400G OSFP Transceiver Types Overview

Posted on December 23, 2019
July 10, 2020
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OSFP stands for Octal Small Form-factor Pluggable, which consists of 8 electrical lanes, running at 50Gb/s each, for a total of the bandwidth of 400Gb/s. This post will give an introduction of 400G OSFP transceiver types, the fiber connections, and some QAs about OSFP.

400G OSFP Transceiver Types

Below lists some current main 400G OSFP transceiver types: OSFP SR8, OSFP DR4, OSFP DR4+, OSFP FR4, OSFP 2*FR4, and OSFP LR4, which summarize OSFP transceiver according to the two transmission types (over multimode fiber and single-mode fiber) they support.

Transmission Type OSFP Product Description Reach Optical Connector Wavelength Optical Modulation Protocol
Multimode fiber 400G OSFP SR8 up to 100m over parallel MMF MTP/MPO-16 850nm 50G PAM4 IEEE P802.3cm;IEEE 802.3cd
Single-mode fiber 400G OSFP DR4 up to 500m over parallel SMF MTP/MPO-12 1310nm 100G PAM4 IEEE 802.3bs
4000G OSFP XDR4/DR4+ up to 2km over parallel SMF MTP/MPO-12 1310nm 100G PAM4 /
400G OSFP FR4 up to 2km over duplex SMF LC CWDM4 wavelength 100G PAM4 100Glambda MSA
400G OSFP 2FR4 up to 2km over duplex SMF CS CWDM4 wavelength 50G PAM4 IEEE 802.3bs
400G OSFP LR4 up to 10km over duplex SMF LC CWDM4 wavelength 100G PAM4 100Glambda MSA

Fibers Connections for 400G OSFP Transceivers

400G OSFP SR8

  • Connect a 400G OSFP SR8 transceiver with another 400G OSFP SR8 transceiver over an MPO-16 cable.

  • Figure 1 OSFP SR8 to OSFP SR8.jpg
  • 400G OSFP SR8 to 2*200G SR4 over MTP-16 to 2*MPO-8 breakout cable.

  • Figure 2 OSFP SR8 to 2 200G SR4.jpg
  • 400G OSFP SR8 to 8*50G SFP via MTP-16 to 8*LC duplex breakout cable with up to 100m.

  • Figure 3 OSFP SR8 to 8 50G SFP.jpg

400G OSFP DR4

400G OSFP DR4 to 4*100G DR4 over MPO-12 to 4*LC duplex breakout cable.

Figure 4 OSFP DR4 to 4 100G DR.jpg

400G OSFP XDR4/DR4+

400G OSFP DR4+ to 4*100G DR over MPO-12 to 4*LC duplex breakout cable.

Figure 5 OSFP DR4+ to 4 100G DR.jpg

400G OSFP FR4

400G OSFP FR4 to 400G OSFP FR4 over duplex LC cable.

Figure 6 OSFP FR4 to OSFP FR4.jpg

400G OSFP 2FR4

OSFP 2FR4 can break out to 2*200G and interop with 2*200G-FR4 QSFP transceivers via 2*CS to 2*LC duplex cable.

Figure 7 OSFP DR4+ to 2 200G FR.jpg

400G OSFP Transceivers: Q&A

Q: What does "SR8", "DR4", "XDR4", "FR4", and "LR4" mean?

A: "SR" refers to short range, and "8" implies there are 8 optical channels. "DR" refers to 500m reach using single-mode fiber, and "4" implies there are 4 optical channels. "XDR4" is short for "eXtended reach DR4". And "LR" refers to 10km reach using single-mode fiber.

Q: Can I plug an OSFP transceiver module into a QSFP-DD port?

A: No. QSFP-DD and OSFP are totally different form factors. For more information about QSFP-DD transceivers, you can refer to 400G QSFP-DD Transceiver Types Overview. You can use only one kind of form factor in the corresponding system. Eg, if you have an OSFP system, OSFP transceivers and cables must be used.

Q: Can I plug a 100G QSFP28 module into an OSFP port?

A: Yes. A QSFP28 module can be inserted into an OSFP port but with an adapter. When using a QSFP28 module in an OSFP port, the OSFP port must be configured for a data rate of 100G instead of 400G.

Q: What other breakout options are possible apart from using OSFP modules mentioned above?

A: OSFP 400G DACs & AOCs are possible for breakout 400G connections. See 400G Direct Attach Cables (DAC & AOC) Overview for more information about 400G DACs & AOCs.