Google Cloud’s network tiers for internet traffic. Premium (the default) keeps traffic on Google’s global network as long as possible; Standard sends it over the public internet near the region, with lower egress cost.
On the ACE: Standard lowers costs for regional services where global performance is not critical, but global load balancers with an anycast IP require the Premium tier.
Network Service Tiers is a concept that can show up on the exam. Check the full guide to see it in context.