Tag Archives: 10GBASE-SR

What’s the Difference: 10GBASE-SR vs 1000BASE-SX

As the development of fiber optic network, there appears lots of industry standards for fiber optic transceivers. Although transceivers with different standards may have different features and performance, they sometimes can be used in the same switch port. Thus, many people may get confused by these transceivers. For example, 10GBASE-SR and 1000BASE-SX transceivers can both be inserted into the Cisco Catalyst 2960S-48TD-L switch, but the 10GBASE-SR transceiver may not work fine with the 1000BASE-SX module in another switch. Why? This post will discuss 10GBASE-SR vs 1000BASE-SX and whether 10GBASE-SR transceiver can down-support connect to 1000BASE-SX transceiver.

connect 10GBASE-SR to 1000BASE-SX


As mentioned above, 10GBASE-SR and 1000BASE-SX are two kinds of industry standards for fiber optic transceivers. This part will introduce them in turns.


10GBASE-SR is defined in the IEEE 802.3 Clause 49 standard, specially designed for multi-mode fiber optic medium that uses 850 nm lasers. It has a data transmission rate of up to 10.3125 Gbps and can be used over multiple cabling options. But the transmission distance may differ as the fiber cable changes. For example, when used over OM1 cabling, the 10GBASE-SR has a maximum working distance of 33 meters, as opposed to 82 meters when applied over OM2 cabling. Nowadays, the 10GBASE-SR module usually applied over OM3 and OM4 cablings to give a more structured optical cabling used in large buildings. And the transmission distance respectively are 300m and 400m.


Like 10GBASE-SR, 1000BASE-SX is also an IEEE 802.3z standard for the multi-mode fiber optic cabling. But it has a minimum transmission distance of 220m and a maximum of 550m. Offering 1Gbps data transmission rate, 1000BASE-SX modules are mainly used to connect high-speed hubs, Ethernet switches, and routers together in different wiring closets or buildings using long cabling runs.

Can 10GBASE-SR Transceiver Down-Support Connect to 1000BASE-SX Transceiver?

10GBASE-SR modules are generally referring to 10GBASE-SR SFP+ transceivers, and 1000BASE-SX modules are usually 1000BASE-SX SFP transceivers. And since SFP+ and SFP transceivers share the same size (as shown below), SFP transceivers can often used in most SFP+ ports (For example, almost all SFP+ ports of Cisco switch can accept SFP transceivers). Then can a 10GBASE-SR SFP+ transceiver down-support connect to the 1000BASE-SX SFP transceiver?


10GBASE-SR vs 1000BASE-SX Transceivers

The answer is no. Unlike copper SFP transceivers, 10GBASE-SR SFP+ transceivers do not have such functions as auto-negotiation. In fact, both 10GBASE-SR SFP+ and 1000BASE-SX SFP transceivers can only run at the rated speed fixed by the electro-optical conversion ASIC built into the transceiver hardware. That’s to say, 10GBASE-SR SFP+ transceivers can only run at 10Gbps and 1000BASE-SX SFP transceivers run at 1Gbps. So there is no such fiber link that one end does 1G while the other end does 10G.

10GBASE-SR vs 1000BASE-SX: Have You Known the Differences?

To conclude, although 10GBASE-SR and 1000BASE-SX share something in common, they are totally different Ethernet standards for transceivers. 10GBASE-SR SFP+ transceivers mainly work in 10G links, while 1000BASE-SX transceivers can only run at 1Gbps even though in the SFP+ slot. Thus, it will not work out to connect a 10GBASE-SR SFP+ transceiver with a 1000BASE-SX SFP transceiver.

Related Article: What Is SFP Connector, SFP+ Connector and SFP28 Connector?
Related Article: Choose 10GBASE-T Copper Over SFP+ for 10G Ethernet

Four Families OF 10 Gigabit Ethernet

The IEEE 10 Gb/s standard was first specified in the 802.3ae supplement, which was adopted in 2002. This supplement defined the basic 10 Gigabit system and a set of fiber optic media standards. Subsequent 10 Gb/s supplements have added copper media types, including a short-range copper connection based on twinaxial cable and a twisted-pair media system capable of reaching 300 m.

There are four sets of physical layer(PHY) specification, also called”families”in the standard. which are grouped by their use of the same signal encoding techniques and other elements.

Based on 64B/66B signal encoding, this includes the following optical fiber media
systems: 10GBASE-SR, 10GBASE-LR, 10GBASE-ER, and 10GBASE-LRM.

Based on 8B/10B signal encoding, including both fiber optic (10GBASE-LX4) and
copper (10GBASE-CX4) media systems.

Based on 64B/65B encoding, supporting transmission over twisted-pair cabling.

Based on 64B/66B encoding that is encapsulated and transmitted over an OC-192
SONET optical fiber system. This includes the 10GBASE-SW, 10GBASE-LW, and
10GBASE-EW media specifications.

10 Gigabit Ethernet LAN PHYs include five media systems:


Each of the LAN PHYs was specified to provide a media system for a specific set of uses. The short-reach systems are intended for connections between switches in a building or a data center, and from switch ports to server interfaces. The long-reach systems, intended for backbone links on campus and enterprise networks, use more expensive. Single-mode laser-based optics to drive 10 Gigabit signals over longer distances, with
ranges from 10 km for the LR system up to 30–40 km for the ER.

The most used fiber Media Components in 10 Gigabit Ethernet:

Multimode fiber optic cable for short-reach applications.
Single-mode fiber optic cables for long-reach applications.
Mode conditioning patch cable for FDDI grade multimode fiber and OM1 or OM2 cables, up to 220m.
Transceiver: The most popular current form is the SFP+ Module.

Fiber-optic-tutorial.com will offer more information about Gigabit Ethernet. You can also buy fiber media components from Fiberstroe.