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Cisco SFP-10G-SR: All You Need to Know

December 13, 2012

Cisco, as one of the leading networking companies throughout the world, is dedicated to networking equipment design and manufacture. In the midst of its massive product lines, SFP+ modules including SFP-10G-SR have earned itself broad popularity and great reputation. 10G SFP+ modules with various protocols offer optimized 10 Gigabit Ethernet connectivity for diverse networking environments. Cisco SFP+ modules consist of Cisco SFP-10G-SR, SFP-10G-LR (LRM), SFP-10G-ER and SFP-10G-ZR, etc. This article will focus on everything about the SFP-10G-SR Cisco transceiver module.

Module Wavelength (nm) Distance Fiber Mode Interface Temperature (℃)
SFP-10G-SR 850 300m MMF LC Duplex 0℃-70℃
SFP-10G-LR 1310 10km SMF LC Duplex 0℃-70℃
SFP-10G-SR-S 850 300m MMF LC Duplex 0℃-70℃
SFP-10G-SR-X 850 300m MMF LC Duplex -40℃-85℃
SFP-10G-LR-S 1310 10km SMF LC Duplex -40℃-85℃
SFP-10G-LR-X 1310 10km SMF LC Duplex -40℃-85℃
SFP-10G-LRM 1310 220m MMF LC Duplex 0℃-70℃
SFP-10G-ER 1550 40km SMF LC Duplex 0℃-70℃
SFP-10G-ER-S 1550 40km SMF LC Duplex 0℃-70℃
SFP-10G-ZR 1550 80km SMF LC Duplex 0℃-70℃
SFP-10G-ZR-S 1550 80km SMF LC Duplex 0℃-70℃

Cisco SFP-10G-SR Deep Dive

Cisco 10GBASE-SR SFP module belongs to Cisco 10G SFP+ modules family, hence it persists all the features and benefits of 10G SFP+ modules: fit for 10GBASE Ethernet application, Cisco SR optics have the smallest hot-swappable 10G form factor, which can be directly plugged into the Ethernet SFP+ port on a Cisco switch (no need to power down when installing or replacing). Equipped with DOM (digital optical monitoring ) capability, Cisco SFP-10G-SR ensures strong diagnostic capability. When it comes to link performance, Cisco 10GBASE-SR SFP module supports a link length of 26 meters on standard multimode fiber (MMF). And the reach can be extended up to 300 m with laser-optimized OM3 MMF and to 400 m with OM4 MMF.


Cisco 10GBASE-SR SFP module is a Class 1 laser product. It fully complies with the multi-sourcing agreement (MSA) which enables it to work in all MSA compliant platforms. Note that this 10GBASE-SR module must be operated within the specified temperature and voltage limits, and the interface of the transceiver module should be terminated with an optical connector or a dust plug.

Which Switch Can Cisco SFP-10G-SR Module Be Used?

Cisco SFP-10G-SR transceiver is widely used in many Cisco switches that are loaded with native SFP+ ports, including but not limited to Catalyst 2360 series, Nexus 2000/3000 series, Catalyst 2960-S series, Catalyst 3650 Series and etc. For the details, please refer to Cisco 10-Gigabit Ethernet transceiver modules compatibility matrix.

Which Patch Cable Should I Use for SFP-10G-SR?

In that 10GBASE-SR SFP module has LC duplex connector operating over 850nm for short reach, a multimode LC-LC fiber patch cable is the best fit. Let’s explore some differences between single-mode fiber (SMF) and multimode fiber (MMF). Single-mode fiber is used for data transmission over long distances—the light in which propagates along a straight line so light spread and reflection is kept minimum, hence enabling longer-range transmission (up to 80 km) with little attenuation. Multimode fiber (MMF), however, carries multiple light rays which inevitably lead to more light dispersion and reflection, making it the choice of short-range connection (up to 2 km).

Single-mode fiber (SMF)
Multimode fiber (MMF)
Path of Light
single-mode fiber
multimode fiber
Light Source
Laser light source
LED light source
Core Diameter
9/125 µm
50/125 µm, 62.5/125µm
Transmission Distance
5-80 km
2km (100M), 1Km(1G/s), 550m(10G/s)
1310nm, 1550nm
850nm, 1310nm
Bandwidth & Attenuation
Higher bandwidth & lower attenuation
Lower bandwidth & higher attenuation
Orange (OM1, OM2) Aqua (OM3, OM4)
Telecom & CATV Networks
LAN, Security System & General Fiber Networks

Can I Use a Compatible SFP-10G-SR Module?

The answer is yes - just pick a trustworthy third-party vendor, then you would get compatible Cisco SR optics with equal performance as the original one. A Cisco compatible module and a Cisco-branded one alike, are built to the same specs and strict standards of MSA (Multi-Source Agreement). And most third-party compatible optics are even built and assembled in the exact same plants as first-party equipment, but with roughly 1/10 the cost (of the brand ones). It is hence natural that most users now are more inclined to choose third-party optics. However, not all third-party optics are created equal. FS.COM knows the importance of compatibility and addresses every step in our manufacturing and sourcing process: each transceiver module is tested in original-brand switches in the professional test center. You can hence rest assured by using optical modules backed by FS.COM.

