SonicOS 7 Profile Objects
DSCP Marking
DSCP (Differentiated Services Code Point) marking uses 6-bits of the 8-bit ToS field in the IP Header to provide up to 64 classes (or code points) for traffic. Since DSCP is a layer 3 marking method, there is no concern about compatibility as there is with 802.1p marking. Devices that do not support DSCP will simply ignore the tags, or at worst, they will reset the tag value to 0.
DSCP Marking: IP packet
The above image depicts an IP packet, with a close-up on the ToS portion of the header. The ToS bits were originally used for Precedence and ToS (delay, throughput, reliability, and cost) settings, but were later repurposed by RFC2474 for the more versatile DSCP settings.
The below table displays the commonly used code points, as well as their mapping to the legacy Precedence and ToS settings.
DSCP | DSCP Description | Legacy IP Precedence | Legacy IP ToS (D, T, R) |
---|---|---|---|
0 | Best effort | 0 (Routine – 000) | - |
8 | Class 1 | 1 (Priority – 001) | - |
10 | Class 1, gold (AF11) | 1 (Priority – 001) | T |
12 | Class 1, silver (AF12) | 1 (Priority – 001) | D |
14 | Class 1, bronze (AF13) | 1 (Priority – 001) | D, T |
16 | Class 2 | 2 (Immediate – 010) | - |
18 | Class 2, gold (AF21) | 2 (Immediate – 010) | T |
20 | Class 2, silver (AF22) | 2 (Immediate – 010) | D |
22 | Class 2, bronze (AF23) | 2 (Immediate – 010) | D, T |
24 | Class 3 | 3 (Flash – 011) | - |
26 | Class 3, gold (AF31) | 3 (Flash – 011) | T |
27 | Class 3, silver (AF32) | 3 (Flash – 011) | D |
30 | Class 3, bronze (AF33) | 3 (Flash – 011) | D, T |
32 | Class 4 | 4 (Flash Override – 100) | - |
34 | Class 4, gold (AF41) | 4 (Flash Override – 100) | T |
36 | Class 4, silver (AF42) | 4 (Flash Override – 100) | D |
38 | Class 4, bronze (AF43) | 4 (Flash Override – 100) | D, T |
40 | Express forwarding | 5 (CRITIC/ECP – 101) | - |
46 | Expedited forwarding (EF) | 5 (CRITIC/ECP – 101) | D, T |
48 | Control | 6 (Internet Control – 110) | - |
56 | Control | 7 (Network Control – 111) | - |
ECP: Elliptic Curve Group
DSCP marking can be performed on traffic to/from any interface and to/from any zone type, without exception. DSCP marking is controlled by Access Rules, from the QoS view, and can be used in conjunction with 802.1p marking, as well as with SonicOS’s internal bandwidth management.
- DSCP Marking and Mixed VPN Traffic
- Configure for 802.1p CoS 4 – Controlled load
- QoS Mapping
- Managing QoS Marking
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