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Choosing the correct optical transceiver for a Cisco Catalyst 9300 is not simply a matter of selecting an SFP with the right speed. The correct solution depends on the exact switch model, installed uplink module, Ethernet speed, fiber type, transmission distance and optical interface.
For example, a network using a C9300-NM-4G uplink module has very different optical requirements from one equipped with a C9300-NM-2Y or C9300-NM-2Q. This guide explains how to choose suitable 1G SFP, 10G SFP+, 25G SFP28 and 40G QSFP+ transceivers for Cisco Catalyst 9300 deployments.
What Is the Cisco Catalyst 9300 Series?
The Cisco Catalyst 9300 Series is a stackable enterprise access-switching platform designed for campus and enterprise networks. Depending on the model and configuration, Catalyst 9300 switches can provide access connectivity for computers, wireless access points, IP phones, IoT devices, servers and other network equipment.
One important feature of standard C9300 models is their use of optional uplink network modules. Instead of having only one fixed uplink configuration, organizations can select different network modules depending on the bandwidth required.
Cisco Catalyst 9300 Network Modules Explained
Before choosing an SFP, first identify the installed network module. This is one of the most important compatibility checks.
| Network Module | Ports | Supported Speed | Typical Transceiver |
|---|---|---|---|
| C9300-NM-4G | 4 | 1G | SFP |
| C9300-NM-8X | 8 | 1G / 10G | SFP / SFP+ |
| C9300-NM-2Y | 2 | 1G / 10G / 25G | SFP / SFP+ / SFP28 |
| C9300-NM-2Q | 2 | 40G | QSFP+ |
| C9300-NM-4M | 4 | Multigigabit | Copper |
C9300-NM-4G
The C9300-NM-4G contains four 1 Gigabit Ethernet SFP slots and is suitable when the network only requires Gigabit optical uplinks.
C9300-NM-8X
The C9300-NM-8X provides eight 10G/1G uplink interfaces, making it one of the most flexible options for networks requiring multiple 1G or 10G optical links.
C9300-NM-2Y
The C9300-NM-2Y provides two 25G/10G/1G interfaces. It is useful when an enterprise has outgrown 10G uplinks but does not yet require 40G.
C9300-NM-2Q
The C9300-NM-2Q provides two 40 Gigabit Ethernet QSFP+ interfaces for higher-capacity aggregation and uplink applications.
1G SFP Options for Cisco Catalyst 9300
For Gigabit Ethernet links, two frequently encountered Cisco optical transceivers are GLC-SX-MMD and GLC-LH-SMD.
| Module | Speed | Fiber | Wavelength | Typical Reach | Connector |
|---|---|---|---|---|---|
| GLC-SX-MMD | 1G | MMF | 850 nm | Up to ~550 m* | LC |
| GLC-LH-SMD | 1G | SMF / supported MMF | ~1310 nm | Up to 10 km on SMF | LC |
*Reach depends on fiber type and the exact platform specification.
10G SFP+ Modules for Cisco Catalyst 9300
For many modern Catalyst 9300 deployments, 10 Gigabit Ethernet is one of the most practical uplink speeds. A C9300 equipped with C9300-NM-8X provides eight 10G/1G uplink interfaces.
Cisco SFP-10G-SR
| Data Rate | 10 Gbps |
|---|---|
| Standard | 10GBASE-SR |
| Wavelength | 850 nm |
| Fiber | Multimode Fiber |
| Connector | Duplex LC |
| OM3 Reach | Up to 300 m |
| OM4 Reach | Up to 400 m |
SFP-10G-SR is commonly used for data centers, equipment rooms, same-building connections and other short multimode fiber links.
Cisco SFP-10G-LR
| Data Rate | 10 Gbps |
|---|---|
| Standard | 10GBASE-LR |
| Wavelength | 1310 nm |
| Fiber | Single-Mode Fiber |
| Connector | Duplex LC |
| Nominal Reach | Up to 10 km |
SFP-10G-LR is a common choice for campus networks, building-to-building connections and longer enterprise fiber runs.
SFP-10G-SR vs SFP-10G-LR
The most important difference is not speed—both operate at 10 Gbps. The major differences are fiber type, wavelength and transmission distance.
| Feature | SFP-10G-SR | SFP-10G-LR |
|---|---|---|
| Speed | 10G | 10G |
| Wavelength | 850 nm | 1310 nm |
| Fiber | MMF | SMF |
| Typical Maximum | 300 m OM3 / 400 m OM4 | 10 km |
| Connector | LC duplex | LC duplex |
| Typical Use | Data center / building | Campus / long-distance |
Selection tip: Check the installed fiber type before ordering. A 10G requirement alone does not tell you whether SR or LR is correct.
