Differentiated services code point (DSCP), forwarding class (FC), and IEEE 802.1p values can be specified for use by protocol packets generated by the node. This enables prioritization or deprioritization of supported protocols (as required).
DSCP marking for internally generated control and management traffic should be used for a specified application. This can be configured per routing instance. For example, OSPF packets can carry a different DSCP marking for the base instance than for a VPRN service. ARP and IS-IS are not IP protocols, so only 802.1p values can be configured.
The DSCP value can be set per application. When an application is configured to use a specified DSCP value and an FC, the 802.1p and MPLS EXP bits are marked in accordance with the network (default 802.1p value of 7) or access (default 802.1p value of 0) egress policy as it applies to the logical interface the packet is egressing.
Configuring self-generated QoS is supported in the base router and VPRN service contexts.
The default values for self-generated traffic on network interfaces are the following:
routing protocols (for example, OSPF and BGP)
FC - Network Control (NC)
DSCP value - NC1 (not applicable for ARP and IS-IS)
802.1p value - according to the egress QoS policy (7 by default)
management protocols (for example, SSH and SNMP)
FC - Network Control (NC)
DSCP value - AF41
802.1p value - according to the egress QoS policy (7 by default)
ICMP echo requests (type 8) and ICMPv6 echo requests (type 128) initiated from the router use the DSCP value that is specified in the sgt-qos command. The FC value is NC by default, or the value that is specified in the ping command parameter fc fc-name.
Configurable values for BFD are not supported.
On access SAP egress and access port egress, when remarking is not enabled, the dot1p value for all IP packets generated by the node is set to zero. To enable dot1p marking, remarking must be enabled.