Oracle SBCs allows QoS marking to apply a set of TOS/DiffServ mechanisms that enable you to provide better service for selected network. In this entry we will work in overriding the packets for SIP messages received in the external realm to be marked with 46.

First thing is creating a media policy that will help to set the new value for ToS (reference any web link for equivalent values ToS vs DSCP):

Now lets apply this new media policy created in the internal realm:

Time to test, let’s take a capture (remote) setting the Internal and External interfaces to verify that values are changed (if any doubt please check the entry for packet capture remote):

Same procedure implemented in the previous lines can be implemented to the voice packets (RTP).