RFC Status Reference Notes
5513 Informational A. Farrel (1 April 2009). IANA Considerations for Three Letter Acronyms. Network Working Group. RFC 5513. https://tools.ietf.org/html/rfc5513.  This is an April Fools' Day Request for Comments.
5514 Experimental E. Vyncke (1 April 2009). IPv6 over Social Networks. Network Working Group. RFC 5514. https://tools.ietf.org/html/rfc5514.  This is an April Fools' Day Request for Comments.
5517 Informational S. HomChaudhuri; M. Foschiano (June 2009). Cisco Systems' Private VLANs: Scalable Security in a Multi-Client Environment. IETF. RFC 5517. https://tools.ietf.org/html/rfc5517.  Independent Submission.
5533 Proposed Standard E. Nordmark; M. Bagnulo (June 2009). Shim6: Level 3 Multihoming Shim Protocol for IPv6. Networking Working Group. RFC 5533. https://tools.ietf.org/html/rfc5533. 
5572 Experimental M. Blanchet; F. Parent (February 2010). IPv6 Tunnel Broker with the Tunnel Setup Protocol (TSP). ISSN 2070-1721. RFC 5572. https://tools.ietf.org/html/rfc5572.