Tag Archives: 1000BASE LX SFP

GBIC vs SFP—When to Choose What?


GBIC and SFP are both a kind of hot-pluggable optical transceiver which is mainly used to convert between the optical signal and electrical signal. GBIC stands for Gigabit Interface Converter. SFP is short for Small Form-factor Pluggable. Usually, SFP is considered as an upgraded version of GBIC module. However, GBIC and SFP are equal in performance. The only major difference between them is their size. SFP module is much smaller than GBIC module. For this reason, the SFP is also called mini GBIC in most cases.

These years, due to the small size of SFP, GBIC module is being replaced by SFP. Why is this happening? In fact, the most common reason is that the big size of GBIC module was not feasible to provide more number of interfaces on a line card or a switch since it occupies more space. In order to resolve this issue people came up with SFPs which were smaller in size hence you can have more interfaces on the same line card or switch compared to GBICs. Let’s take an example, have you ever heard of a 48 port GBIC line card on 6500 switch. The answer is no, because it’s not feasible to have 48 big GBIC interfaces on the form factor of the line card. But a 48 port SFP line card exists.

gbic module

Knowing the differences between these two modules, then which one should you choose? In general, it actually depends on the line card or the switch you have. Usually, the line cards and switches comes with empty GBIC or SFP slots where you need to purchase the GBIC module or SFP modules respectively and insert in those empty slot. However, if you already have a switch or line card which has GBIC slots you have to use GBICs, simply because SFPs won’t fit in and vice versa.

Another case where you don’t have a switch or line card and want to make a decision whether to use a GBIC or SFP will actually depend on the number of interfaces required and availability of the switches and line cards specific model. For example, if you want two fiber interfaces on a line card on 6500 switch, you won’t go for a 48 port SFP line card, instead you’ll use a 2 port GBIC line card. If you need some 24 fiber interfaces you won’t use a 16 (or 18 not sure) port GBIC line card, you’ll use a 48 port SFP line card.

After reading this article, you may get a clear understanding of whether to use SFP module or GBIC module. Fiberstore provides all kinds of SFP modules, such as 1000BASE-T SFP, 1000BASE SX SFP, 1000BASE LX SFP etc. If you need to buy GBIC modules, I also recommend you to visit Fiberstore. All their GBIC modules come with a lifetime advance replacement warranty and are 100% functionally tested.

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Are There Any Differences Between LX, LH and LX/LH?


We usually see LX SFP, LH SFP and LX/LH SFP on many websites, and many people show their confusion about them. Whether they are the same or different? If they are dissimilar, what differences between them on earth?

The Commonly Used 1000BASE-X Standards about Ethernet
Ethernet was the result of the research done at Xerox PARC in the early 1970s. Ethernet later evolved into a widely implemented physical and link layer protocol. Fast Ethernet increased speed from 10 to 100 megabits per second (Mbit/s). Gigabit Ethernet was the next iteration, increasing the speed to 1000 Mbit/s. The initial standard for Gigabit Ethernet was produced by the IEEE in June 1998 as IEEE 802.3z, and required optical fiber. 802.3z is commonly referred to as 1000BASE-X, which is used in industry to refer to Gigabit Ethernet transmission over fiber, where options include 1000BASE-SX, 1000BASE-LX, 1000BASE-LX10, 1000BASE-BX10 or the non-standard -EX and -ZX implementation.

Gigabit Ethernet 1000BASE-LX Optical Interface Specifications

1000base-lx/lh SFP1000BASE-LX is a fiber optic Gigabit Ethernet standard specified in IEEE 802.3 Clause 38 which uses a long wavelength laser (1,270–1,355nm). The 1000BASE-LX SFP is specified to work over a distance of up to 10 km over single mode fiber and it can also run over all common types of multimode fiber with a maximum segment length of 550 m. For link distances greater than 300 m, you must install a mode-conditioning patch cord between the transceiver and the MMF cable on both ends of the link.

1000BASE-LH and 1000BASE-LX/LH Optical Interface Specifications
LH refers to Long Haul. Many vendors use both of them for certain SFP modules, but they aren’t a Gigabit Ethernet standard at all. 1000BASE-LX/LH SFP can achieve a distance up to 20 km over single mode fiber. Unlike that, 1000BASE-LH SFP operates a distance up to 70 km over single mode fiber.

In a word, these three modules are all referred to Gigabit Ethernet transmission. Among them, the 1000BASE-LX is a standard, the other two just are terms widely used by vendors. Other long haul transmission standards include 1000BASE-LX10, 1000BASE-EX and 1000BASE-ZX. We can see their differences more clearly in the following chart:

Name  Medium wavelength Specified distance
1000BASE-LX/LH 9/125 Single mode fiber 1310nm  10km
1000BASE-LX 62.5/125, 50/125 Multi mode fiber 1310nm 550m
1000BASE-LX10 9/125 Single mode fiber 1310nm 10km
1000BASE-LH 9/125 Single mode fiber 1310nm 25~70km
1000BASE-EX 9/125 Single mode fiber 1310nm 40km
1000BASE-ZX 9/125 Single mode fiber 1550nm 70km

Related Article: Which Patch Cable Should I Choose for My Optical Transceiver?