GLC-SX-MM vs GLC-SX-MMD vs GLC-SX-MM-RGD vs SFP-GE-S

GLC-SX-MM, GLC-SX-MMD, GLC-SX-MM-RGD, and SFP-GE-S are popular multimode SFP transceivers for 1G connectivity. They are commonly used in Cisco networking devices for short-reach applications. However, because they are very similar, many IT managers need clarification about the specifications and differences.

If you’re one of them, you’ve come to the right place. In this post, we’ll compare these transceivers to help you differentiate them. Please note that the information we provide is for reference only. We suggest ordering directly from Cisco or its distributor if you want to buy the original SFP module.

However, if you prefer to avoid paying high prices for the original ones, buy third-party compatible SFP transceivers from a reliable supplier like Optcore. They may surprise you with a high price-cost ratio.

Before we dive into the comparison, let’s first understand some basic information that will help us classify the differences.

What is GLC-SX-MM?

GLC-SX-MM typically stands for Cisco 1000BASE-SX short wavelength SFP module. It is also a part number of compatible 1000BASE-SX SFP transceivers with the same function and performance supplied by many other 3rd party vendors. GLC-SX-MM allows users to use existing cable runs in distances up to 550m on 50/125 OM2 MMF, 220m on 62.5/125 OM1 MMF, and 1km over 50/125 OM3 fiber cables.

It’s important to note that GLC-SX-MM does not have a DOM/DDM function. It means you cannot access the transceiver’s real-time parameters, such as voltage, current, temperature, transmitter power, and receiver value.

What is GLC-SX-MMD?

GLC-SX-MMD is one of the most commonly used standard Cisco SFP modules. It is a hot-swappable input/output device plugged into a Gigabit Ethernet port. It is an improved version of the GLC-SX-MM, including Digital Optical Monitoring (DOM) to monitor the transceiver status. The GLC-SX-MMD operates over multimode fiber (MMF) and can reach distances up to 550 meters.

The only difference between GLC-SX-MM and GLC-SX-MMD is the DOM function. GLC-SX-MMD provides a built-in DOM function that allows the network administrator to manage and diagnose the transceiver intelligently and efficiently.

What is GLC-SX-MM-RGD?

GLC-SX-MM-RGD is the rugged version of GLC-SX-MMD. In this case, “RGD” stands for Rugged grade, which supports an industrial operating temperature of 40~85°C. It is also a 1000BASE-SX SFP module with a broader operating temperature for a rugged environment, targeting used for industrial ethernet switches and routers.

Because GLC-SX-MM-RGD supports industrial-grade environments, it is made with specialized materials and undergoes rigorous testing to ensure reliability. Therefore, the pricing is more expensive than that of the standard GLC-SX-MMD. Remember to choose GLC-SX-MM-RGD when you use the Cisco industrial switches. Otherwise, then GLC-SX-MMD may be the more cost-effective option.

What is SFP-GE-S?

SFP-GE-S also supports DOM but with an extended temperature of -5~85°C for fiber connection application in a harsh environment with a higher cost. Compared with GLC-SX-MM-RGD, it costs less but still supports 85°C temperature.

GLC-SX-MM vs GLC-SX-MMD vs GLC-SX-MM-RGD vs SFP-GE-S: What are the differences?

Features	GLC-SX-MMD	GLC-SX-MM	GLC-SX-MM-RGD	SFP-GE-S
Appearance	Same	Same	Same	Same
Transceiver Type	SFP Module	SFP Module	SFP Module	SFP Module
Wavelength	850 nm	850 nm	850 nm	850 nm
Reach	550 m	550 m	550 m	550 m
Fiber Type	Multimode Fiber (MMF)	Multimode Fiber (MMF)	Multimode Fiber (MMF)	Multimode Fiber (MMF)
Connector Type	LC Duplex	LC Duplex	LC Duplex	LC Duplex
Data Rate	1.25 Gbps	1.25 Gbps	1.25 Gbps	1.25 Gbps
Cabling Type	Ethernet 1000Base-SX	Ethernet 1000Base-SX	Ethernet 1000Base-SX	Ethernet 1000Base-SX
DOM Support	Yes	No	Yes	Yes
Operating Temperature	0°C to 70°C (Commercial Grade)	0°C to 70°C (Commercial Grade)	-40°C to 85°C (Industrial Grade)	-5°C to 85°C (Extended Grade)
Storage Temperature	-40°C to 85°C	-40°C to 85°C	-40°C to 85°C	-40°C to 85°C
Compatibility
Power Consumption	0.8 W	0.8 W	0.8 W	0.8 W
Weight	0.025 kg	0.025 kg	0.025 kg	0.025 kg
Price (3rd Party Replacement)	US$6.00	US$6.00	US$7.00	US$7.00

Table 1: GLC-SX-MM vs. GLC-SX-MMD vs. GLC-SX-MM-RGD vs. SFP-GE-S Comparison

The table above shows that those four models are similar in complying with the same protocols, form factor, data speed, compatibility, appearance, fiber type, wavelength, and weight.

The main differences are the DOM function and operating temperature.

GLC-SX-MM does not support DOM function, while the others support DOM.

GLC-SX-MM and GLC-SX-MMD are commercial transceivers for standard Ethernet switches. SFP-GE-S is an extended temperature transceiver, while GLC-SX-MM-RGD is an industrial temperature transceiver.

Before buying a new SFP transceiver, you should know your existing networking device, link distance request, and money budget. Then, decide which one is best for you.

Conclusion

The above comparison shows that the GLC-SX-MM is the old 1000BASE-SX SFP transceiver without DOM function. It features no DOM function, which is not in line with the trend of the intelligent optical module; therefore, it is at the end of the sale and has now upgraded to GLC-SX-MMD, which features a DOM function.

The GLC-SX-MMD is the most popular multimode 1G SFP transceiver for low-cost fiber networking.

Here are some quick tips on choosing the suitable multimode SFP module.

GLC-SX-MMD will be the best choice for most general Cisco switch applications.
If you use the Cisco industrial switches, GLC-SX-MM-RGD is the most suitable.
GLC-SX-MM is ending sale, so replace it with GLC-SX-MMD. GLC-SX-MMD is compatible and adds a DOM function for the enhanced monitor.

Optcore offers third-party SFP transceivers 100% compatible with GLC-SX-MM, GLC-SX-MMD, GLC-SX-MM-RGD, and SFP-GE-S. All SFPs have passed the compatibility test in target switches and are provided at the best price and high quality.

Are you clear about their difference and similarities now? If you still have questions, leave your comments in the below section. We are happy to provide any help.

Note: This article was initially published in April 2019 and has been updated for comprehensiveness.

Read more:

Optical Transceiver

GLC-SX-MM vs GLC-SX-MMD vs GLC-SX-MM-RGD vs SFP-GE-S, What Is The Difference?