Catalyst 9300 SFP Compatibility Overview
| Speed | Form Factor | Example Cisco Optics | Typical Use |
|---|---|---|---|
| 1G | SFP | GLC-SX-MMD / GLC-LH-SMD | Access and campus links |
| 10G | SFP+ | SFP-10G-SR / SFP-10G-LR | Data center and campus uplinks |
| 25G | SFP28 | SFP-25G-SR-S | Higher-capacity enterprise uplinks |
| 40G | QSFP+ | QSFP-40G-SR4 | Aggregation and backbone |
25G SFP28 on Cisco Catalyst 9300
The standard Catalyst 9300 can support 25G through the C9300-NM-2Y network module. One common Cisco short-reach option is SFP-25G-SR-S.
| Data Rate | 25 Gbps |
|---|---|
| Fiber | Multimode Fiber |
| Wavelength | 850 nm |
| Connector | Duplex LC |
| OM3 Reach | Up to 70 m |
| OM4 Reach | Up to 100 m |
| Host Requirement | RS-FEC required for SFP-25G-SR-S |
40G QSFP+ on Cisco Catalyst 9300
For higher aggregation bandwidth, C9300-NM-2Q provides two 40G QSFP+ interfaces. A well-known short-reach option is QSFP-40G-SR4.
| Data Rate | 40 Gbps |
|---|---|
| Fiber | Multimode Fiber |
| Wavelength | ~850 nm |
| Connector | MPO-12 / MTP |
| OM3 Reach | Up to 100 m |
| OM4/OM5 Reach | Up to 150 m |
25G SFP28 vs 40G QSFP+: Which Is Better?
Neither is automatically better. The correct choice depends on the installed network module, existing cabling and bandwidth requirements.
Cisco Catalyst 9300 Optical Module Quick Comparison
| Module | Speed | Fiber | Wavelength | Typical Reach | Connector |
|---|---|---|---|---|---|
| GLC-SX-MMD | 1G | MMF | 850 nm | Up to 550 m* | LC |
| GLC-LH-SMD | 1G | SMF/MMF | ~1310 nm | Up to 10 km SMF | LC |
| SFP-10G-SR | 10G | MMF | 850 nm | 300 m OM3 / 400 m OM4 | LC |
| SFP-10G-LR | 10G | SMF | 1310 nm | 10 km | LC |
| SFP-25G-SR-S | 25G | MMF | 850 nm | 70 m OM3 / 100 m OM4 | LC |
| SFP-10/25G-LR-S | 25G | SMF | LR class | Up to 10 km | LC |
| QSFP-40G-SR4 | 40G | MMF | 850 nm | 100 m OM3 / 150 m OM4/5 | MPO-12 |
How to Choose the Right SFP for Cisco Catalyst 9300
- Check the exact Catalyst 9300 switch model.
- Confirm the installed network module.
- Select the required Ethernet speed.
- Identify single-mode or multimode fiber.
- Verify the required transmission distance.
Example: Selecting a 10G Module
Suppose the customer has a C9300-48P with C9300-NM-8X, needs 10G, uses single-mode fiber, and has a 5 km link. An LR-class optic such as SFP-10G-LR would normally be evaluated rather than an SR optic.
Original Cisco vs Third-Party Compatible Optical Transceivers
Organizations may source genuine Cisco-branded optics through Cisco or authorized channels, or use third-party optical transceivers designed for interoperability with specific Cisco platforms. A module should not be considered compatible simply because it physically fits the port. Compatibility evaluation should consider switch model, network module, port speed, software environment, fiber type, wavelength, distance, connector and transceiver coding.
Frequently Asked Questions
What SFP modules are compatible with Cisco Catalyst 9300?
Compatibility depends on the exact switch and uplink module. Standard C9300 configurations cover 1G SFP, 10G SFP+, 25G SFP28 and 40G QSFP+ uplink options.
Does Cisco Catalyst 9300 support SFP-10G-LR?
Supported C9300 configurations using a 10G uplink module such as C9300-NM-8X can use 10G SFP+ optics. SFP-10G-LR is designed for 10G single-mode links up to approximately 10 km.
Does C9300-NM-8X support 1G SFP?
Yes. Cisco documents the C9300-NM-8X as supporting both 1G and 10G configurations with appropriate SFP/SFP+ modules.
Does Catalyst 9300 support 25G SFP28?
Yes, with supported hardware such as the C9300-NM-2Y, which provides 25G/10G/1G uplink capability.
Does Catalyst 9300 support 40G QSFP+?
Yes. The C9300-NM-2Q provides two 40G QSFP+ uplink interfaces.
Conclusion
Choosing the correct transceiver for a Cisco Catalyst 9300 becomes much easier when the selection process is done in the right order: switch model → network module → required speed → fiber type → transmission distance.
GLC-SX-MMD is suitable for many short 1G multimode links; GLC-LH-SMD for longer 1G links; SFP-10G-SR for short 10G multimode links; SFP-10G-LR for 10G single-mode links up to about 10 km; SFP-25G-SR-S for short 25G links; and QSFP-40G-SR4 for high-capacity 40G multimode connectivity.