Cisco · Optical Transceivers & SFP
Cisco GLC-SX-MMD — 1000BASE-SX SFP transceiver
- Part number
- GLC-SX-MMD
- Manufacturer
- Cisco
- Standard
- 1000BASE-SX
The GLC-SX-MMD is Cisco's standard gigabit short-reach optic: a 1000BASE-SX SFP for multimode fibre at 850 nm, with digital optical monitoring. It is the most frequently specified Cisco transceiver in enterprise and campus networks, and the module most often requested when a switch uplink or server link runs over multimode fibre inside a building.
Specifications
| Standard | 1000BASE-SX (IEEE 802.3z) |
|---|---|
| Data rate | 1.25 Gbit/s (Gigabit Ethernet) |
| Wavelength | 850 nm |
| Fibre | Multimode; 550 m over 50 µm OM2 |
| Connector | Duplex LC |
| Form factor | SFP, hot-swappable |
| Monitoring | Digital optical monitoring (DOM) |
| Typical platforms | Catalyst, ISR, ASR and Nexus switches and routers with SFP ports |
Source: Cisco 1000BASE SFP transceiver data sheet.
Variants and part-number suffixes
GLC-SX-MMD replaced the earlier GLC-SX-MM. The optical specification is the same; the D indicates digital optical monitoring, which the legacy code lacks. GLC-SX-MM is end-of-sale and now supplied as new surplus or refurbished; GLC-SX-MMD is current and supplied new.
Industrial-temperature variants carry an -RGD suffix (GLC-SX-MM-RGD) and are listed on the Cisco optics page.
Equivalent part numbers from other manufacturers
The same 1000BASE-SX optical class is sold under other manufacturers' part numbers. These are not interchangeable in a Cisco switch, but they identify the matching module for other platforms in the same network.
| Manufacturer | Part number | Note |
|---|---|---|
| Cisco Meraki | MA-SFP-1GB-SX | Meraki MS and MX platforms |
| HPE Aruba | J4858D | Aruba CX and ArubaOS-Switch |
| HPE FlexNetwork | JD118B | Comware switches |
| Juniper | EX-SFP-1GE-SX | EX-series switches |
| MikroTik | S-85DLC05D | RouterBOARD, CCR, CRS |
| Ubiquiti | UF-MM-1G | UniFi and UISP |
| Finisar (Coherent) | FTLF8519P3BNL | Uncoded MSA module |
Equivalent optical class only. Each platform accepts modules coded for it; order the code that matches the switch.
Before you order
Cisco switches check the vendor code written into each module and will reject or flag an unsupported one, so give the switch model and IOS / IOS XE / NX-OS release with the enquiry. State whether you require genuine Cisco or will accept a Cisco-coded compatible module — we quote both as separate lines and never present one as the other. Optics are the most counterfeited category in the secondary market; we source through channels we can verify and state the origin of every module on the quotation.
Equipment condition
New — factory-sealed, supplied through the manufacturer's own channel or a qualified distributor, with full manufacturer warranty.
New surplus — unused factory stock, original packaging where available, sourced from decommissioned projects or distributor inventory. Manufacturer warranty may have lapsed; CRS PLUS warranty applies.
Refurbished / tested — previously deployed equipment, cleaned, firmware-checked and functionally tested against the manufacturer's specification before shipment. CRS PLUS warranty applies.
Condition is confirmed in writing on every quotation before you commit to an order.
Warranty
Warranty terms vary by item, by condition and by the supplier the equipment is sourced from. They are stated in writing on the quotation, per line item, before you commit to an order.
Where equipment is supplied new through the manufacturer's own channel, the manufacturer's warranty applies and is passed to you.
Send us the part numbers you need and we will confirm warranty terms alongside availability, condition, lead time and price.
Questions
Frequently asked questions
Is GLC-SX-MMD the same as GLC-SX-MM?
Same 1000BASE-SX optical specification. GLC-SX-MMD adds digital optical monitoring and is the current part; GLC-SX-MM is the end-of-sale predecessor. Most Cisco platforms accept both.
What reach does GLC-SX-MMD support?
Up to 550 m over 50 µm OM2 multimode fibre, with shorter distances on 62.5 µm fibre. For single-mode fibre or longer links use the GLC-LH-SMD (10 km).
Will a compatible GLC-SX-MMD work in my Catalyst switch?
A correctly Cisco-coded compatible module normally will; an uncoded module is likely to be rejected. We quote genuine and coded-compatible modules as separate lines.
Related pages
Manufacturer names, product names and part numbers are the property of their respective owners and are used here for identification purposes only. CRS PLUS sources these products through its qualified supplier base and holds no distributor, reseller or agency appointment from any manufacturer listed.
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