Sfp+ cable connection to jetson thor

Robotics & Edge Computing Jetson Systems Jetson Thor
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1

Hi all,

I’m trying to connect a USRP X310 SDR (which has a 10GbE SFP+ interface) to a Jetson Thor AGX module for high-throughput RF data streaming. I have a few related questions and am running into issues - would appreciate any guidance.

My setup

  • USRP X310 with 10GbE SFP+ port

  • Jetson Thor (QSFP28 port - mgbe0_0 through mgbe3_0)

  • Cisco CVR-QSFP-SFP10G QSA adapter (QSFP to SFP+)

  • UHD driver, tested with uhd_usrp_probe and a streaming application

Questions

1. Will the CVR-QSFP-SFP10G adapter work with the Jetson Thor QSFP28 port?
The Thor’s QSFP28 port is spec’d for 100G, but I need it to fall back to 10G SFP+ mode via the QSA adapter. Does the Mellanox ConnectX NIC on Thor (mlx5_core) support this adapter and auto-negotiate to 10G correctly? Is there anything special needed to force 10G link speed?

2. Do I need a dedicated breakout cable instead?
I’ve seen QSFP28-to-SFP28 active optical or DAC breakout cables mentioned as an alternative. Is a QSA adapter (like the Cisco CVR) sufficient, or is a proper breakout cable required to avoid issues with the MGBE lane configuration?

3. Recommended system tuning for UHD streaming
Once the link is up, what are the recommended network settings for stable UHD streaming? I’m thinking jumbo frames (MTU=9000), socket buffer tuning (net.core.rmem_max, net.core.wmem_max) - any Thor-specific guidance here?

Issue: sync errors on streaming

When I ran a basic streaming session, I got repeated S (sequence/sync) errors in the UHD output. This suggests sample drops or timestamp mismatches. The link appeared to come up, but I’m not sure if it’s negotiating at the correct speed or if the MGBE driver needs additional configuration.

Specifically, are there known issues with the mlx5_core driver on Jetson Thor with QSA adapters at 10G speeds? Is there a way to verify the negotiated link speed and check for packet drops at the driver level?

Environment

  • JetPack version: 7.1

  • UHD version: 4.5.0.00

Thanks in advance - any guidance on adapter compatibility, driver config, and UHD tuning for this setup would be really helpful.

4

We have some tricks here to enhance the perf. Maybe that would also help your streaming case.

echo 1 > /sys/devices/platform/bus@0/a808a10000.ethernet/net/mgbe0_0/threaded
echo 1 > /sys/devices/platform/bus@0/a808e10000.ethernet/net/mgbe3_0/threaded
echo 1 > /sys/devices/platform/bus@0/a808b10000.ethernet/net/mgbe1_0/threaded
echo 1 > /sys/devices/platform/bus@0/a808d10000.ethernet/net/mgbe2_0/threaded
5

Unfortunately, it didn’t help.

6

Do you have any method to reproduce the issue you hit on NV devkit?

Just want to clarify. The thing you are asking here is not any kind of known issue.

UHD test with USRP was not conducted on our side.

7

In theory this should work if MGBE is configured for 10G but this specific adapter has not been validated by NVIDIA.

8

Is there any adapter or cable that was validated with the jetson Thor?

9

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.