3.5.2 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.

You can also use DSCP updating to update the DSCP of a frame that exceeds the minimum monitoring bandwidth on instruction from the bandwidth monitoring functionality. For example, you can set the DSCP value to 0 for frames that exceed the minimum monitoring bandwidth.

For handling of non-compliant frames when DSCP updating and minimum bandwidth monitoring are specified at the same time, the penalty operation specified for non-compliance has priority.