Intel 82599ES with 10Gtek DACs and transceivers: link flaps up and down on Linux and FreeBSD
Used Intel 82599ES 10-Gigabit SFI/SFP+ NICs from eBay were connected with 10Gtek SFP+ DACs and, via QNAP switches, with 10Gtek SR transceivers over OM3. On Linux dmesg looped NIC Link is Up 10 Gbps / NIC Link is Down; on FreeBSD the interface showed no carrier and DHCP failed. allow_unsupported_sfp=1 was already set on Linux, and Intel-coded FTLX8571D3BCV-IT optics still flapped on FreeBSD.
- Hardware: Intel 82599ES, QNAP 10G switch, Chelsio S310, Myricom Myri-10G
- Transceivers: 10Gtek SFP+ DAC, 10Gtek XDACBL2M, 10Gtek 10G SR SFP+, Intel FTLX8571D3BCV-IT
- Form factor: SFP+, DAC
Symptoms / messages:
NIC Link is Up 10 Gbps ... NIC Link is Down (repeating)
no carrier
DHCP failure
Comments 2
Use 10Gtek's Intel-specific DAC (XDACBL2M), disable FEC/auto-negotiation with ethtool, and test switch-to-server cabling in isolation.
The poster gave up on the Intel cards: a Chelsio S310 (under 20 USD used) and a Myricom Myri-10G with matching transceivers linked at full 10G immediately.