Cisco SFP transceivers connect switches, routers and servers over fiber or copper. The right module depends on speed, fiber type and distance, so one wrong detail can leave a link dark.
This guide covers the 1G, 10G, 25G and 100G optics buyers ask for most. It also explains DOM, S-Class and RS-FEC, so you can order with confidence.
How Cisco SFP transceivers are named
Cisco part numbers tell you a lot once you know the pattern. The GLC parts in this guide are 1G SFP modules, while SFP-10G parts are 10G SFP+ modules. Similarly, SFP-25G parts are SFP28, and QSFP-100G parts are QSFP28.
Suffixes matter too. For example, -MMD and -SMD mean the module supports DOM, which reports light levels and temperature. Meanwhile, -S marks S-Class optics, which do not support FCoE.
1G Cisco SFP transceivers
Gigabit optics still fill many access switch uplinks and router ports. Three models cover most needs.
GLC-TE copper SFP
The GLC-TE is a 1000BASE-T copper SFP with an RJ-45 port. It runs up to 100m over Category 5 cable. So it suits short copper runs from an SFP port.
GLC-SX-MMD for multimode fiber
The GLC-SX-MMD is a 1000BASE-SX module at 850nm with DOM. It reaches 1000m on OM3, OM4 or OM5 fiber, 550m on OM2 and 275m on OM1. As a result, it fits most links inside a building.
GLC-LH-SMD for longer links
The GLC-LH-SMD is a 1000BASE-LX/LH module at 1310nm with DOM. It runs up to 10km on single mode fiber, or 550m on multimode. Because of that, it handles links between buildings on a campus.
10G Cisco SFP+ transceivers
10G is the standard uplink speed for most closets today. So these three modules come up on almost every quote.
SFP-10G-SR-S
The SFP-10G-SR-S is a 10GBASE-SR module at 850nm with dual LC connectors. It reaches 300m on OM3 and 400m on OM4. However, as an S-Class optic, it does not support FCoE.
SFP-10G-LR
The SFP-10G-LR uses 1310nm single mode fiber and reaches up to 10km. So it is the usual pick for 10G links between buildings with single mode cabling.
SFP-10G-T-X
The SFP-10G-T-X turns an SFP+ port into a 10GBASE-T copper port. It runs up to 30m at 10G on CAT6A, and up to 100m at 100M or 1G. Therefore, plan for short runs if you need full 10G speed.
25G and 100G Cisco SFP transceivers
Data center switches such as the Nexus 9000 family use 25G server ports and 100G uplinks. These two modules are common choices.
SFP-25G-SR-S
The SFP-25G-SR-S is a 25GBASE-SR module at 850nm on multimode fiber with dual LC. It reaches 70m on OM3 and 100m on OM4. Also, the host port must have RS-FEC on, so check the switch settings before you blame the optic.
QSFP-100G-SR1.2
The QSFP-100G-SR1.2 is a 100G BiDi module that uses 855nm and 908nm over duplex LC multimode fiber. It reaches 70m on OM3, 100m on OM4 and 150m on OM5. In fact, it lets you reuse duplex fiber for 100G instead of pulling new cable.
How to choose Cisco SFP transceivers
A short checklist prevents most optics mistakes. So run through it before you order.
- Check the port type first, whether SFP, SFP+, SFP28 or QSFP28.
- Then confirm the fiber, either multimode (OM1 to OM5) or single mode.
- Measure the distance, and leave some margin.
- Match both ends, since an SR optic will not link with an LR optic.
- Avoid S-Class optics for FCoE links.
Also check that your switch software supports the module. Cisco publishes compatibility tables for its optics, so a quick check saves a return.
Where these optics fit in a Cisco network
Most optics orders follow the switch. For example, the 10G uplinks on a Catalyst 9200L 4X model take SFP+ modules such as the SFP-10G-SR-S or SFP-10G-LR. Similarly, the four SFP uplinks on a Catalyst 2960-X take 1G modules such as the GLC-SX-MMD.
Meanwhile, the 25G ports on a Catalyst 9500 or Nexus 93180YC switch take SFP28 modules. Their 100G uplinks then take QSFP28 modules such as the QSFP-100G-SR1.2. So list the switch model with each optic on your quote, because it helps us confirm the match.
New and used Cisco SFP transceivers
Silverback supplies genuine Cisco optics, new and used, tested before they ship. Used optics are a smart way to fill a new switch or keep spares on hand. In addition, testing confirms the module works before it reaches you.
For a wider look at fiber gear, see our fiber optic products. Also compare both options in refurbished vs new hardware.
Cisco SFP transceivers part numbers we supply
Silverback supplies every part below, new and used, tested before it ships.
| Part number | Product | Notes |
|---|---|---|
| GLC-TE | 1000BASE-T copper SFP | RJ-45, up to 100m on Category 5 |
| GLC-SX-MMD | 1000BASE-SX SFP with DOM | 850nm multimode, up to 1000m on OM3/OM4/OM5 |
| GLC-LH-SMD | 1000BASE-LX/LH SFP with DOM | 1310nm, 10km single mode or 550m multimode |
| SFP-10G-SR-S | 10GBASE-SR SFP+ S-Class | 850nm multimode, 300m OM3, 400m OM4, no FCoE |
| SFP-10G-LR | 10GBASE-LR SFP+ | 1310nm single mode, dual LC, up to 10km |
| SFP-10G-T-X | 10GBASE-T copper SFP+ | 30m at 10G on CAT6A, 100m at 100M/1G |
| SFP-25G-SR-S | 25GBASE-SR SFP28 S-Class | 850nm multimode, 70m OM3, 100m OM4, needs RS-FEC |
| QSFP-100G-SR1.2 | 100G SR1.2 BiDi QSFP28 | Duplex LC multimode, 70m OM3, 100m OM4, 150m OM5 |
Send us the part number and get pricing and lead time within one business day. You can also request a quote or browse our inventory. Full specs are on the Cisco 10G SFP+ data sheet and related Cisco pages.
For the wider range of switches and routers, see our Cisco buyer's guide.
Frequently Asked Questions
What does S-Class mean on Cisco optics?
The -S suffix marks S-Class optics, such as the SFP-10G-SR-S. S-Class optics do not support FCoE.
What does DOM mean?
DOM stands for digital optical monitoring. It reports light levels and temperature, and modules such as the GLC-SX-MMD and GLC-LH-SMD support it.
How far does the SFP-10G-LR reach?
It reaches up to 10km over single mode fiber at 1310nm.
Why will my 25G SR link not come up?
The SFP-25G-SR-S needs RS-FEC turned on for the host port. So check the switch port settings first.
Can the GLC-TE run at 10G?
No. The GLC-TE is a 1G module. For 10G copper, use the SFP-10G-T-X, which runs up to 30m on CAT6A.
Get a quote for Cisco SFP transceivers
Send your optics list with quantities, speeds and fiber types. We reply with pricing and lead time within one business day.
Call (888) 391-5211 or request a quote online. Also tell us whether you want new or used condition.
