QSFP-DD-400G-VR4: Frequently Asked Questions
Q: What is the maximum transmission distance of the QSFP-DD-400G-VR4 transceiver?
A: The QSFP-DD-400G-VR4 optical transceiver supports transmission distances of up to 50 meters over OM4 multimode fiber (MMF), subject to the module’s specifications and link configuration. Please refer to the product datasheet for the supported fiber types and maximum reach.
Q: What are the similarities and differences between the QSFP-DD-400G-VR4 and QSFP-DD-400G-VR8 transceivers?
A: Both transceivers are designed for short-reach 400G Ethernet connectivity and use eight 50G PAM4 electrical lanes. However, they differ in their optical interfaces. The 400GBASE-VR4 uses four 100G PAM4 optical lanes and typically employs an MTP/MPO-12 APC multimode fiber connector. It can connect to compatible VR4 transceivers in QSFP112 or OSFP form factors. In contrast, the 400GBASE-VR8 uses eight 50G PAM4 optical lanes and an MTP/MPO-16 APC multimode fiber connector for connections between compatible VR8 transceivers. Both solutions require matching optical specifications and compatible host interfaces.
Q: What are the main connectivity options for the QSFP-DD-400G-VR4 transceiver?
A: The QSFP-DD-400G-VR4 is designed for short-reach 400G Ethernet connections between compatible switches, network interface cards (NICs), and other networking devices. It can connect to NICs equipped with QSFP112 or OSFP ports when the corresponding VR4 optical interfaces, Ethernet protocols, and host configurations are supported. Its four 100G PAM4 optical lanes make it suitable for compatible four-lane 400G interconnect applications. Compatibility with VR8 modules should not be assumed because VR4 and VR8 use different optical lane configurations.
Q: Can a QSFP-DD-400G-VR4 transceiver be plugged directly into an OSFP port?
A: No. QSFP-DD and OSFP are physically different form factors and are not directly interchangeable. A QSFP-DD-400G-VR4 transceiver requires a compatible QSFP-DD port, while an OSFP port requires a compatible OSFP module. However, a QSFP-DD VR4 transceiver can establish an optical link with a compatible OSFP VR4 transceiver at the opposite end, provided that both modules support matching optical specifications and the host platforms are compatible.
Q: Can I connect a QSFP-DD-400G-VR4 module to a QSFP112 or OSFP 400G VR4 module?
A: Yes, cross-form-factor connectivity is possible when both modules support compatible 400G Ethernet interfaces and matching optical specifications. QSFP-DD, QSFP112, and OSFP describe the physical form factors of the modules, rather than the optical transmission protocol itself. Before deployment, verify the optical lane configuration, fiber type, connector, transmission distance, and host device compatibility.
