Amplification attacks using resource directory?

[emanjon]

Comment from Mohit Sethi to consider if there are any amplification attacks using the resource directory

[ms-s]

Also if there any attacks when using broker: https://datatracker.ietf.org/doc/html/draft-ietf-core-coap-pubsub-10. Or can I make the victim part of a group: https://datatracker.ietf.org/doc/html/rfc7390.