Relays SHOULD aggregate and propagate filters upstream on subscriptions, especially namespace subscriptions, to conserve and protect their resources from excessive load. They MAY also impose limits on the number of publishers in a namespace, by rejecting or closing namespace subscriptions with the error NAMESPACE_TOO_LARGE. Relays MAY likewise limit the load imposed by subscribers, by rejecting or closing namespace subscriptions with CONFLICTING_FILTERS if too many disjoint filters are requested on downstream subscriptions across a large number of subscribers, or with PREFIX_OVERLAP if different subscribers force an aggregated upstream subscription to overlap.
§7.5.
Relay Resource Protection in Large Namespaces
This is one section of the MoQT specification, rendered per-section for quick reference and citation. The authoritative text is draft-ietf-moq-transport-22 at the IETF.