CoAP is being standardised as an application level REST-based protocol. A single CoAP message is typically encapsulated and transmitted using UDP. This draft examines the requirements and possible solutions for conveying CoAP packets to end points over alternative transports to UDP. UDP remains the optimal solution for CoAP use in IP-based constrained environments and nodes. However the need for M2M communication using non-IP networks, improved transport level end-to-end reliability and security, NAT and firewall traversal issues, and mechanisms possibly incurring a lower overhead to CoAP/ HTTP translation gateways provide compelling motivation for understanding how CoAP can operate in various other environments.