SR OS provides appropriate traffic treatment and remarking based on DSCP bits in the outer and inner header in GTP packets.
Downstream from PGW/GGSN, the DSCP bits from the outer header in a GTP packet can be mapped to a forwarding class on network ingress, which can be preserved through the chassis as the packet passes to the egress IOM. On egress, reclassification can be done based on either the inner or outer DSCP bits, depending on the configuration value of the use-ingress-l2tp-dscp option in the SLA profile.
In the upstream direction, regular ESM FC classification is used. This FC is carried through the IOM to the egress complex. In the egress complex, this FC can be used for remarking of the outer DSCP values.
DSCP and default FC values for egress GTP-C packets can be configured under sgt-qos.
It is possible to signal the subscriber’s aggregate rate or the rate of a specific scheduler in the downlink AMBR IE in both GTPv1-C and GTPv2-C. This uses the report-rate configuration of the SLA profile; the pppoe-actual-rate and rfc5515-actual-rate values are not applicable for GTP. This value can be subtracted with a value signaled during authentication to consider an average use for selective breakout.
config>subscr-mgmt>sla-prof>egress
report-rate
Other signed QoS IE values are taken from static configuration or values signaled in authentication.