Cisco N7K-M132-12L test bed

Common Questions About SFP-10G-SR

As aforementioned, there exists a dazzling array of 10G SFP+ modules, making it hard to distinguish and select. So here we offer complete FAQs on some frequently asked questions.

Q: What's the difference of SFP-10G-SR-S vs SFP-10G-SR?

A: When it comes to SFP-10G-SR-S vs SFP-10G-SR, the SR-S belongs to Cisco “S-Class” optical transceivers—it has a reduced feature set thus costs significantly less than other multigigabit SFP+ standards. “S-Class” modules are transceivers that only incorporated the features most commonly seen in enterprise and data center applications. SR-S has reduced temperature tolerances and only supports Ethernet. So for most standard applications, S-Class is fine and will save some money compared to other Cisco transceivers.

Q: What does -X mean, as in SFP-10G-LR-X or SFP-10G-SR-X?

A: -X here means it has extended ability to operate under wider temperature variation, from -40°C to 85°C (-40°F to 365°F). By comparison, standard transceivers are generally restricted to operating temperatures from about 0°C to 70°C (32°F to 158°F). There is no other significant difference from the standard versions, and no reason to use -X equipment unless you’re operating in extreme temperatures.

Q: What's the difference of SFP-10G-SR vs SFP-10G-LR?

A: Both of these two SFP+ modules are compliant with MSA, and support the same network protocols. The difference is that SR stands for Short Range while LR stands for Long Range. SR transceiver operates at 850 nm and is used with multimode fiber—serving as the best fit for high speeds over relatively short distances. With laser-optimized OM3 and OM4 fiber patch cable, the reaching of a SFP-10G-SR Cisco can be extended to 300 m and 400 m respectively. SFP-10G-LR uses a DFB laser with 1310 nm suitable for single-mode fiber, which allows it to reach about 10 km.

Q: What's the difference between SFP-10G-SR and SFP-10G-LRM?

A: LRM here in the SFP-10G-LRM refers to “Long Reach Multimode”. This type of optical module is primarily used for long-distance multi-point mode of connection. LRM operates on 1310am lasers, while SR uses 850nm lasers for short-range connection, supporting link length over 300m over multimode fiber OM3 and OM4.

Q: What are SFP-10G-ER and SFP-10G-ZR?

A: Both of these two SFP+ transceivers are extremely long-range variations. SFP+ ER (Extended Reach) is capable of reaching up to 40km over single-mode fiber. ZR pushes the range of single-mode ER fiber out to 80km, or about 50 miles. Several hardware manufacturers (including Cisco) have their own implementations of ZR, but they aren’t necessarily cross-compatible.

Q: What's the difference between SFP-10G-SR and SFP-10G-T?

A: They both are hot-pluggable devices with a calculated soft-start. They are interoperable with any SFP+ connector system and cage. But they have entirely different performances when it comes to the 10G switches. SFP-10G-T uses the Cat6a cables for a 30+ link length, while 10GBASE-SR SFP module uses LC connectors over OM3 cables, supporting link length of 300 m and above.

Q: How about SFP-10G-SR vs FET-10G?

A: SFP-10G-SR and FET-10G transceivers are exactly the same from hardware perspective, just with different coding. FET-10G has special coding features that are recognizable and usable only with Nexus 2000, Nexus 5000 and Nexus 7000 series.

Q: What is the difference between SFP short-range and X2 short range?

A: Both support link lengths to 300m over MMF and use 850 nm lasers. But they are two different packages belonging to the Cisco 10G family. SFP optical modules belong to the SFP package and are used in SFP compatible slots. And X2 modules are with X2 package and used in X2 compatible slots – they use SC connector while the SFP transceiver is paired with a dual LC connector.

Q: Can we interconnect SFP-10G-SR to XENPAK-10GB-SR or X2-10GB-SR?

A: The answer is yes—you just need the correct optic on each side. If your optics are single-mode you need single-mode patch cords, whereas multimode optics require multimode patch cables. SFP-10G-SR, XENPAK-10GB-SR and X2-10GB-SR are all multimode optics, so a multimode fiber can be used to make the connection.

Q: Is it possible to connect X2-10GB-LR to SFP-10G-SR?

A: Definitely No. Cisco X2-10GB-LR module supports a link length of 10 km on standard single-mode fiber (SMF, G.652). However, Cisco SR optics support a link length of 300m on OM3 multimode fiber (MMF,OM3) and 400m on OM4 multimode fiber (MMF, OM4). We can only connect optical modules with the same wavelengths, i. e. SR to SR or LR to LR.

Q: Do SFP-10G-SR modules support GE?

A: Yes—10GBASE-SR SFP modules can support GE speeds, but this depends also on host system port properties. In case of Cisco Catalyst switches it will not mostly work, but in some systems, you can configure a 10G port to run in GE mode and it will be supported by a transceiver module.

Q: Can we use SFP hardware in SFP+ slots?

