Which SFP / transceiver works with a Cisco Catalyst 9300?
The Catalyst 9300 is a fixed-configuration access switch, but its uplinks are modular: which SFP, SFP+, SFP28, or QSFP optic you can run depends entirely on the network module seated in the uplink bay. Below is the module-by-module compatibility, the common Cisco optics by distance, and how to handle third-party transceivers.
Which SFP works with a Cisco Catalyst 9300? It depends on the installed uplink network module. The C9300-NM-8X takes 10G SFP+ and 1G SFP optics (SFP-10G-SR, GLC-TE); the C9300-NM-4G is 1G SFP only; the C9300-NM-2Y adds 25G SFP28; and the C9300-NM-2Q uses 40G QSFP+. Optics live in the module, not the fixed downlink ports.
The Catalyst 9300 is a fixed-configuration access switch, but its uplinks are modular: which SFP, SFP+, SFP28, or QSFP optic you can run depends entirely on the network module seated in the uplink bay. Below is the module-by-module compatibility, the common Cisco optics by distance, and how to handle third-party transceivers.
The 9300 uplink model: fixed downlinks, one swappable network module
A Catalyst 9300 ships as a 24- or 48-port fixed-configuration access switch. The front-panel downlink ports are set by the SKU — 1G copper (RJ-45), Multigigabit copper, or 1G SFP — and are not user-changeable. The optics question lives almost entirely in the rear uplink network module bay: a single hot-swappable slot that accepts one C9300-NM (Catalyst 9300) or C9300X-NM (Catalyst 9300X) module.
So "which SFP works with a 9300" is really "which module is installed, and what does that module's cage accept." Swapping the module changes your uplink speed and media without replacing the switch. Browse chassis on the Catalyst 9300 48-port PoE product page and pluggables in the networking catalog.
One caveat on the fixed ports: copper and mGig downlink SKUs use RJ-45 patch cables, not pluggable optics. Only the SFP-downlink SKUs (for example C9300-24S / C9300-48S) accept 1G SFP optics in the front ports.
Catalyst 9300 network module to optic compatibility matrix
Each module dictates the form factor and the speeds its cages accept. SFP+ and SFP28 cages are dual/triple-rate, which is why a 10G or 25G module still takes a 1G GLC-TE.
| Network module | Ports & cage | Speeds accepted | Example optics / cables |
|---|---|---|---|
| C9300-NM-4G | 4 × SFP | 1G only | GLC-TE, GLC-SX-MMD, GLC-LH-SMD (no SFP+) |
| C9300-NM-8X | 8 × SFP+ | 1G / 10G | SFP-10G-SR, SFP-10G-LR, SFP-10G-T-S, SFP-H10GB-CU DAC, GLC-TE (1G) |
| C9300-NM-2Y | 2 × SFP28 | 1G / 10G / 25G | SFP-25G-SR-S, SFP-H25G-CU DAC, SFP-10G-SR, GLC-TE |
| C9300-NM-2Q | 2 × QSFP+ | 40G | QSFP-40G-SR4, QSFP-40G-LR4, QSFP-H40G-CU DAC |
| C9300-NM-4M | 4 × mGig RJ-45 | 100M/1/2.5/5/10G copper | None — Cat6a patch, ≤100 m |
| C9300X-NM-8Y | 8 × SFP28 | 1G / 10G / 25G | SFP-25G-SR-S, SFP-10G-SR/LR, DAC |
| C9300X-NM-8M | 8 × mGig RJ-45 | 100M–10G copper | None — Cat6a patch |
| C9300X-NM-2C | 2 × QSFP28 | 40G / 100G | QSFP-100G-SR4, QSFP-40G-SR4, QSFP-100G-CU DAC |
| C9300X-NM-4C | 4 × QSFP28 | 40G / 100G | QSFP-100G-SR4/LR4, 40G QSFP+, DAC |
QSFP+ (40G) and QSFP28 (100G) cages also support 4×10G / 4×25G breakout to SFP+/SFP28 with the correct breakout cable, and the dual-rate 2C/4C cages fall back to 40G. 100G is a Catalyst 9300X feature only — the base 9300 tops out at 40G via the C9300-NM-2Q. Always confirm the exact supported-optics list against the IOS XE release notes for your running software version.
