10G networking woes - Sodola 8port SFP+ switch with Unifi UDM-SE

Very strange networking throughput woes here … These are the items in play

  • Comcast XFinity modem
  • Unifi UDM-SE gateway
  • Sodola 8-port SFP+ switch SL-SWTGW2C8F (Amazon part B0CQJCQ17Q)
  • 10Gtek dual SFP+ 10Gb PCI-E NIC with Broadcom BCM57810S Chipset in server (Amazon part B06XHGFD69)
  • Various 10G/5G/2.5G/1G copper transceivers, 10G fiber tranceivers

When server is connected directly to UDM SFP+ port via 10G copper, can download at full speed (40-80MB/s). When server is connected to the Sodola 8-port SFP+ switch (copper or fiber) which then connects to UDM-SE SFP+ port (fiber), download is barely 1MB/s.

Enabling or disabling flow control on the two ports in use in the Sodola switch has no effect on throughput. Switch shows 10G speed and full duplex negotiated.

So, this gives expected throughput

            copper                   copper
server(10G) ====== (10G)UDM-SE(2.5G) ===== Modem

While this totally sucks

            fiber                  fiber                   copper
server(10G) ----- (10G)Sodola(10G) ----- (10G)UDM-SE(2.5G) ===== Modem

iperf3 tests TO the server have tons of retries, though throughput is more or less what’s expected
iperf3 tests FROM the server are much better, only a few retries

Any ideas ? Nice as it would be to go all Unifi, the switch options just aren’t there for what I want. Not to mention the Unifi-tax …

Looks like it was the Sodola switch (actually tried two different ones). Got a Mikrotik CSR-1G-10S-IN over the weekend (amazon next-day rocks) and it all works fine now. Literally just moved the optics and cables from Sodola to Mikrotik, powered it on and poof, full speed.