4 位 Priority 字段说明遵循的是已被 RFC 2460(Solaris 8 实现 RFC 2460 规范) 淘汰了的 RFC 1883 规范。结果,Priority 字段已被 8 位 Traffic Class 字段所取代。Priority 一节应被以下的 Traffic Class 一节所取代。
Originating nodes and forwarding routers can use the 8-bit Traffic Class field in the IPv6 header to identify and distinguish between different classes or priorities of IPv6 packets.
The following general requirements apply to the Traffic Class field.
The service interface to the IPv6 service within a node must provide a means for an upper-layer protocol to supply the value of the Traffic Class bits in packets originated by that upper-layer protocol. The default value must be zero for all 8 bits.
Nodes that support a specific use of some or all of the Traffic Class bits can change the value of those bits in packets that they originate, forward, or receive, as required for that specific use. Nodes should ignore and leave unchanged any bits of the Traffic Class field for which they do not support a specific use.