Strange Problem with Ethernet Connectivity on DGS-108/GS108 Switches

Hi,

I have a very strange problem with respect to connectivity on DGS-108/GS108 switches.

Background: I am working on developing a embedded hardware which uses i.MX8M Mini System on Chip. Atheros AR8031 Ethernet Trans-receiver is installed on this board. This embedded hardware runs a minimal variant of Linux OS which supports the Ethernet software stack which supports the installed trans-receiver. The embedded hardware supports speeds upto 1Gigabit/s

On the Linux OS running on the embedded hardware, we have configured a Static IP of 192.168.13.200, Netmask 255.255.252.0 and Gateway of 192.168.12.240 by default on boot. (DHCP can also be enabled, but for testing we have kept it as static)

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I am facing the following issues/observations. In all of the cases mentioned where I have used a switch, there is no other device connected to the switch other than the embedded board.

Observation #1: When I connect the Ethernet cable (Cat-6 RJ45) from embedded board to a Host PC (Windows 10 PC) directly, ie one-to-one connection, the Ethernet link is up within 2 seconds and the speeds are set at 1Gbps after auto negotiation (Confirmed from Windows and also the lights on the embedded board, LINK LED is GREEN, SPEED LED is GREEN).

Observation #2: When I connect the Ethernet cable from embedded board to a managed switch (DLink DGS-1100-5), the Ethernet link is up withing 2 seconds and the speeds are also set at 1Gbps after auto-negotiation. (Confirmed from Windows and also the lights on the embedded board, LINK LED is GREEN, SPEED LED is GREEN).

Observation #3: When I connect the Ethernet cable from embedded board to a unmanaged switch (DLink DGS-108), the board is stuck at auto-negotiation. The Ethernet link gets up momentarily(~500ms) before going down again. The Ethernet LEDS are always blinking, i.e in the same pattern as when they are trying auto-negotiation.

Observation #4: When I connect the Ethernet cable from embedded board to a unmanaged switch (Netgear GS108), the Ethernet link is up, but the speed is set to 100Mbps. The Ethernet LEDS on the embdded board are set to, LINK LED is GREEN and SPEED LED is AMBER.

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TLDR:

My custom embedded device supports 1Gbps Ethernet(Atheros AR8031) and it runs a minimal Linux OS which supports the Ethernet Stack

1) When I connect my custom embedded device to DLINK DGS-108 switch the Ethernet link is not stable, it is always stuck in Auto negotiation

2) When I connect my custom embedded device to NETGEAR GS108 switch the Ethernet link stable, but stuck at 100Mbps

3) When I connect my custom embedded device to DLINK DGS-1100-5 switch the Ethernet link stable, and I get 1Gbps

4) When I connect my custom embedded device to Windows PC directly the Ethernet link stable, and I get 1Gbps