C.1 General

23.5483GPP5G System Enhancements for Edge ComputingRelease 17Stage 2TS

DNS records obtained from a DNS resolver in the network contains a time-to-live (TTL) value. This is a hint provided by the DNS resolver and can be used to determine the length of time that the record is to be cached. DNS records can be cached in the UE system wide (in OS) and/or applications. The application cache is managed on a per application basis while the system cache is common to applications. Name resolution caches in various applications also have different policies and behaviours. Some applications cache the DNS records for the length of the application session while others have a time limit. The recommendations in this TS will only work if the UE application (in case of DNS cache at the application layer) or the UE OS (in case of DNS cache shared by applications) consider indications from the UE modem layer with respect to DNS settings and DNS caching. Whether and how the UE (and application) considers the indication depends on implementation.