Channel Insertion Loss
Channel insertion loss is the loss of signal power resulting from the insertion of a device in a transmission line or optical fiber and is usually expressed in decibels (dB).
The following table describes the BlueField-3 DPU channel insertion loss budget for PCIe Gen 5.0 architecture (32 GT/s).
The total PCIe channel insertion loss approved by PCI-SIG Gen5.0 spec is 36dB @16GHz.
The total BlueField-3 DPU board insertion loss of the PCIe lanes (PCORE1) routed to the Cabline CA-II Plus is 6dB (@16GHz).
The Passive PCIe Auxiliary Card Loss is 1.5dB (@16Ghz).
The Cabline CA-II Plus harness loss at 16GHz:
|
Harness Length |
Channel Loss at Gen 5.0 |
|
15cm |
3.8dB |
|
35cm |
7.6dB |
|
55cm |
11.4dB |
The above is measured data; it is recommended to add 0.5dB margins for your system (some loss variations are possible).
The Cabline CA-II Plus harnesses loss = 0.24dB/cm for Gen 5.0.
The above loss includes the Cabline CA-II Plus harnesses and connectors on both sides.
The PCI-SIG Gen5 SPEC also defines the total loss for AIC (bump to Golden-Fingers) to be 9.5dB @16Ghz.
The BlueField-3 AIC, together with a 15cm Cabline CA-II Plus harnesses and the Passive PCIe Auxiliary Card loss is: 3dB+2dB+3.8dB+1.5dB=10.3dB > 9.5dB