Add note on cachable OSCORE

draft-ietf-core-dns-over-coap.md

@@ -67,6 +67,7 @@ informative:
   RFC7942: impl-status-section
   I-D.ietf-add-dnr: dnr
   I-D.ietf-core-href: cri
+  I-D.amsuess-core-cachable-oscore: cachable-oscore
   DoC-paper: DOI.10.1145/3609423
 
 
@@ -348,6 +349,9 @@ OSCORE
 It is RECOMMENDED to carry DNS messages encrypted using OSCORE {{-oscore}} between the DoC client and the DoC server.
 The exchange of the security context is out of scope of this document.
 
+If cache retrieval of OSCORE responses is desired, consider following the guidances described in {{-cachable-oscore}}.
+These have, however, implications on message sizes and security, which you will find in that document.
+
 Mapping DoC to DoH
 ------------------
 This document provides no specification how to map between DoC and DoH, e.g., at a CoAP-HTTP-proxy,