Can QSFP28 and SFP+ be directly connected over optical fiber? if not, what connection structure is required between Thor EVM and Lattice HSB?

Robotics & Edge Computing Jetson Systems Jetson Thor
1

Hello,
I am trying to connect an NVIDIA Thor EVM to a Lattice HSB.
What i want to confirm is whether a QSFP28 port and an SFP+ port can be connected directly over optical fiber.

My main questions are:

  1. Is direct connection possibel between QSFP28(Thor) and SFP+(HSB)?

    • Thor EVM QSFP28
    • Lattice HSB SFP+
    • Using optical transceivers and fiber only

  2. If direct connection is not possible, what is the correct or recommended structure?

If anyone has connected Thor EVM and Lattice HSB successfully, i would appreciate an example connection diagram or module P/N

Thank you

4

Theoretically, your proposed connection should be possible since:

  1. Thor has 4x independent MGBE controllers, where each of these controllers can be configured as either 25G or 10G.
  2. The QSFP28 connector on Thor Dev Kit will be working either as 4x25G or 4x10G.

Based on this, you could consider:

  1. Configure MGBE controllers to run at 10G, such that all 4x MGBE lanes connected to QSFP28 result in 4x10G.
  2. Connect a QSFP+ active optical breakout cable to Thor EVM, to split the single QSFP+ (4x10G) into 4xSFP+ connectors. An example of such breakout cable: Cisco QSFP-4X10G-AOC1M Active Optical Cable.
  3. Connect one of the SFP+ connectors of the breakout cable to the Lattice HSB SFP+.

Note that these are only assumptions and have NOT been tested by NVIDIA. This only serves as general guidance and is not guaranteed, for you to try at your own discretion.

5

This works for me on Thor with Jetpack 7.1 r38.4.

NVIDIA/Mellanox MC2609130-050 Compatible QSFP+ to 4SFP+ Ethernet Passive Breakout Copper Cable

qsfp+ end of cable into Thor.

Two sfp+ into Lattice LF-SNSR-ETH-EVN holoscan-sensor-bridge
One sfp+ into QNAP QSW-2104-2S-A 10GB switch, to LAN, WAN.
One sfp+ into x86_64 workstation.