Transceiver Selection Guide: SFP+ vs QSFP28 vs QSFP-DD
Compare SFP+, QSFP28, and QSFP-DD transceivers including data rates, reach, power consumption, and compatibility. Find the right module for your network architecture.
Introduction
Choosing the right transceiver is critical for network performance, cost efficiency, and future scalability. This guide compares the three most common form factors: SFP+, QSFP28, and QSFP-DD.
SwitchInfra publishes this guide for independent product evaluation. Brand and model names identify third-party products and do not imply manufacturer authorship or authorization.
Quick Comparison Table
| Feature | SFP+ | QSFP28 | QSFP-DD |
|---|---|---|---|
| Data Rate | 10 Gbps | 100 Gbps | 400 Gbps |
| Channels | 1 x 10G | 4 x 25G | 8 x 50G |
| Max Distance (MMF) | 400m (OM4) | 100m (OM4) | 100m (OM4) |
| Max Distance (SMF) | 40km | 40km (LR) | 2km (FR4) |
| Typical Power | 1W | 3.5W | 10-12W |
| Port Density | Standard | 2x SFP+ | 4x SFP+ |
| Cost per Port | $ | $$ | $$$ |
SFP+ (10G Transceivers)
When to Use SFP+
- Server uplinks in data center top-of-rack switches
- Enterprise aggregation layer connections
- WAN/Metro connections up to 40km
- Cost-sensitive 10GbE deployments
Common SFP+ Types
| Type | Cable | Max Distance | Typical Use |
|---|---|---|---|
| SFP-10G-SR | Multimode (OM3/OM4) | 300m / 400m | Short reach inside rack |
| SFP-10G-LR | Single-mode (OS2) | 10km | Campus/building links |
| SFP-10G-ER | Single-mode (OS2) | 40km | Long-reach WAN |
| SFP-10G-BX | Single-mode (OS2) | 10km/20km | BiDi (asymmetric) |
Compatibility Notes
- All SFP+ ports support SFP+ (10G) modules
- Most SFP+ ports are backward-compatible with SFP (1G) modules (autosensing)
- Verify switch supports DOM (Digital Optical Monitoring) if needed
QSFP28 (100G Transceivers)
When to Use QSFP28
- Data center spine-leaf uplinks
- High-performance computing (HPC) interconnects
- 100GbE switch-to-switch connections
- Short-reach to medium-reach inside data centers
Common QSFP28 Types
| Type | Cable | Max Distance | Typical Use |
|---|---|---|---|
| QSFP-100G-SR4 | MPO-12 MMF | 70m/100m | Short reach, MPO connectivity |
| QSFP-100G-LR4 | LC SMF (duplex) | 10km | Single-mode, long reach |
| QSFP-100G-PSM4 | MPO-12 SMF | 500m | Single-mode parallel fiber |
| QSFP-100G-CWDM4 | LC SMF (duplex) | 2km | CWDM, duplex LC |
| QSFP-100G-DR4 | LC SMF (duplex) | 500m | 500m data center |
QSFP28 Port Breakout
Most 100G switches support 4x25G breakout:
# Breakout one 100G port into four 25G ports
interface HundredGigE 1/1
speed forced 100Gfull
channel-group 1 mode active
QSFP-DD (400G Transceivers)
When to Use QSFP-DD
- Next-generation data center spines
- Hyperscale cloud provider networks
- AI/ML cluster interconnects (GPU-to-GPU)
- Enterprise core switches requiring 400G uplink
Common QSFP-DD Types
| Type | Cable | Max Distance | Typical Use |
|---|---|---|---|
| QSFP-DD-400G-SR8 | MPO-16 MMF | 100m | Short reach MMF |
| QSFP-DD-400G-DR4 | MPO-12 SMF | 500m | Data center 500m reach |
| QSFP-DD-400G-FR4 | LC SMF (duplex) | 2km | 2km data center interconnect |
| QSFP-DD-400G-LR4 | LC SMF (duplex) | 10km | Long-reach single-mode |
QSFP-DD Adapter Options
QSFP-DD ports can accept QSFP28 modules (backward compatible):
# Using QSFP28 in QSFP-DD port (100G mode)
interface FourHundredGigE 1/1
speed forced 100Gfull
How to Choose
Decision Flowchart
- What data rate do you need?
- 10G --> SFP+
- 100G --> QSFP28
- 400G --> QSFP-DD
- What distance?
- <100m multimode --> SR/SR4/SR8
- 500m single-mode --> DR4
- 2km --> CWDM4/FR4
- 10km+ --> LR4/LR
- What cable infrastructure exists?
- MPO/MTP (parallel MMF) --> SR4/SR8
- Duplex LC --> LR4/DR4/CWDM4
Power Consumption Impact
| Module Type | Power | Per-Switch (48 ports) |
|---|---|---|
| SFP-10G-SR | 1W | 48W |
| QSFP-100G-SR4 | 3.5W | 168W |
| QSFP-DD-400G-SR8 | 10W | 480W |
Higher power = higher cooling costs. Plan power budget accordingly.
Confirm Compatibility and Order Terms
Before ordering, confirm the exact part number, host model and firmware, port mode, cabling, and required DOM features against product-specific documentation. A matching form factor alone does not establish compatibility.
Confirm the warranty provider, coverage, duration, exclusions, and return arrangements in the written quote or order confirmation for the offered SKU. See Product and Order Policies. Existing confirmed order terms continue to apply.