Replacement of DSCP on Egress

The switch can be configured to change the DSCP in a packet before forwarding the packet. This is done with no impact on switch performance and can be configured as described in the following sections:

Replacement in ACL-Based Traffic Groups

If you are using ACL-based traffic groups, you can use the replace-dscp action modifier to replace the ingress DSCP value with the DSCP value of the egress QoS profile as listed in the following table. This action modifier functions for both IPv4 and IPv6 traffic.



If you are using ACL-based traffic groups, you must use ACL action modifiers to replace the DSCP. Traffic that meets any ACL match conditions is not subject to non-ACL-based DSCP priority replacement. For all platforms, we recommend that you use ACL-based traffic groups when configuring DSCP replacement.

Replacement in Non-ACL-Based Traffic Groups

For non-ACL-based traffic groups, you can enable or disable DSCP replacement on specific ingress ports. When DSCP replacement is enabled, the DSCP value used on egress is determined by either the QoS profile or the 802.1p priority value. The following table shows the default mappings of QoS profiles and 802.1p priority values to DSCPs.

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Default QoS Profile and 802.1p Priority Value Mapping to DiffServ Code Points

BlackDiamond X8 Series Switches, BlackDiamond 8800 Series Switches, SummitStack, and Summit Family Switches QoS Profile 802.1p Priority Value DSCP
QP1 0 0
  1 8
  2 16
  3 24
  4 32
  5 40
  6 48
QP8 7 56