Intel® Ethernet 800 Series Linux Flow Control
Configuration Guide for RDMA Use Cases
Assigning an Application to a Traffic Class
In Linux, there is a chain of mappings for VLAN PFC that starts with setting the ToS field in the IPv4/6 header that ultimately determines traffic class:
Type of Service (ToS) → Kernel Priority (sk_prio) → User Priority (UP) → Traffic Class (TC)
If using DSCP, the chain of mapping is:
Type of Service (ToS) → DSCP → User Priority (UP) → Traffic Class (TC)
QoS values, like bandwidth allocations or drop/no-drop characteristics, can then be applied to each TC. This applies whether you're using explicit VLANs or VLAN 0.
The rest of this section outlines the steps taken in designing and implementing this mapping.