Intel X550-T2 problem with 2.5 Gbps link speed

[madbrain]

I tried Opensense 23.1 with the above NIC. When connected to the Comcast XB7 2.5 Gbps port, the NIC only negotiates 1 Gbps. The XB7's Ethernet port LED is orange, indicating 1 Gbps. Internet throughput through Opensense also tops at 1 Gbps.

When I use the closed-source pfSense 2.6 with the same box/NIC, the XB7 Ethernet lights turns green, indicating a 2.5 Gbps link. I'm able to achieve Internet throughput >1 Gbps in this case (1.4). pfSense reports the WAN link speed as "unknown" in this case, but it does work and is really 2.5 Gbps.

Somehow, the X550-T2 driver in Opensense has a problem with 2.5 Gbps speed. It works fine at 1 Gbps and 10 Gbps, but not 2.5 Gbps (I didn't try 5 Gbps speed as I don't have any 5 Gbps devices).

I'd love to move to the open-source version, but this is issue is currently holding me on pfSense 2.6 .

[meyergru]

I found this to happen under Linux and Windows, too. For some reason, the advertised speeds are 100, 1000 and 10000 for those Intel adapters, whereas the supported speeds are 2500 and 5000 as well. The Intel reference documentation even states that autonegotiation is not supported for 2500 Gbps.

Under Linux, this looks like so if the other side can only do 100,1000 and 2500:

Code: [Select]

# ethtool eth4
Settings for eth4:
        Supported ports: [ TP ]
        Supported link modes:   100baseT/Full
                                1000baseT/Full
                                10000baseT/Full
                                2500baseT/Full
                                5000baseT/Full
        Supported pause frame use: Symmetric
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  100baseT/Full
                                1000baseT/Full
                                10000baseT/Full
        Advertised pause frame use: Symmetric
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Speed: 1000Mb/s
        Duplex: Full
        Auto-negotiation: on
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        MDI-X: Unknown
        Supports Wake-on: d
        Wake-on: d
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes

Since the latter two modes are not advertised, they will not get negotiated, but must be set explicitely. After setting 2500, ethtool says:

Code: [Select]

# ethtool eth4
Settings for eth4:
        Supported ports: [ TP ]
        Supported link modes:   100baseT/Full
                                1000baseT/Full
                                10000baseT/Full
                                2500baseT/Full
                                5000baseT/Full
        Supported pause frame use: Symmetric
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  2500baseT/Full
        Advertised pause frame use: Symmetric
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Speed: 2500Mb/s
        Duplex: Full
        Auto-negotiation: on
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        MDI-X: Unknown
        Supports Wake-on: d
        Wake-on: d
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes

I do not know if pfSense does something special in their driver to advertise more modes or if they just try different modes from highest to lowest until they succeed, however, that is not standard behaviour for this hardware. I have read something to the extent that 2500 Gbps is not stable depending on the link partner.

I do not have this NIC under OpnSense, but you can probably manually set 2500 Gbps as well.

[madbrain]

Thanks. How would I go about forcing that speed manually ? Sorry, pfSense/Opensense newbie here.

[meyergru]

In an ideal world, it should be selectable in the interface section, but I do not know for sure, since I do not have that type of adapter running in OpnSense.

[madbrain]

In an ideal world, it should be selectable in the interface section, but I do not know for sure, since I do not have that type of adapter running in OpnSense.

Thanks. I was able to force the NIC manually to 2500Base-T on the WAN side. The LED is green indicating full 2.5Gbps speed. However, I'm only getting 300 Mbps in Ookla speedtest. Same if the NIC is at 1 Gbps. I rebooted both Opensense and the Comcast XB7 modem (gateway, in bridge mode) but I'm getting 300 Mbps max download speed regardless.

This is with a fresh install of Opensense, except for having migrated the DHCP server settings (static DHCP reservations) from the pfSense config.


If I reboot to pfSense (I have a SATA hotswap bay) I get the full 1.4 Gbps download speed, so I know it's something to do with the Opensense configuration that's messing with the performance.


False alarm. It's something with the Comcast modem, not Opensense. Rebooting to pfSense still showed 300 Mbps. I then switched the Comcast XB7 to router mode, and got the full 1.4 Gbps. Back to bridge mode and pfSense, still 1.4 Gbps. Rebooted to Opensense after this, and got 1.4 Gbps too. So weird.

Hardware is
Asus Prime X470 Pro motherboard
AMD 5700g CPU
2x8GB DDR4 2666
Intel X550-T2 NIC
64GB SATA SSD