QoS General notes

The following are notes regarding QoS that I consider helpful for my work.
I will update this as I learn more.

Cisco's Differentiated Services Code Point (DSCP) Values for Various Types of Traffic 

Traffic Type	Layer 2 Class of Service	Layer 3 IP Precedence	Layer 3 DSCP
Call signaling	3	3	CS3 (24)
Voice	5	5	EF (46)
Video	4	4	AF41 (34)
TelePresence	4	4	CS4 (32)

Class selector values

DSCP	Binary	Hex	Decimal	Typical application	Examples
CS0 (Default)	000 000	0x00	0
CS1	001 000	0x08	8	Scavenger	YouTube, Gaming, P2P
CS2	010 000	0x10	16	OAM	SNMP,SSH,Syslog
CS3	011 000	0x18	24	Signaling	SCCP,SIP,H.323
CS4	100 000	0x20	32	Realtime	TelePresence
CS5	101 000	0x28	40	Broadcast video	Cisco IPVS
CS6	110 000	0x30	48	Network control	EIGRP,OSPF,HSRP,IKE
CS7	111 000	0x38	56

Commonly used DSCP values

DSCP value	Hex value	Decimal value	Meaning	Drop probability	Equivalent IP precedence value
101 110	0x2e	46	Expedited forwarding (EF)	N/A	101 Critical
000 000	0x00	0	Best effort	N/A	000 - Routine
001 010	0x0a	10	AF11	Low	001 - Priority
001 100	0x0c	12	AF12	Medium	001 - Priority
001 110	0x0e	14	AF13	High	001 - Priority
010 010	0x12	18	AF21	Low	010 - Immediate
010 100	0x14	20	AF22	Medium	010 - Immediate
010 110	0x16	22	AF23	High	010 - Immediate
011 010	0x1a	26	AF31	Low	011 - Flash
011 100	0x1c	28	AF32	Medium	011 - Flash
011 110	0x1e	30	AF33	High	011 - Flash
100 010	0x22	34	AF41	Low	100 - Flash override
100 100	0x24	36	AF42	Medium	100 - Flash override
100 110	0x26	38	AF43	High	100 - Flash override

Cisco switch COS to DSCP fix
because EF (DSCP46) -> COS 5
but COS = 5 -> DSCP CS5 (40)
mls qos map cos-dscp 0 8 16 24 32 46 48 56