3.3.2 DSCP rewriting

DSCP updating is functionality that is used to update the DSCP, which is the six highest-order bits of the TOS field in the IPv4 header or the traffic class field in the IPv6 header. The following diagram shows the format of TOS and traffic class fields.

Figure 3-3 Format of the TOS field

Figure 3-4: Format of the traffic class field

As shown, the six highest-order bits of the TOS field or traffic class field of the detected frame are updated.