Standardized by the IEEE P802.3cm Task Force, 400G-SR8 QSFP-DD/OSFP transceivers are designed to provide cost-effective short-range transmission by adopting 16-fiber parallel multimode MTP cables.
In accordance with the protocol IEEE 802.3bs Task Force, 400G-DR4 QSFP-DD/OSFP transceivers adopt 8-fiber or 12-fiber parallel single mode MTP cables, which can achieve 500m reach.
Unlike the previous two, the 400G-FR4 interface only utilizes 4 lasers instead of 8 lasers to multiplex them into one fiber in each direction. 400G-FR4 QSFP-DD/OSFP modules are normalized by the 100GLambda MSA to provide long-range transmission with 2-fiber single mode LC cables.
Consequently, MTP cabling is mainly used together with 400G-DR4 and 400G-SR8 optical transceivers in 400G networks, which can be further divided into 8-fiber, 12-fiber, 16-fiber SMF and MMF MTP cables types.
