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Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
OL-23826-09
Chapter 24 Configuring QoS
Understanding QoS
This display shows the available classification options:
Router(config-cmap)# match ip dscp ?
<0-63> Differentiated services codepoint value
af11 Match packets with AF11 dscp (001010)
af12 Match packets with AF12 dscp (001100)
af13 Match packets with AF13 dscp (001110)
af21 Match packets with AF21 dscp (010010)
af22 Match packets with AF22 dscp (010100)
af23 Match packets with AF23 dscp (010110)
af31 Match packets with AF31 dscp (011010)
af32 Match packets with AF32 dscp (011100)
af33 Match packets with AF33 dscp (011110)
af41 Match packets with AF41 dscp (100010)
af42 Match packets with AF42 dscp (100100)
af43 Match packets with AF43 dscp (100110)
cs1 Match packets with CS1(precedence 1) dscp (001000)
cs2 Match packets with CS2(precedence 2) dscp (010000)
cs3 Match packets with CS3(precedence 3) dscp (011000)
cs4 Match packets with CS4(precedence 4) dscp (100000)
cs5 Match packets with CS5(precedence 5) dscp (101000)
cs6 Match packets with CS6(precedence 6) dscp (110000)
cs7 Match packets with CS7(precedence 7) dscp (111000)
default Match packets with default dscp (000000)
ef Match packets with EF dscp (101110)
Note For more information on DSCP prioritization, see RFC-2597 (AF per-hop behavior), RFC-2598 (EF), or
RFC-2475 (DSCP).
Classification Comparisons
Table 24-1 shows suggested IP DSCP, IP precedence, and CoS values for typical traffic types.
Table 24-1 Typical Traffic Classifications
Traffic Type
DSCP
per-hop
DSCP
(decimal)
IP
Precedence CoS
Voice-bearer—traffic in a priority queue or the queue with the
highest service weight and lowest drop priority.
EF 46 5 5
Voice control—signalling traffic, related to call setup, from a
voice gateway or a voice application server.
AF31 26 3 3
Video conferencing—in most networks, video conferencing
over IP has similar loss, delay, and delay variation requirements
as voice over IP traffic.
AF41 34 4 4
Streaming video—relatively high bandwidth applications with a
high tolerance for loss, delay, and delay variation. Usually
considered more important than regular background
applications such as e-mail and web browsing.
AF13 14 1 1
Mission critical date (gold data)—delay-sensitive applications
critical to the operation of an enterprise.
• Level 1
• Level 2
• Level 3
AF21
AF22
AF23
18
20
22
2
2
2
2
2
2