Cabling Solutions for 1 GbE and 10 GbE

Ethernet technology has continually evolved in order to meet the never-ending requirement for faster rates of data transmission. The demand for faster application speeds has also spurred technological evolution on data carrying techniques. As such, copper and fiber transmission standards have progressed, providing greater bandwidth for transporting data over Ethernet architectures with reduced cost and complexity. This article highlights the cabling solutions for 1 Gigabit Ethernet and 10 Gigabit Ethernet.

 

1 Gigabit Ethernet Cabling

 

For 1 Gigabit Ethernet cabling, both fiber and copper cable connections are available.

Fiber Cabling

 

The optical fiber cables are usually used for longer connections. Optical fiber connections are constructed with a combination of a transceiver, which receives digital signals from the Ethernet device (switch or adapter card) and converts them to optical signals for transmission over the fiber. The most widely used transceiver for 1 Gigabit Ethernet is SFP (small form factor pluggable). For instance, the Cisco GLC-LH-SMD 1000BASE-LX/LH SFP can support transmission distance up to 10 kilometers.

The difference in cable choices comes from the distance limitations encountered with the various types of optical transmission. Short range and long range are the two different commonly available types. Short range supports connections of up to 550 meters, while long range supports connections of up to 10 kilometers. Multimode fiber cables are typically used for short range transmission and single-mode fiber cables are used for long range transmission.

The final consideration on the fiber cable is the connector type. The main differences among types of connectors lie in dimensions and methods of mechanical coupling. Multimode fiber cables and single-mode fiber cables require different connectors. SC and LC connectors are the most common types.

Copper Cabling

 

For copper cables supporting 1 Gigabit Ethernet, the Category 5 unshielded twisted pair (Cat5-UTP) is utilized. With a RJ45 connector on either end, Cat 5 can support connections of up to 100 meters. Cat5e, an enhanced version of the Category 5, is the most used Ethernet cabling today. For lower speed (10 or 100 Mbps) connections, only two of the four pairs in Cat 5 cables are used. For 1 Gigabit Ethernet, all four pairs are used. The following picture shows the 1G and 10G application in an enterprise data center.

 

10 Gigabit Ethernet Cabling

 

For 10 Gigabit Ethernet cabling, the cabling choices are nearly the same with the 1 Gigabit Ethernet. The fiber options are very similar. The transceivers are somewhat different.

Fiber Cabling

 

An enhanced version of the SFP transceivers was standardized for use with 10 Gigabit Ethernet and named SFP+ (enhanced small form factor pluggable). SFP+ has the same mechanical characteristics as the SFP transceiver. It is capable of supporting the higher speed—10 Gbps. Besides SFP+ transceiver, XFP (10 Gigabit small form factor pluggable) transceiver also can support 10 Gigabit Ethernet. Compared with XFP, the SFP+ has smaller form factor allowing for much more dense packaging of ports on switches. Moreover, the direct attach copper cable, supporting 10Gbps Ethernet data transmission, has two SFP+ connectors on both end. This 10G direct attach copper cable like Cisco SFP-H10GB-CU5M supports transmission distance up to 12-15 meters, which is often more than enough for interconnecting systems in racks in data centers. With these two capabilities, SFP+ has become the predominant 10 Gigabit Ethernet connector type.

For 10 Gigabit Ethernet fiber connections, the same optical fiber as 1 Gigabit Ethernet is used. The short range fiber cables can support connections of up to 300 meters and long range fiber cables can support connections of up to 2 kilometers. Besides these two, a new option is also available—extended range (for connections of up to 10 kilometers).

LC and SC are also the common connector types. Note that these cables can be connected to either XFP or SFP+ transceivers. The connector type defines the mechanical specifications of the fiber-to-transceiver interface. Thus, one could have a XFP transceiver on one end of a 10G Ethernet fiber cable and a SFP+ transceiver on the other end. As long as the cable type and connector type match, there is no problem.

Copper Cabling

 

For 10 Gigabit Ethernet cabling, the standards body determined that even the enhanced Cat5e UTP traditional Ethernet cable would not be able to carry the signal reliably for any significant distance. So a new specification, still using RJ45 connectors, was introduced and named 10GBASE-T. This calls for a 4-wire twisted pair cable with even more stringent limitations on cross-talk. It is called Cat 6a. 10GBASE-T cables for up to 100 meters are supported.

