RFCs 8321 and RFC 8889 describe the "alternate marking method" that uses a few bits in a protocol header to enable various types of network measurement. These documents are Experimental, which is complicating the effort to cite them in Proposed Standards that instantiate these techniques in a particular protocol. The consensus in the IPPM working groups is that these techniques have been widely implemented and deployed, and are therefore mature enough to progress to Proposed Standard. See the thread that starts here: https://mailarchive.ietf.org/arch/msg/ippm/U-gy4T5XxfxIkdmMK-hWaeRKHwY/ Based on this input, I believe the documents meet the requirements for Proposed Standard in RFCs 2026 and 6410. They have no known errata.