Intel® Ethernet 800 Series Linux Flow Control
Configuration Guide for RDMA Use Cases
QoS/Flow Control Limitations on the 800 Series
- Although the
800 Series hardware supports eight Traffic Classes (TCs), the maximum supported configuration is four TCs per port. Only one TC can have Priority Flow Control enabled per port.
Number of Adapter Ports | Traffic Class Recommendation | RDMA |
---|---|---|
1, 2, or 4 | Up to four TCs, with one of them enabled with PFC. | Supported |
More than 4 | No DCB Support | Not Supported |
- In RoCEv2 mode, if no flow control is detected (either LFC or PFC), the driver automatically de-tunes. This is an intentional design to allow RoCEv2 to operate without flow control, but with lower performance.
- When the 800 Series is in firmware Link Layer Discovery Protocol (LLDP) mode, only three application priorities are supported. Software LLDP supports 32. This refers to the LLDP APP TLV - see
man lldptool-app for more info.