What are the SFP-10G-SR and SFP-10G-LR?

In simple terms, the SFP-10G-SR/LR is a very common type of optical module. Cisco, Huawei and other large manufacturers have this kind of production, mainly used in switches and routers, we can analyze it from the three aspects.

SFP (Small Form-factor Pluggable) refers to a small module that can be hot-pluggable. It can be regarded as an upgraded version of GBIC. It only sizes as the thumb and can greatly increase the port density. The SFP complies with the IEEE802.3, SFF-8472 protocol and can use digital diagnostics through I2C.
10G stands for its maximum transmission rate of 10.3 Gbps. It is suitable for 10 Gigabit Ethernet. 10G optical networks have become popular in telecommunication networks. 10G switches are also being used by more and more people.

SR and LR represent the transmission distance of the optical module. SR, LR, LRM, ER and ZR are more common in the 10G IEEE standard. The transmission distance they represent is from short to long. You can check it by the following table.

10G IEEE standard	Transmission Distance
10GBASE-SR	300m or 400m
10GBASE-LR	10km
10GBASE-LRM	200m
10GBASE-ER	40km
10GBASE-ZR	80km

 

Comparison of appearance

Let us first look at the appearance of the SFP-10G-LR-S optical module and the SFP-10G-SR-S optical module. They are packaged in the form of SFP+ and can be plugged into the SFP+ port of the switch and are also hot-pluggable. The overall size is also the same. Because of different manufacturers, there are differences in the label position and interface design of the two optical modules, but the components are the same and there is no difference between them.

Name	SFP-10G-SR	SFP-10G-LR
Package type	SFP+	SFP+
Rate	10 Gbps	10 Gbps
Wavelength	850nm	1310nm
Distance（max）	300m	10km
Interface	LC duplex	LC duplex
Laser type	VCSEL 850nm	DFB 1310nm
Fiber optic type	MMF	SMF
DOM	YES	YES
Transmitted light power	-6～-1dBm	-8.2～0.5dBm
Received sensibility	< -11.1dBm	< -14.4dBm
Commercial temperature	0～ 70°C (32 ～ 158°F)	0～ 70°C (32 ～ 158°F)
Features	Maximum transmission rate 10.3Gbps 850 nm VCESL Laser Typical transmission distance 300 meters (OM3 multimode fiber) 3.3V single voltage, TTL logic interface Dual LC interface, hot-pluggable	Maximum transmission rate 10.3Gbps 1310 nm DFB-LD Laser Typical transmission distance 10 kilometers 3.3V single voltage, TTL logic interface Dual LC interface, hot-pluggable
Application range	Only used for short distance connections	Only used for long distance connections

 

SFP-10G-SR and SFP-10G-SR-S are both transceiver modules commonly used in networking applications. Here's the difference between the two:

1. SFP-10G-SR: This is a standard short-range multi-mode transceiver that operates at a wavelength of 850nm. It supports Ethernet speeds of up to 10Gbps and can transmit data over distances of up to 300 meters (depending on the quality of the fiber and networking equipment).

2. SFP-10G-SR-S: The "-S" in SFP-10G-SR-S stands for "settlement-free" or "simplified." This transceiver module is functionally equivalent to the SFP-10G-SR, but it is offered at a lower cost. The "S" variant is typically used for high-volume deployments where price is a significant factor.

In terms of performance and compatibility, both modules are compatible with the same networking equipment and can achieve the same data transfer rates over similar distances. The main difference lies in their pricing and marketing strategy.

According to Cisco, S-class optics are intended for enterprise and data center 10G and 40G applications This new set of optics does not display several unnecessary features for these applications, bringing about a more attractive price. That explains why SFP-10G-SR-S price is lower than SFP-10G-SR price.

Except the price, there are some other differences. SFP-10G-SR-S optics aren’t TAA certified. However, the non-S-class optics such as SFP-10G-SR are all compliant to TAA. SFP-10G-SR-S optics only have COM (Commercial temperature range: 0~70℃). However, the temperature range of SFP-10G-SR can be EXT (Extended temperature range: -5~85℃), IND (Industrial temperature range: -40~85℃) and Storage temperature range (-40~85℃). In terms of protocols, SFP-10G-SR-S optics use Ethernet only, they cannot use OTN (Optical Transport Network) or WAN-PHY (Wide Area Network Physics). Furthermore, SFP-10G-SR-S optics just have 10G and 40G applications so far which is specified for 10G and 40G enterprise and data center. Thus, if you don’t need any special features like extra tolerance for temperature, S-Class optics can save you a considerable amount of money.

Will You Buy SFP-10G-SR or SFP-10G-SR-S?

However, with the increasing development of 3rd-party compatible optics market, Cisco S-class optics are as popular as Cisco expected. For instance, you may prefer to buy a Cisco SFP-10G-SR compatible optics with 18 dollars in Fiberstore rather than about 500 dollars of Cisco SFP-10G-SR-S optics. Because you can enjoy the same functions and performance the Cisco SFP-10G-SR have and just at an incredible price. Of cause, if you are a loyal Cisco user, S-class optics are an ideal choice for you on the most common reaches needed in enterprise and data center applications.