Summary

 

For 1 Gigabit Ethernet connection, SFP transceiver, fiber optic cables and copper cables are the choices. For 10 Gigabit Ethernet connection, 10G SFP+, 10G XFP, optical fiber cables as well as copper cables are able to meet the requirements. Fiberstore, a professional company in the field of optical network devices and interconnection, supplies various fiber optic transceivers, fiber optic cables and copper cables. Lots of the fiber optic products, such as SFP-10G-ER SFP+, have large inventory and low price. For more detailed information about us, please visit www.fs.com.

Article source: www.fiberopticshare.com

Introduction to DDM Function of GLC-LH-SMD Transceiver

Basic Introduction

As is known to all, Cisco GLC-LH-SMD is the replacement of GLC-LH-SM. It consists five parts: the LD driver, the limiting amplifier, the digital diagnostic monitor, the 1310nm FP laser and the PIN photo-detector. Supporting a data rate of 1.25 Gbps, this GLC-LH-SMD SFP transceiver operates on standard single-mode fiber optic link spans of up to 10 km and up to 550 m on any multimode fibers. You may say the letter “D” is the only difference between the two, and ask what’s the meaning of “D” and why GLC-LH-SMD can take the place of GLC-LH-SM? This article will give you an answer by introducing its additional function—DDM (digital diagnostic monitoring).

What Is DDM?

Actually, the letter “D” stands for the digital diagnostic monitoring function according to the industry standard multi-source agreement (MSA) SFF-8472 and is known as digital optical monitoring (DOM). A fiber optic transceiver with DDM is higher end than the one without DDM function. The DDM function gives end users the ability to monitor real-time parameters of the optical transceivers, such as the transceiver temperature, laser bias current, transmitted optical power, received optical power and transceiver supply voltage. Most of today’s fiber optic transceivers have this function.

Functions of DDM

After knowing what digital diagnostic monitoring is, next we’d move to the functions of DDM or what DDM can actually do. Literally, DDM is able to provide component monitoring on transceiver applications in details like the real-time parameters listed in the previous paragraph. But that’s not all functions of DDM. The SFF-8472 added DDM interface and outlined that DDM interface is an extension of the serial ID interface defined in GBIC specification and the SFP MSA. This DDM interface defines a sophisticated system of alarm and warning flags, which alerts end users when particular operating parameters are inconsistent with the factory-set normal range. So the DDM interface is also able to let the end users have the ability to achieve fault isolation and failure prediction. The three functions (component monitoring, fault isolation, failure prediction) will be stated in more details below.

Component Monitoring

Component monitoring is the most familiar function to users. Usually the key parameters of the optical transceivers—transceiver temperature, transceiver supply voltage, laser bias current, transmit average optical power and received optical modulation amplitude (OMA) or average optical power, will be monitored. If the transceiver’s specified operating limits are exceeded and compliance cannot be ensured, these real-time diagnostic parameters will alert the system.

Fault Isolation

Fault isolation is the second function of DDM. The DDM is able to isolate the particular location of fault in an optical network system. With the combination of the DDM interface status flags, transceiver hard pins and diagnostic parametric monitor data, it’s easy to pinpoint the specific location and cause of a link failure.

Failure Prediction

Failure prediction is the last function of DDM. Based on the transceiver parametric performance, the DDM can be helpful in failure prediction on fiber optic links. Device faults and high error rate conditions are the two basic types of failure conditions which can be seen on optical transceivers. Device fault means non-operation or malfunction. With the nature of semiconductor lasers, this is usually applied to transmitter performance. High error rate conditions refer to the operating conditions that transceiver is operating at its signal-to-noise limit. This is typically applied to optical fiber performance.

Summary

After reading the above statement, have you got a better understanding about the DDM function of GLC-LH-SMD? Fiberstore’s GLC-LH-SMD small form factor pluggable (SFP) transceiver is compatible with the small form factor pluggable multi-source agreement (MSA). This transceiver is programmed to be fully compatible and functional on a wide range of Cisco equipment. All Cisco compatible GLC-LH-SMD 1000BASE-LX/LH SFP transceivers from Fiberstore are all tested on Cisco original equipment to ensure their superior quality and performance (see the picture above). Besides the GLC-LH-SMD SFP transceiver, many other Cisco compatible transceivers provided by Fiberstore, such as SFP-10G-LR and QSFP-40G-CSR4, have to be tested before arriving to customers. For more detailed information about us, please visit www.fs.com or contact over sales@fs.com.

Article source: www.fiberopticshare.com/introduction-ddm-function-glc-lh-smd-transceiver.html