Common Cisco optics for the 9300, by distance and media
Pick the optic by the cage form factor first, then by reach and fiber type. These are the parts most 9300 uplinks use.
| Optic / cable | Standard | Media & connector | Wavelength | Max reach |
|---|---|---|---|---|
| GLC-TE | 1000BASE-T | Cat5e, RJ-45 | — | 100 m |
| SFP-H10GB-CU | 10G Twinax (DAC) | Fixed copper | — | 1–5 m passive |
| SFP-10G-T-S | 10GBASE-T | Cat6a, RJ-45 | — | 30 m |
| SFP-10G-SR | 10GBASE-SR | OM3/OM4 MMF, LC | 850 nm | 300 m OM3 / 400 m OM4 |
| SFP-10G-LR | 10GBASE-LR | SMF, LC duplex | 1310 nm | 10 km |
| QSFP-40G-SR4 | 40GBASE-SR4 | OM3/OM4 MMF, MPO-12 | 850 nm | 100 m OM3 / 150 m OM4 |
| QSFP-40G-LR4 | 40GBASE-LR4 | SMF, LC duplex | 1310 nm (4λ) | 10 km |
The two multimode workhorses — SFP-10G-SR for 10G uplinks and QSFP-40G-SR4 for 40G — cover the vast majority of in-building 9300 deployments; step up to LR/LR4 single-mode only when you cross the 300–400 m multimode ceiling.
Multimode, single-mode, or DAC: choosing the media
Three media classes cover every 9300 uplink. Match the run length and the switch's location to the cheapest option that reaches:
- DAC / Twinax (SFP-H10GB-CU, SFP-H25G-CU): same-rack or adjacent-rack runs, typically ≤5 m passive. Cheapest, lowest power, no separate optic to source — ideal for switch-to-server or stacking-adjacent uplinks in a top-of-rack build.
- Multimode (SR / SR4): within a building or across a patch-panel plant, up to 300–400 m on OM3/OM4. Lower optic cost than single-mode but distance-limited; uses LC duplex (SR) or MPO-12 (SR4).
- Single-mode (LR / LR4): campus and building-to-building runs, 10 km and beyond on LC duplex. Optics cost more, but the fiber is future-proof for higher speeds and long reach.
Rule of thumb: DAC in the rack, multimode in the building, single-mode between buildings. Verify the exact fiber grade and connector before ordering — an SR4 needs MPO trunk cabling, not the duplex LC an SR uses.
"Unsupported transceiver" errors and coded-for-Cisco optics
Cisco optics carry a coded EEPROM (serial and security data) that the 9300 reads on insertion. A non-coded or wrongly coded optic throws %PHY-4-UNSUPPORTED_TRANSCEIVER or a %GBIC_SECURITY error, and the port can drop into err-disabled state.
You can force the switch to accept third-party optics with two global-config commands (supported since IOS 12.2(25)SE):
service unsupported-transceiver— accepts non-Cisco pluggables and prints a warning that Cisco may withhold TAC support.no errdisable detect cause gbic-invalid— stops the port from being disabled on an "invalid" pluggable.
The trade-off: Cisco TAC will not troubleshoot links running unsupported optics, and the module may show as Unknown in show interface transceiver. In practice, reputable refurbished and third-party optics are coded to the exact Cisco part they emulate, so they present as genuine and need no override — the errors above usually mean a mis-coded optic or one coded for a different platform. Confirm coding and platform support with our SFP transceiver compatibility guide and the compatibility tool before you deploy.
Related reading: Buying refurbished network switches, the SFP transceiver compatibility guide, and the optics compatibility tool.
Frequently asked questions
Can I use 1G SFP optics in the C9300-NM-8X 10G module?
Yes. The SFP+ cages on the C9300-NM-8X are dual-rate and accept 1G SFP optics such as GLC-TE and GLC-SX-MMD alongside 10G SFP+. The reverse is not true: the C9300-NM-4G is a 1G-only module and will not take SFP+.
Does the Catalyst 9300 support third-party (non-Cisco) SFPs?
Technically yes. Enter service unsupported-transceiver and no errdisable detect cause gbic-invalid in global config to accept them, but Cisco TAC will not support links using non-Cisco optics. Most refurbished optics are coded to the equivalent Cisco part and work without the override.
Does the C9300-NM-4G support 10G SFP+?
No. The C9300-NM-4G has four 1G SFP slots and supports 1G optics only. For 10G uplinks you need the C9300-NM-8X (8×SFP+), and for 25G the C9300-NM-2Y (2×SFP28).
Can a Catalyst 9300 do 40G or 100G uplinks?
40G yes, via the C9300-NM-2Q (2×QSFP+) using optics like the QSFP-40G-SR4. 100G requires a Catalyst 9300X chassis with a C9300X-NM-2C or -4C QSFP28 module; the base 9300 tops out at 40G.
What is the difference between SFP-10G-SR and SFP-10G-LR on a 9300?
SFP-10G-SR is multimode (850 nm, OM3/OM4), reaching 300–400 m for in-building links. SFP-10G-LR is single-mode (1310 nm) and reaches 10 km for campus or building-to-building runs. Both fit any SFP+ cage such as the C9300-NM-8X.
Do the fixed downlink ports on a 9300 take SFP optics?
Only on the SFP-downlink SKUs (C9300-24S / C9300-48S), which accept 1G SFP in the front ports. Copper and Multigigabit SKUs use RJ-45 patch cables in the downlinks; all fiber/DAC uplink optics go in the rear network module.