Packet Network: Type of Service

Value to store in the TOS (Type Of Service) field of the IP header of RTP packets.

The most recent usage of this field is a six-bit Differentiated Services Code Point (DSCP) and a two-bit Explicit Congestion Notification (ECN).

0 || 1 || 2 || 3 || 4 || 5	6 || 7
DSCP field	DSCP field	DSCP field	DSCP field	DSCP field	DSCP field	ECN field	ECN field

For example, if a TOS value of 144 is used, the DSCP tag will be 36 (if ECN field is not used). Some examples:

TOS Value	DSCP Value
0	0
32	8
40	10
56	14
72	18
88	22
96	24
112	28
136	34
144	36
152	38
160	40
184	46
192	48
224	56

DSCP <=> IP Precedence Conversion Table

DSCP Name	DS Field Value (Dec)	IP Precedence (Description)
CS0	0	0: Best Effort
CS1, AF11-13	8,10,12,14	1: Priority
CS2, AF21-23	16,18,20,22	2: Immediate
CS3, AF31-33	24,26,28,30	3: Flash - mainly used for voice signaling
CS4, AF41-43	32,34,36,38	4: Flash Override
CS5,EF	40,46	5: Critical - mainly used for voice RTP
CS6	48	6: Internetwork Control
CS7	56	7: Network Control

Wikipedia link: Type of Service