The QSFP+ transceiver comparison
For QSFP+ formfactor there are different variants.
I did a comparison of the optical ones - February 2014 - updated March 2018:
(without Active-Optical-Cables and Direct-Attached-Cables)
The main difference between Q.1640G.x and Q.85/1340G.x is the connector type. QSFP+ like Q.1640G.x do have an integrated CWDM Mux/Demux which multiplexes all 4 lanes to only one fiber. This gives the ability to use a LC-Duplex connector with a standard Multimode- or Singlemode-Fiber.
Some nomenclatures like LM4, LX4, IR4 are really confusing. Let me explain in short:
Note: a QSFP+ LR4 is interoperable with a QSFP+ LR4. I didn't mention this in the columen "interoperability" for a better overview. This applies to all other types as well.
* Juniper enables for their QFX-QSFP-40GE-ESR4 also 4 x 10G operations - to split up one QSFP+ port in 4 dedicated 10G ports (credits go to Tom Eichhorn for working tirelessly on the QFX tests). The same applies for Brocade. For this kind of operation they defined a special article/partnumber 40G-QSFP-SR4-INT. From a technical point of view this "split operation" is possible with all QSFP+ mentioned above. QSFP+ get always 4 x 10G from the host on the electrical side. Only the programming of the transceiver needs to be adapted for the host. On the optical path you have to check how to split up the signal in 4 dedicated 10G lines. For the ones with MTP/MPO receptacle this is not a problem with Breakout-cables.
| QSFP+ WITH LC | QSFP+ WITH MTP/MPO | |
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Some nomenclatures like LM4, LX4, IR4 are really confusing. Let me explain in short:
- LM4: Is long-range Multimode (100-140m OM3 / up to 160m on OM4)
- IR4: Is 2km on Singlemode
- LX4: Combines both - 2km Singlemode and 100-160m Multimode
| Description/ Connector | Distance | Wavelength | Connector | Details | Interoperability | Provider |
| QSFP+ SR4 | 100m (OM3) 150m (OM4) | 4 x 850nm | MTP/MPO | IEEE 802.3ba (40GBASE-SR4) | QSFP+ extended SR4 SFP+ SR |
Flexoptix
Q.8540G.02 Cisco QSFP-40G-SR4 Juniper QFX-QSFP-40GE-SR4 Arista 40GBASE-SR4 Brocade 40G-QSFP-SR4* |
| QSFP+ eSR4 | 300m (OM3) 400m (OM4) |
4 x 850nm | MTP/MPO | optimized VCSEL with better performance of RMS spectral width compared with QSFP+ SR4 | QSFP+ SR4 SFP+ SR |
Flexoptix
Q.8540G.03 Juniper QFX-QSFP-40GE-ESR4* Arista 40GBASE-XSR4 |
| QSFP+ LX4 | 150m (OM3) 160m (OM4) |
1270nm, 1290nm, 1310nm, 1330nm | LC | Multimode optimized 4-Kanal CWDM Mux/Demux inside |
Flexoptix
Q.1640G.03 Juniper JNP-QSFP-40G-LX4 |
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| QSFP+ BIDI SR | 100m (OM3) 120m (OM4) |
1 x 850nm 1 x 900nm |
LC | BIDI for Multimode is hot! 20G per lambda! |
only available from Cisco at the moment | Cisco QSFP-40G-SR-BD |
| QSFP+ IR4 | 1km (G.652) | 1270nm, 1290nm, 1310nm, 1330nm | LC | 4-Channel CWDM Mux/Demux inside | SFP+ CWDM | Flexoptix
Q.1640G.2 Arista 40GBASE-LRL4 Juniper JNP-QSFP-40GE-IR4 |
| QSFP+ LR4 | 10km (G.652) | 1270nm, 1290nm, 1310nm, 1330nm | LC | IEEE 802.3ba (40GBASE-LR4) 4-Channel CWDM Mux/Demux inside |
SFP+ CWDM | Flexoptix
Q.1640G.10 Juniper JNP-QSFP-40G-LR4 Cisco QSFP-40G-LR Arista 40GBASE-LR4 Brocade 40G-QSFP-LR4 |
| QSFP+ LR4 | 10km (G.652) | 1270nm, 1290nm, 1310nm, 1330nm | LC | IEEE 802.3ba (40GBASE-LR4) 4-Channel CWDM Mux/Demux inside |
SFP+ CWDM | Flexoptix Q.1640G.20 |
| QSFP+ ER4 | 30km (G.652) | 1270nm, 1290nm, 1310nm, 1330nm | LC | IEEE 802.3ba (40GBASE-ER4) | SFP+ CWDM | Flexoptix Q.1640G.40 |
| QSFP+ PIR4 | 1km (G.652) | 4 x 1310nm | MTP/MPO APC | 4 x 10G operations on SMF | QSFP+ parallel LR4 SFP+ LR | Flexoptix
Q.1340G.2 Arista 40GBASE-PLRL4 Juniper JNP-QSFP-4x10GE-IR |
| QSFP+ PLR4 | 10km (G.652) | 4 x 1310nm | MTP/MPO APC | 4 x 10G operations on SMF | QSFP+ short parallel LR4 SFP+ LR |
Flexoptix
Q.1340G.10 Arista 40G-PLR4 |
* Juniper enables for their QFX-QSFP-40GE-ESR4 also 4 x 10G operations - to split up one QSFP+ port in 4 dedicated 10G ports (credits go to Tom Eichhorn for working tirelessly on the QFX tests). The same applies for Brocade. For this kind of operation they defined a special article/partnumber 40G-QSFP-SR4-INT. From a technical point of view this "split operation" is possible with all QSFP+ mentioned above. QSFP+ get always 4 x 10G from the host on the electrical side. Only the programming of the transceiver needs to be adapted for the host. On the optical path you have to check how to split up the signal in 4 dedicated 10G lines. For the ones with MTP/MPO receptacle this is not a problem with Breakout-cables.