All form factors
QSFP+40G·since 2010 (IEEE 802.3ba)
QSFP+, 40G aggregation, four parallel 10G lanes in one cage.
Quad SFP+, SFF-8436. Four 10.3125 Gbps electrical lanes aggregated into one module, used as native 40G (SR4/LR4/ER4) or broken out into 4× 10G SFP+ links on platforms that support it. Common in legacy data-center spines and storage networks; less common in new builds.
Specifications
MSA references
SFF-8436 (mechanical) · SFF-8636 (management)
Electrical interface
4 lanes × 10.3125 Gbps NRZ SerDes
Power consumption
1.5 W – 3.5 W per module
Signalling
Per-lane 64B/66B NRZ
FEC
None at 40G (BASE-R / FireCode FEC optional on some platforms)
Connector types
MPO-12 (SR4) · LC duplex (LR4, ER4, BiDi) · QSFP+ DAC, AOC, breakout cables
Available SKUs
| Part number | Spec | Wavelength | Fiber | Reach | Notes |
|---|---|---|---|---|---|
NAP-QSFP-SR4 | 40GBASE-SR4 | 850 nm | MM OM3/4 | 100 / 150 m | MPO-12, 4×10G VCSEL |
NAP-QSFP-LR4 | 40GBASE-LR4 | 1271/91/11/31 nm CWDM | SM | 10 km | LC duplex |
NAP-QSFP-ER4 | 40GBASE-ER4 | 1271/91/11/31 nm CWDM | SM | 40 km | Extended reach |
NAP-QSFP-PSM4 | 40G PSM4 | 1310 nm | SM parallel | 500 m – 10 km | MPO-12, 4 parallel SM |
NAP-QSFP-BIDI | 40G BiDi (Cisco-style) | 832/918 nm | MM OM3/4 | 100 / 150 m | Re-uses existing 10G MM duplex |
NAP-QSFP-DAC-1M…5M | 40G DAC | — | Twinax | 1–5 m | Passive |
NAP-QSFP-BREAKOUT-3M | 40G → 4×10G DAC | — | Twinax | 3 m | One QSFP+ to four SFP+ |
In production with
QSFP+ modules are deployed across these platforms today. Full coding details are on the compatibility matrix.
- Cisco Nexus 5K/7K/9K, Catalyst 9500/9600
- Juniper QFX5100/5110/5200, MX
- Arista 7050, 7280, 7300
- Dell S-series, Z-series (legacy)
- NVIDIA Spectrum (legacy)
Operational notes
40G is declining in new deployments, most architectures skip directly from 10G to 25G/100G. Recommended only for matching existing 40G infrastructure or specific Cisco BiDi retrofits.
40G BiDi (Cisco-style) is not an IEEE standard, wavelength pairings vary by vendor. Always pair like-with-like.
Recommended for
- Retrofit / parity with existing 40G data-center fabric
- Cisco BiDi 40G overlays on OM3/OM4 cabling plant
- 40G storage interconnect (legacy iSCSI/FCoE)
- Aggregating 4×10G access uplinks via breakout