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Changing the Default Queuing and Marking of Host Outbound Traffic

You can modify the default queue assignment (forwarding class) and DSCP bits used in the ToS field of host outbound traffic (packets generated by the Routing Engine).

TCP-related packets, such as BGP or LDP, use queue 3 (network control) for retransmitted traffic. Changing the defaults for Routing Engine sourced traffic does not affect transit or incoming traffic. The changes apply to all packets relating to Layer 3 and Layer 2 protocols, but not MPLS EXP bits or IEEE 802.1p bits. This feature applies to all application-level traffic such as FTP or ping operations as well.

The queue selected is global to the routing device. That is, the traffic is placed in the selected queue on all egress interfaces. In the case of a restricted interface, the Routing Engine sourced traffic flows through the restricted queue.

The queue selected must be properly configured on all interfaces.

To change the default queue and DSCP bits for Routing Engine sourced traffic, include the host-outbound-traffic statement at the [edit class-of-service] hierarchy level:

The following example places all Routing Engine sourced traffic into queue 3 (network control) with a DSCP value of 101010: