The second byte in an IPv4 header is called the Differentiated Services Field.

Quoting RFC 2474:

2.  Terminology Used in This Document
...
   Differentiated Services Field: the IPv4 header TOS octet or the IPv6
   Traffic Class octet when interpreted in conformance with the
   definition given in this document.  Also DS field.

It's a historical accident that the ECN bits were shoehorned into this octet.

-- 
Regards
   Brian Carpenter


_______________________________________________
Ietf mailing list
Ietf@ietf.org
https://www.ietf.org/mailman/listinfo/ietf

Reply via email to