What is an effect of using ingress filtering to prevent spoofed addresses on a network design?

DSCP remarking to Scavenger class is a QoS mechanism for deprioritizing unwanted traffic, not a function of ingress filtering, which performs source address validation and dropping rather than any remarking action.

Ingress filtering - implemented via Unicast Reverse Path Forwarding (uRPF) or inbound ACLs - checks that a packet's source address is reachable through the interface it arrived on, discarding packets with spoofed source IPs before they traverse the network and preventing attackers from hiding behind forged addresses during DDoS attacks.

Filtering RFC 1918 private addresses is a specific form of bogon filtering and represents only one narrow use case, not the defining or primary effect of ingress filtering as an anti-spoofing control.

Remarking bogon traffic with DSCP bulk is a QoS policy decision unrelated to ingress filtering, which drops spoofed packets outright rather than classifying or queuing them.