DS Field (RFC 2474)
DS field replaces fields in IP header: IPv4 ToS, IPv6 Traffic Class
After years of confusion about TOS
Diffserv Code point (DSCP) = 6 bits
A number placed in the IP header to identify traffic class
“xxxxxx” notation
RFC 2481 (Experimental) defines use of 2 bits for Explicit Congestion Notification (ECN)