Registration Policy for TCP Header Flags

Document Type Expired Internet-Draft (individual)
Author Mirja K├╝hlewind 
Last updated 2020-05-20 (latest revision 2019-11-17)
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RFC2780 specifies the registration policy for reserved TCP header flags as Standards Action. RFC3168 created an IANA registry for these header flags and registered bit 8 (CWR) and 9 (ECE). This draft changes the registration policy of the registration to IETF Review as usually new TCP mechanisms that could use the remaining reserved flags will be first specified as experimental. Not noting any of those experiments in the registry would undermine the purpose of having a registry. However, care must be taken, as only a few reserved flags are left and if a new (experimental) mechanism sees deployment in the Internet, the flag cannot be unassigned anymore or used for something else.


Mirja K├╝hlewind (

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