40GBASESR4

40GBASE-SR4 is an Ethernet standard defined by the IEEE 802.3ba specification, designed for high-speed data transmission over multimode fiber optic cables. It supports a data rate of 40 gigabits per second, making it suitable for demanding network applications such as data centers, high-performance computing, and storage area networks. The "SR4" designation indicates it uses Short Reach (SR) transmission and is based on four parallel fibers, with each fiber carrying one lane of data.

The standard utilizes a QSFP+ (Quad Small Form-factor Pluggable Plus) transceiver form factor. Each QSFP+ module for 40GBASE-SR4 contains 12 fibers: four transmit fibers and eight receive fibers. Four of the receive fibers are used for the 40Gbps transmission, and the remaining four are for a separate 10Gbps channel for backward compatibility or other functions. It operates over standard multimode fiber, typically OM3 or OM4, and supports link lengths up to 100 meters for OM3 and 150 meters for OM4. This makes it a cost-effective solution for short-distance, high-bandwidth connections within racks or across a data center floor.