Changing the Routing Engine Outbound Traffic Defaults
You can modify the default queue assignment (forwarding class) and DSCP bits used in the ToS field of packets generated by the Routing Engine. By default, the forwarding class (queue) and packet loss priority (PLP) bits are set according to the values given in Default DSCP and DSCP IPv6 Classifier.
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.
This feature is not available on Juniper Networks J Series Services Routers.
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. For more information about configuring queues and forwarding classes, see Overview of Forwarding Classes.
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 code point value of 101010:
