Robust Header Compression
Robust Header Compression (ROHC) is a standardized method to compress the IP, UDP, UDP-Lite, RTP, and TCP headers of Internet packets. == The need for header compression == In streaming applications, the overhead of IP, UDP, and RTP is 40 bytes for IPv4, or 60 bytes for IPv6.
Source: Wikipedia — Robust Header Compression (CC BY-SA 4.0)