Appendix A: Additional Guidelines and Equipment Details
64
Dell EMC PowerEdge MX
Networking Architecture Guide
Figure 55. QSFP28 cables: Multi-fiber Push On (MPO) Cable
Figure 56. QSFP28 cables: Active Optical Cable (AOC)
Note:
The QSFP28 form factor can use the same MPO cable as QSFP+. The DAC and AOC
cables are different in that the attached transceiver is a QSFP28 transceiver rather than QSFP+.
QSFP28 supports the following breakout configurations:
•
1x40Gb
with QSFP+ connections, using either a DAC, AOC, or MPO cable and
transceiver.
•
2x50Gb
with a fully populated QSFP28 end and two de-populated QSFP28 ends,
each with 2x25GbE lanes. This product is only available as DAC cables.
•
4x25Gb
with a QSFP28 connection and using 4 SFP28 connections, using either a
DAC, AOC, or MPO breakout cable with associated transceivers.
•
4x10Gb
with a QSFP28 connection and using 4 SFP+ connections, using either a
DAC, AOC, or MPO breakout cable with associated transceivers.
Rate limited 32 Gb Fibre Channel
When using 32 Gb FC, the actual data rate is 28 Gbps due to 64b/66b encoding. Figure
50 shows one of the unified interfaces, port groups 15 and 16. The port group is set to 4x
32 Gb FC mode. However, each of the four lanes is 25 Gbps, not 28 Gbps. When these
lanes are mapped from the Network Processing Unit (NPU) to the FC ASIC, for
