FAQs About Cisco 1000BASE-LX/LH SFP Transceiver

Existing and emerging network technologies are driving the need for optical transceivers which support increased data rates in the data center. With the emergence of 1000BASE-LX specification, 1000BASE-LX/LH SFP transceiver module is widely used in optical network systems. Here are the most frequently asked questions we might have when using Cisco 1000BASE-LX/LH SFP (GLC-LH-SM or GLC-LH-SMD) transceivers.

1. Can 1000BASE-LX be compatible with 100BASE-LX?

1000BASE-LX and 100BASE-LX are very different standards. 1000BASE-LX SFP (GLC-LH-SMD) and 100BASE-LX SFP (GLC-FE-100LX) are two module types, one for GE and one for FE slots. The GLC-LH-SMD does not operate at 100Mbps. You will need to use a 100Mb module to connect to another device at 100Mb. Check optical transceiver compatibility with your equipment by reviewing the Cisco Fast Ethernet SFP module compatibility document and choose the one it says is compatible.

2. What is the difference between LH and LX modules?

The 1000BASE-LX, 1000BASE-LH and 1000BASE-LX/LH all refer to Gigabit Ethernet transmission. Among them, the 1000BASE-LX is a standard specified in IEEE 802.3 Clause 38 which uses a long wavelength laser, while the 1000BASE-LH and 1000BASE-LX/LH are just terms widely used by many vendors. Long Haul (LH) denotes longer distances while Long Wavelength (LX) denotes less energy which is obviously shorter distance. The 1000BASE-LX SFP modules compatible with the IEEE 802.3z 1000BASE-LX standard can achieve a distance up to 10km over single mode fiber. Unlike 1000BASE-LX SFP modules, 1000BASE-LH SFP modules operate at a distance up to 70km over single mode fiber.

3. Does 1000BASE-LX SFP work with 1000BASE-LH SFP? What does it mean if a module says like "Cisco 1000BASE-LX/LH SFP"?

Yes, the 1000BASE-LX works with the 1000BASE-LH. For instance, Cisco 1000BASE-LX/LH SFP is either made for single mode (long distance) / multimode (short distance). But this module can be used for both Single-mode and Multimode. The Cisco 1000BASE-LX/LH SFP, compatible with the IEEE 802.3z 1000BASE-LX standard, operates on standard single-mode fiber-optic link spans of up to 10 km and up to 550 m on any multimode fibers. When used over legacy multimode fiber type, the transmitter should be coupled through a mode conditioning patch cable.

4. GLC-LH-SM SFP to 1000BASE-LX GBIC won't link over MMF?

Cisco compatibility document says: "Some customers might be tempted to connect 1000BASE-LX/LH devices over short reaches of MMF jumper cables without MCP cables. There is a risk associated to this type of nonstandard deployment, especially when the jumper cable is an FDDI-grade or OM1 type. In such case the power coupled directly into a 62.5-micron fiber could be as high as a few dBm (typically 5 to 6 dBm), and if the jumper cable is short, the adjacent receiver will be saturated, causing high bit error rate, and eventually irreversibly damaged. We recommend the use of MCP, but if the customer remains reluctant to the deployment of MCP, a 5-dB attenuator for 1300nm should be used and plugged at the transmitter of the optical module on each side of the link."

5. Does GLC-LH-SMD work with GLC-LH-SM?

Yes. Both the GLC-LH-SM and GLC-LH-SMD transceivers support the IEEE 802.3 1000BASE-LX/LH standard and so are compatible with each other. The difference between the two is that the GLC-LH-SMD transceiver has additional support for Digital Optical Monitoring capability.

Fiberstore offers a wide range of 1000BASE-LX/LH SFP transceiver modules which are compatible with major brands, like Cisco, Juniper, Dell, Finisar, Brocade, or Netgear (AGM732F) in 10/20 km options. Fiberstore’s optical transceivers are able to fulfill enterprises, service providers, telecom operators and SAN providers to build and fulfill their existing and future network expansions. Besides the compatible 1000Base-LX/LH SFP modules, we also provide the 1000BASE-EX (like Cisco GLC-EX-SMD), 1000BASE-SX (like Cisco GLC-ZX-SM), 1000BASE-BX (like Cisco GLC-BX-D) and so on.

