Cisco 10G S-Class vs Non-S-Class Modules: How to Choose?

A wide variety of Cisco 10G SFP+ modules including SFP-10G-SR have earned a broad reputation and popularity over the past years, which make great contributions to 10G Ethernet deployments in diverse networking environments. While, Cisco launched new 10G S-Class modules like SFP-10G-SR-S in December 2014, offering more options for enterprises and data centers. But some people may still get confused by this series of S-Class optics, as no obvious difference can be found through Cisco’s official datasheets. Therefore, here a comparison between Cisco 10G S-Class and non-S-Class modules is provided to help you make better choices.

Cisco 10G S-Class vs Non-S-Class Module Overviews

Cisco has introduced four kinds of 10G S-Class modules, including SFP-10G-SR-S, SFP-10G-LR-S, SFP-10G-ER-S, SFP-10G-ZR-S, which are all named with an “S”. Abandoning some “unnecessary features”, these optics are especially designed for enterprises, data centers and other environments without special requirements for temperature. While non-S-Class optics have more types, such as SFP-10G-SR, SFP-10G-LR, SFP-10G-ER, SFP-10G-ZR etc. Sharing identical specification, Cisco S-Class modules seem to have no differences with non-S-Class modules. The detailed specification of Cisco S-Class modules is shown in the table below.

Module	Wavelength (nm)	Fiber Mode	Interface	Distance	Temperature (℃)	Power Consumption (W)
SFP-10G-SR-S	850	MMF	LC Duplex	300m	0℃-70℃	1
SFP-10G-LR-S	1310	SMF	LC Duplex	10km	0℃-70℃	1
SFP-10G-ER-S	1550	SMF	LC Duplex	40km	0℃-70℃	1.5
SFP-10G-ZR-S	1550	SMF	LC Duplex	80km	0℃-70℃	1.5

Table 1: Cisco 10G S-Class Module Specification

Cisco 10G S-Class vs Non-S-Class Modules: How to Choose?

Cisco S-Class and non-S-Class modules share the same appearance, size, interface, wavelength, power consumption etc. But the so-called “unnecessary features” may still puzzle those who want to have a try. Here, some major differences of these Cisco 10G SFP+ modules are shown for your considerations.

Protocol

Cisco 10G S-Class modules such as SFP-10G-SR-S only support Ethernet protocol. They don’t support FCoE(Fiber Channel over Ethernet), which is a storage protocol that enables fiber channel communications to run directly over Ethernet. While Cisco 10G non-S-Class modules like SFP-10G-SR support three protocols including Ethernet, OTN (Open Transport Network) and WAN-PHY (Wide Area Network-physical layer). In addition, S-Class 10G transceivers aren’t TAA (Trade Agreements Act) certified, but non-S-Class optics are all compliant to TAA.

Temperature

Cisco 10G S-Class modules can only run at COM (Commercial temperature range: 0~70℃/32~158°F), which will limit the applications beyond this range. However, non-S-Class modules can be used within EXT (Extended temperature range: -5~85℃/23~185°F), IND (Industrial temperature range: -40~85℃/-40~185°F) and COM. For example, SFP-10G-BX 1270nm-TX/1330nm-RX and SFP-10G-BX 1330nm-TX/1270nm-RX can both work in -40~85℃, which are suitable for outdoor deployments or harsh environments such as industries, mines.

Figure 1: FS 10G SFP+ Modules

Transmission Distance

According to Cisco, 10G S-Class modules are more suitable for shorter transmission distance applications compared with non-S-Class modules, such as connections within racks and across adjacent racks in data centers. For this reason, if you don’t need any special long distance, S-Class modules should just be fine for you.

Application

Cisco 10G S-Class transceivers are especially designed for enterprise and data center 10G and 40G applications. They are available only in the most common reaches needed in these environments. While non-S-Class modules are suitable for cases such as non-temperature controlled environments, e.g. rugged/industrial (RGD). Moreover, this type optics are also common solutions in home, enterprises and data centers, which shows a wider application than S-Class optics.

Price

Due to the abandonment of some unnecessary features, 10G S-Class modules are cheaper than non-S-Class ones. Actually, the low price is the main selling point, which attracts many users who are infatuated with Cisco optics. So to speak, 10G S-Class transceivers can be a affordable alternative to non-S-Class ones in enterprises and data centers.

Cisco 10G S-Class vs Non-S-Class Modules: Are They Compatible?

Adding Cisco S-Class optics offers more choices, but some people may wonder “Is Cisco 10G S-Class modules compatible with non-S-Class modules?” Here we take SFP-10G-LR-S and X2-10GB-LR for example.

Cisco 10G SFP+	Wavelength (nm)	Cable Type	Core Size (Microns)	Modal Bandwidth (MHz/km)	Cable Distance
SFP-10G-LR-S	1310	SMF	G.652	-	10km
X2-10GB-LR	1310	SMF	G.652	-	10km

Table 2: SFP-10G-LR-S and X2-10GB-LR Specification

From the above table, it is found that these two types of modules share the same data rate, wavelength and transmission distance, laying the foundation for their interconnection. Moreover, Cisco’s data sheets have demonstrated some important features which can further prove the good compatibility.

Cisco 10G SFP+	Features
SFP-10G-LR-S	Supports Cisco quality identification (ID) feature that enables a Cisco platform to identify optics supported by Cisco technology
	Has optical interoperability with 10GBASE XENPAK, 10GBASE X2 and 10GBASE XFP interfaces on the same link
X2-10GB-LR	Supports the Cisco quality identification (ID) feature that enables a Cisco switch or router to identify whether the module is certified and tested by Cisco
	Has optical interoperability with respective 10GBASE Xenpak, 10GBASE XFP and 10GBASE SFP+ modules on the same link

Table 3: SFP-10G-LR-S and X2-10GB-LR Features

From the above all, it is verified that Cisco 10G S-Class modules are well compatible with non-S-Class modules. They shall work fine together.

Conclusion

Cisco 10G S-Class modules share identical specification with non-S-Class modules, but there still are some minor differences. S-Class optics only support Ethernet protocol, lower temperature tolerance and shorter transmission distance. But the most attractive factor is its lower price, and the compatibility is no problem. In a nutshell, Cisco 10G S-Class modules serve as a low-cost solution, but nowadays third-party 10G transceivers become more cost-effective choices with the high maturity of 10G transceiver technologies. These third-party Cisco compatible 10G non-S-Class modules can be much cheaper but also provide the same high performance, which should be ideal for your applications.

If you are a loyal Cisco user, these 10G S-Class transceivers are ideal choices for you in the most common reaches needed in enterprise and data center applications.