Should an AI cluster use 400G or 800G?
Choose by topology, host generation and bandwidth target. Both rates may coexist across node, Leaf and Spine layers.
AI Compute and GPU Clusters
AI Cluster Optical Interconnect: 400G and 800G Selection
Plan AI cluster optics by GPU, Leaf and Spine position, then match form factor, reach, fiber, thermal limits, FEC and breakout mode.
Selection FAQ
Scenario selection questions
How should 800G reach be selected?
Evaluate VR8/SR8 for MMF, DR8 for 500m-class parallel SMF and 2xFR4 for 2km-class SMF, subject to the exact host and PMD.
What must be validated?
Validate host coding, FEC, errors, optical power, power draw, temperature, link flap, fiber mapping and long-duration stability.
Typical Scenarios
Typical deployment positions
01
GPU node uplinks
Match the NIC, switch port, rack distance and cable path.
02
Leaf-Spine fabric
Plan 400G and 800G links by reach, fiber and port density.
03
High-density breakout
Validate host breakout, lane mapping, cabling, FEC and every remote endpoint.
Selection Guide
Scenario selection priorities
Host form factor and lane mode
Power and thermal design
MPO, LC or CS cabling
FEC, errors and long-duration stability
Recommended Products
Recommended product directions
800G Optical Transceivers: OSFP and QSFP-DD → 800G Optical Transceivers: OSFP and QSFP-DD covering 800G OSFP SR8, 800G OSFP VR8, 800G OSFP DR8, 800G QSFP-DD DR8, 800G OSFP 2xFR4, 800G QSFP-DD 2xFR4 and related cable directions. Compare OSFP and QSFP-DD form factors, 800G optical modules, reach and breakout directions. 400G Optical Transceivers → 400G Optical Transceivers covering 400G QSFP-DD SR8, 400G OSFP SR4, 400G QSFP112 SR4, 400G QSFP-DD DR4, 400G QSFP-DD FR4, 400G QSFP-DD LR4 and related cable directions. Includes 400G QSFP-DD, OSFP and QSFP112 transceivers for data-center and high-speed interconnect planning.
400G Optical Transceivers
400G QSFP-DD AOC
QSFP-DD to QSFP-DD Custom length
800G Optical Transceivers: OSFP and QSFP-DD
800G OSFP SR8
MPO-16 100m OM4
800G Optical Transceivers: OSFP and QSFP-DD
800G OSFP DR8
MPO-16 500m
800G Optical Transceivers: OSFP and QSFP-DD
800G QSFP-DD DR8
MPO-16 500m
800G Optical Transceivers: OSFP and QSFP-DD
800G OSFP 2xFR4
Dual Duplex LC 2km
800G Optical Transceivers: OSFP and QSFP-DD
800G QSFP-DD 2xFR4
Dual CS 2km
Related Solutions
Technical solutions for this application
High-Speed Optical Interconnect Solutions
High-Speed Optical Interconnect Solutions
100G–800G modules and links
View solution →AOC / DAC Short-Reach Links
AOC / DAC Short-Reach Links
Servers, racks and breakout
View solution →Compatibility Validation
Compatibility Validation
Multi-vendor samples and rollout
View solution →Selection Guides
Technical guides for this application
800G SR8 vs VR8 vs DR8 vs 2xFR4
Compare 50m, 100m, 500m and 2km PMD directions for AI fabrics.
Read guide →Optical link budget calculation
Record loss, margin, receiver sensitivity and overload on the final path.
Read guide →Optical transceiver procurement checklist
Prepare host, FEC, sample and batch-acceptance fields before RFQ.
Read guide →