Dell Wyse ThinOS Version 8.5 Hotfix INI Reference Guide

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TOS priority settings for TosDSCP INI

Routers treat network packets differently based on priority of the TOS tag in the IP header.

IP header has a 1-byte field called TOS—Type of Service.

IP precedence is older than DSCP. DSCP is compatible with IP Precedence.

Table 1. TOS priority settingsTOS priority settings
	Bit7	Bit6	Bit5	Bit4	Bit3	Bit2	Bit1	Bit0
IP precedence	IP precedence
DSCP	DSCP
DSCP	Class Selector			Drop Precedence

CS1 Dscp (001 000) match packets with precedence 1 (Low)

CS2 Dscp (010 000) match packets with precedence 2

CS3 Dscp (011 000) match packets with precedence 3

CS4 Dscp (100 000) match packets with precedence 4

CS5 Dscp (101 000) match packets with precedence 5

CS6 Dscp (110 000) match packets with precedence 6

CS7 Dscp (111 000) match packets with precedence 7 (High)

Table 2. TOS priority settingsTOS priority settings
IP precedence(3 bits)			DSCP ( 6 bits)
Name	Value	bits	Per-Hop behavior	ClassSelector	DropPrecedence	Code point Name	DSCP Bits(decimal)
Name	Value	bits	Per-Hop behavior	ClassSelector	DropPrecedence	Code point Name	DSCP Bits(decimal)
Routine	0	0	Default	NA	NA	Default	000 000 (0)
Priority	1	1	AF	1	1.Low	AF11	001 010 (10)
					2.Medium	AF12	001 100 (12)
					3.High	AF13	001 110 (14)
Immediate	2	10	AF	2	1.Low	AF21	010 010 (18)
					2.Medium	AF22	010 100 (20)
					3.High	AF23	010 110 (22)
Flash	3	11	AF	3	1.Low	AF31	011 010 (26)
					2.Medium	AF32	011 100 (28)
					3.High	AF33	011 110 (30)
Flash Override	4	100	AF	4	1.Low	AF41	100 010 (34)
					2.Medium	AF42	100 100 (36)
					3.High	AF43	100 110 (38)
Critical	5	101	EF	NA	NA	EF	101 110 (46)
Internetwork Control	6	110	NA	NA	NA	NA	(48-55)
Network Control	7	111	NA	NA	NA	NA	(56-63)

Table 3. TOS priority settingsTOS priority settings
IP precedence (3 bits)		DSCP ( 6 bits)
Name	Useful	Name	Useful
Routine	Try as usual	NA	NA
Priority	For data traffic	AF11	Big block data
Immediate	For data traffic	NA	NA
Flash	For Voice control data	NA	NA
Flash Override	Video streaming	NA	NA
Critical	Voice Data	EF	Interactive Voice
Internetwork Control	Reserved	NA	NA
NetworkControl		NA	NA
NetworkControl		NA	NA

NOTE:The information in this section is leveraged based on the research on web. Specific priority designs must be arranged by network architect.