Hi,
We are evaluating the feasible port splitting option for the 2x QSFP112 ports. Our understanding is ConnectX-7 provides up to 4 physical SerDes channels at 112Gb/s PAM4 per adapter. In dual-port adapter configurations, the 4-lane SerDes macro is partitioned equally: Port 1 is assigned Physical Lanes 0–1, and Port 2 is assigned Physical Lanes 2–3, providing NDR200 (2x 100G PAM4) capability per port. Based on the above, each port can breakout up to 2x links totaling 4x links. Please help to confirm if our understanding is correct or otherwise.
Regards,
Sean
The QSFP112 port breakout (2×100G per port, 4 links total) looks feasible from a ConnectX-7 capability standpoint, but we have not verified this configuration on IGX T7000. Also please note that the Thor SoC connects to CX-7 via PCIe Gen5 x8, which provides a theoretical maximum bandwidth of ~252 Gbps — so the aggregate throughput across all links would be limited accordingly.
Hi Eric,
Thanks for your reply.
After further research (see below 2 sources), it appears that port splitting was not supported for ConnectX-7 with dual-port QSFP112 200Gb/s setup. As you mentioned, Thor SoC connects to CX-7 differently, which also involving CX-7 acting as a PCIe switch to offer additional 1x X16 and 1x X8 slots. Can you please help check again if QSFP112 on IGX T7000 has the same limitation as MCX755106AS-HEAT (or other equivalent) or otherwise?
The IGX T7000 officially supports the QSFP112 configuration as documented. Any port splitting or breakout beyond the documented specification is not supported.