarize, currently the most common types of 10GbE cables use SFP+ connectors.

  • For short distances, such as within a rack or to a nearby rack, use DAC with SFP+ connectors, also known as 10GBASE-CR.
  • For mid-range distances, use laser optimized multimode fiber cables, either OM3 or OM4, with SFP+ connectors.
  • For long-range distances, use single-mode fiber optic cables, also known as 10GBASE-LR.

The use of The MPO In 10GBASE-SR and 40GBASE-SR chanels

Purpose

The purpose of this document is to describe the usage and reason behind the development and characteristics of the MPO to be utilized in 10GASE-SR and 40GBASE-SR4 chanels.

Background

MPO connectivity has become widely used throughout the industry not only to reduce cable density, but also to prepare for the migration from 10GBASE-SR to 40GBASE-SR.

With the 10GBASE-SR transmission, there are two fibers associated with the channel one fiber for transmit and one fiber for receive. This configuration is often referred to as a duplex channel. The polarity of these channels (TX to RX) is relatively easy to manage from end to end and if polarity correction is required, it is easy to accomplish in the field by rearranging the fibers in the duplexing clip. Also, when two of these connectors need to be mated, an adapter with a split sleeve is used to align the ferrules of the two connectors. Shown below is a typical 10GBASE-SR Method A channel.

10GBASE - SR Method A Channel

In an existing 10G Ethernet fiber infrastructure, LC to MPO cassettes are replaced with MPO adapter panels and LC to LC patch cords are replaced with MPO patch cords during migration to 40G Ethernet. In this example, three different types of patch cords are required for the migration: Method A/Female to Male, Method A/Male to Male, and Method B/Female to Male. Using patch cords terminated with MPO Connectors, only one type of patch cord needs to be purchased and stocked, and can be configured on the fly to replace any of the three needed patch cords.

In the 40GBASE-SR transmission, there are eight fibers associated with the channel four fibers for the TX signal and four fibers for the RX signal. With multiple fibers being utilized, the polarity of the channel becomes harder to manage from end to end. Additionally, mating of two MPO connectors is not completed with an adapter with a split sleeve but rather with alignment pins that are a fixture on the MPO connector. One MPO connect or has alignment holes (this connector is referred to as a female MPO) and the other MPO connector has alignment pins.(this connector is referred to as a male MPO).

These two connectors are mated together in a genderless MPO adapter. Figure 2 shows a typical 40GBASE-SR Method A channel.

40GBASE-SR4 Method A Channel

When using MPO based connectivity in the 10G channel, the standard, ANSI/TIA-568C.1-7, calls for a female MPO horizontal cabling in frastructure (as shown in Figure 1) and a male MPO cassette. The male MPO is located within the cassette to protect the fragile alignment pins from damage during installation. In a 40G channel configuration, cassettes are not used and therefore cannot serve to protect the pins. Consequently, in the 40G channel configuration the standard calls for male MPO horizontal cabling (as shown in Figure 2) to protect the alignment pins on the back side of the adapter module rather than have them exposed to possible damage on the end of a patch cord. Male connectors on patch cords pose an additional operational risk to QSFP+ ports should a male connector be inserted due to the QSFP+ ports being configured as male to protect the pins within the port. The following is the products about 40G QSFP+ MTP MPO to QSFP+ Assembly from Fiberstore.

MTP trunk cable

QSFP+ MTP/MPO fiber trunk cable assemblies are interconnecting QSFP+ transceivers operating within 40GBASE-SR parallel optics networks.QSFP+ transceivers utilize 12Fibres MPO/MTP interface and perform 40G transmission using 4 x 10G channels (8 fibres: 4 x TX and 4 x RX ).Fiberstore MTP/MPO QSFP+ assemblies are built with highest quality components. Standard MTP/MPO as well low loss Elite versions are offered featuring low insertion loss for demanding high speed networks where power budgets are critical.

Considering this discussion, in order to comply with the ANSI/TIA-568C.1-7 cabling guidelines and provide the optimal pin protection when migrating from a 10G to 40G cabling configuration, the MPO connectors associated with the horizontal cabling infrastructure must be changed from female to male. Given that existing MPO connectivity does not allow for this alteration in the field without significant risk of fiber or connector damage, ii seems that the cabling in the horizontal cabling infrastructure would need to be changed out.

In the Method A configuration shown in Figure 2, there are also two different MPO patch cords necessary to complete the 40G channel. Not only does the horizontal cabling MPO change from female to male, but a Method A cord and Method B cord are needed at the ends to complete the channel to ensure proper polarity.

A Method B configuration holds the same gender issues as Method A when migrating from 10G to 40G, but does not need the two different MPO patch cords to complete the channel.

Testing is another challenge present with MPO horizontal solutions. Some testers have a fixed male MPO interface while others have a fixed female MPO interface. In both cases the preferred one jumper testing method, Method B, per TIA-568-C (TIA-526-14A and TIA-526-7) cannot be used for both the male horizontal and female horizontal cabling infrastructures. In the case where the MPO interface on the tester does not match the MPO in the horizontal infrastructure, a three jumper method would need to be utilized. The three jumper method introduces more variability and possibility for error in the testing.

For example, Figure 3 shows a tester with fixed Male MPO interfaces on the source and meter units. When setting the reference, you will need to use a female to female MPO reference cord. After setting the reference, in order to test a female horizontal cabling infrastructure, a third reference cable with a male end would need to be introduced to properly test the horizontal cabling infrastructure.

In any of these cases changing either the polarity or gender of the standard MPO connector in the field is not recommended due to the complex construction of the connector. Trying to change either of these characteristics in the field is extremely difficult and may lead to damage to the fiber exposed when attempting to replace the connector housing.

MTP MPO Fiber Cable is offered for various applications for all networking and device needs like 100G/40G modules. It uses a high-density multi-fiber connector system built around precision molded MT ferrule. Fiberstore MPO fiber cables are available in UPC and APC finishes, support both multimode and single mode applications, and optional lengths available. Our MTP/MPO fiber cable is with push connector IEC 61754-7 and TIA/EIA 604-5A compliant and offer low cost per termination for high density applications. The MPO/MTP fiber cables are tested with guaranteed quality, and they can be installed easily, which saves time and money.