5.2. Generating and Using Incomplete Responses

When following the procedure in Section 4.2, recursive resolvers MAY terminate the procedure early and produce a reply that omits some of the associated RRsets. This is REQUIRED when the chain length limit is reached (Step 1 in Section 4.2) but might also be appropriate when the maximum response size is reached or when responding before fully chasing dependencies would improve performance. When omitting certain RRsets, recursive resolvers SHOULD prioritize information for smaller-SvcPriority records.

As discussed in Section 3, clients MUST be able to fetch additional information that is required to use a SVCB record, if it is not included in the initial response. As a performance optimization, if some of the SVCB records in the response can be used without requiring additional DNS queries, the client MAY prefer those records, regardless of their priorities.