A: It actually depends on the switch models. In most cases, SFP modules can work in SFP+ ports, but conversely, SFP+ optics do not work in SFP slots since it doesn’t support auto-negotiation. When plugging an SFP into a SFP+ port, the speed remains to be 1G instead of 10G. Notice that a SFP+ port never supports speed under 1G, so you can not insert a 100BASE SFP in an SFP+ port.

Q: Cisco SFP-10G-SR module, DAC or Cat5/6: which is the best option for short-range 10G connections?

A: Again, it depends. Each of the three solutions excel in this particular scenario. 10GBASE-T could be the only option when you already had copper cables in wall, or equipment you need to connect only has 10G copper ports. For very short distances like intra-rack or inter-rack connection (typically 0-50 m), DAC (Direct Attach Cable) or AOC (Active Optical Cable) would be the cost-effective choices. While for link length beyond 50 m, SFP-10G-SR transceiver and fiber patch cable are necessary.

Q: Is Cisco SFP-10G-SR transceiver supported on switches from other vendors?

A: As to the SFP-10G-SR compatibility, it also depends. Since most of host system vendors have no protectionism policy, they can fairly accept any MSA compatible transceiver in their systems. All of the protection algorithms come on top of MSA guidelines, therefore Cisco 10GBASE-SR SFP module will work on systems that compliant with MSA. However, Cisco SFP-10G-SR module will not be supported on systems using different proprietary algorithms.

Q: What is the price of SFP-10G-SR in the market?

A: When comparing OEM vs compatible SFP-10G-SR price, you may notice a rather huge gap between them. OEM modules are first-party optics branded by original vendors like Cisco, Juniper, Intel and etc. Usually equipment vendors subcontract production of these modules to OEM manufacturers, and attach their own logo on the modules, then selling these modules with 10 times and more markup. Compatible 10GBASE-SR modules made with the same spec and MSA standards perform equally as the branded ones, which has become a preferable choice for most users. The compatible SFP-10G-SR price may vary from vendors, so here we offer SFP-10G-SR price comparison.

Vendor CDW Router-Switch FS.COM 10Gtek 6COM FluxLight
Brand Cisco Cisco FS.COM 10Gtek 6COM FluxLight
Price $691.99 $262.00 $16.00 $19.88 $19.99 $54.00

Cisco SFP-10G-SR Modules Installation Guide

Installing SFP-10G-SR Module

  • Though data rates may be the same, one module may not be suited for a particular slot. So insert an SFP module preferably into an SFP slot only.

  • Carefully check the compatibility of each module before connecting it to any slot. If incompatible modules are inserted without caution, a system breakdown may happen. This can lead to monetary losses as well.

  • Check the network configuration; connect the modules that are best for the current configuration of the network.

  • Always clean the modules before installing, be it an SFP module or SFP+ module. This will prevent contamination in the system.

  • Do not expose your eyes to fiber optic equipment. They emit laser and infrared rays that may be harmful to you. If at all, you need to examine something, make sure that the light source is disconnected.

  • You can damage the electrostatic discharge, if not careful. In order to prevent it, always wear an antistatic wrist strap while handling the network equipment.

Removing SFP-10G-SR Module

  • It is not good to frequently pull out or insert the SFP module. This can badly affect the lifetime of the module.

  • If you need to remove the optical module, please pull out the rod first. Then, through the rod remove the optical module.

Cisco SFP-10G-SR Modules Troubleshooting

To diagnose SR optics problems, you can get statistics from the browser interface, the CLI (Command Line Interface) or an SNMP (Simple Network Management Protocol) workstation. The most common 10GBASE-SR module problems include these aspects:

1. Poor Performance (or Excessive Errors)

The possible causes of this problem may result from exceeded cabling distance or port statistics show excessive frame check sequence (FCS), late-collision, or alignment errors. To solve this, one can reduce the cable length to the recommended distances, and see your SR optics module documentation for cabling guidelines.

2. No Connectivity

This problem is most likely related to cabling. Using incorrect or bad cable, incorrect cable wiring, or STP (Shielded Twisted Pair) checking for possible loops may probably lead to this problem. When this problem occurs, you should first verify if the pinouts are correct for the application of cables, if not, just replace the cable with a tested good cable, then wait 30 seconds for the port LED to turn green.

3. Corrupted Software

It basically includes three situations: a. the port is placed in error-disabled state after a 10GBASE-SR is inserted. The best advice is to use a Cisco original SFP or 100% Cisco compatible SR optics (If you decide to use a third-party 10GBASE-SR SFP module, please ensure that your supplier is assured). b. device does not recognize the SFP-10G-SR module. Then you should first verify that the SFP module is not installed upside down, and then remove the SFP module to inspect if there is any physical damage in the module. c. excessive errors found in port statistics. If this is the problem, you can run adapter card diagnostic utility and wait 30 seconds for the port LED to turn green.


Cisco SFP-10G-SR optical module has become the best fit for securing short-range 10 Gigabit transmission in optical networks. It enables higher rack density, increased bandwidth and ease of use. If you’ve got a Cisco switch at hand but with a string budget for optics, FS SFP-10G-SR modules is your wise choice.


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