MGBE SGMII 2.5G Link

Hi,

We are currently deploying an NVIDIA Jetson Orin module on a custom carrier board and are facing some issues when bringing up the network interfaces.

We have connected the Jetson Orin’s MGBE interface to an SGMII interface on a network switch (a direct MAC-to-MAC connection). The issue is that the maximum speed supported by this switch port is 2.5 Gbit/s, whereas on the NVIDIA side, the MGBE interface’s minimum configurable speed—both in the drivers and in the bootloader SERDES configuration—is 5 Gbit/s.

Is it possible to configure the MGBE interface to operate at 2.5 Gbit/s?

Thanks!

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The question is about configuring the MGBE interface on the NVIDIA Jetson Orin module to operate at 25 Gbits, as the minimum configurable speed on the NVIDIA side is 5 Gbits, but the network switch port only supports up to 25 Gbits.

Unfortunately, the provided context does not explicitly mention the maximum configurable speed of the MGBE interface on the Jetson Orin module. However, it does mention that the PCIe x4 interface (PCIE0) operates up to Gen4 speed, which is 16 GT/s per lane, resulting in a total bandwidth of 64 GT/s or 64 Gbps. However, this is not directly related to the MGBE interface.

In general, the MGBE (Multi-Gigabit Ethernet) interface is a high-speed Ethernet interface that can operate at various speeds, including 1 Gbps, 2.5 Gbps, 5 Gbps, and 10 Gbps. However, the context does not provide information on whether the Jetson Orin module’s MGBE interface can be configured to operate at 25 Gbps.

It is possible that the Jetson Orin module’s MGBE interface may not support 25 Gbps, as this speed is not commonly used in Ethernet interfaces. However, without further information or clarification from NVIDIA, it is difficult to provide a definitive answer.

In comparison, the Jetson AGX Orin series and Jetson Orin NX series have similar power management features, but the context does not provide information on the MGBE interface’s configurable speeds for these modules.

To resolve the issue, it is recommended to consult the NVIDIA Jetson Orin module’s documentation, specifically the section on MGBE interface configuration, or contact NVIDIA support for further clarification. Additionally, it may be necessary to consider using a different network switch or interface that supports the minimum configurable speed of the MGBE interface on the Jetson Orin module.

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The context is allways Multi Gigabit Ethernet, not PCIe. Maximum speed of switch is 2.5G not 25G. You claim that MGBE supports 1, 2.5, 4 and 10… but in think that this is with the presence of a PHY, the USXGMII interface is always 5G or 10G, right?

Hi,

I am not sure but auto-neg shall be able to adjust to 2.5Gbits/s when your switch only supports up to 2.5.

Hi @WayneWWW

Autoneg it is not working, and 2.5G, on the lower layer, is quite different from 5g (Codification, speed…)

The thing is that the Nvidia MGBE manual claims that the Serdes can reach 2.5 but it was impossible for me to make this work.

I’ve tried several configs with autoneg enabled and disabled 10G and 5G, XFI or USXGMII on the Nvidia side… and different configs on the phy side.