Fiberstore Pluggable Fiber Optic Transceivers

Pluggable fiber optic transceivers refer to hot-swappable or hot-pluggable optical transceivers which can be quickly plugged into an interface of fiber optical devices. An optical transceiver can best be described as a device that converts high-speed data from a cable source to an optical signal for communication over optical fiber. Optical transceivers are used to update the communications networks to manage broadband, to update the data center networks to make them manage traffic with higher speeds, and to implement the backbone network for mobile communications.

Pluggable fiber optic transceivers provide connectivity options for Ethernet over twisted pair copper and fiber optic cables with transition speeds from 100 Megabits per second to 100 Gigabits per second. Twisted pair copper transceivers support transmission distances of up to 100 meters and fiber optic transceivers support multi-mode and single-mode fiber optic cable types with transmission distances up to 120 kilometers. Followings are some of the most common types of pluggable transceivers from Fiberstore.

GBIC Transceivers

For transceivers that plugs into Gigabit Ethernet and links to a fiber optic network, the Gigabit Interface Converter (GBIC) is the standard and SFP is for small form factor pluggable transceiver. The GBIC transceiver module operates as an input and output transceiver and is linked with the fiber optic network generally through the optic patch cords. GBIC transceivers are deemed to be ideal for any interconnections over the Gigabit Ethernet centers and for switches environment. The converters are virtually intended for high performance and continuing interactions that have need of gigabit or fiber channel interconnections.

XENPAK Transceivers

XENPAK is the first MSA for 10 Gigabit Ethernet. The XENPAK MSA defines a fiber optic or wired transceiver module which conforms to the 10 Gigabit Ethernet standard of the IEEE 802.3 working group. XENPAK transceiver module is a hot-swappable, highly integrated and serial optical transceiver module for 10Gbit/s data transmission applications. It is designed to transmit and receive optical data of link length of 300m, 10km, 20km, 40km and up to 80km. 10G XENPAK solution includes dual fiber XENPAK, CWDM XENPAK and DWDM XENPAK transceivers which enable high port densities for 10 Gigabit Ethernet systems. A 70 pin electrical connector and a duplex SC connector optical interface assure that connectivity is compliant to the XENPAK MSA.

SFP Transceivers

SFP transceiver is a compact and hot-pluggable transceiver and a popular industry format jointly supported by many network component vendors. The devices are designed to use together with small form factor connectors and offer high speed and physical compactness, providing instant fiber connectivity for your networking gear. It is a cost effective way to connect a single network device to a wide variety of fiber cable distances and types. SFP transceiver modules are designed to support SONET/SDH, Fast Ethernet, Gigabit Ethernet, Fibre Channel and other communications standards.

SFP+ Transceivers

The small form-factor pluggable plus (SFP+) can be referred to as an enhanced version of the SFP that supports data rates up to 16 Gbit/s. SFP+ transceiver supports 8Gbit/s Fiber Channel, 10 Gigabit Ethernet and optical transport network standard OTU2. The SFP+ product family includes cages, connectors, and copper cable assemblies. The SFP+ transceiver modules are specified for 8Gbps/10Gbps/16Gbps Fibre Channel and 10-Gigabit Ethernet applications. Besides, converter modules for X2 and XENPAK ports are also available in Fiberstore. For example, the following Cisco CVR-X2-SFP10G compatible oneX converter module for X2 ports converts a 10 Gigabit Ethernet X2 port into a 10 Gigabit Ethernet SFP+ port. With the OneX converter module, customers have the flexibility to use the 10 Gigabit X2 interface port of a switch with X2 modules or SFP+ modules.

Fiberstore's pluggable optical transceivers include GBIC, SFP, XFP, SFP+, X2. CFP form factors are available as well. These high quality transceivers support for a large variety of cable types and transmission distances. Fiberstore also provide third-party compatible optical transceivers including 100BASE (like Cisco GLC-FE-100LX SFP), 1000BASE (like Cisco SFP-GE-S SFP), as well as 1G to 100G optical transceivers.