DSCP / QoS Converter
Translate a QoS marking between DSCP (EF, AFxy, CSx), the ToS/DS byte in hex and binary, IP Precedence and 802.1p CoS, with the meaning of each class (PHB). Type a number 0–63, a name or the byte 0–255. Everything in your browser.
Class meaning (PHB)
—
DS / ToS byte breakdown
| Bits | Field | Value |
|---|
DSCP bits (7–2) ECN bits (1–0, here 0)
Common QoS markings
| Name | DSCP | ToS hex | Prec. | CoS |
|---|
How it is calculated · DSCP, ToS, IP Precedence and CoS
1. The DSCP is the top
6 bits of the differentiated services (DS) byte,
formerly the ToS field. It ranges from 0 to 63.
2. The full byte is
ToS = DSCP × 4 (DSCP << 2): the DSCP
occupies bits 7–2 and the low 2 bits (1–0) are
ECN, here set to 0.
3. The IP Precedence and the
suggested 802.1p CoS are the top 3 bits:
DSCP ÷ 8 (DSCP >> 3),
from 0 to 7.
4. Names: CSx = x·8,
AFxy = 8·x + 2·y (class x, drop
precedence y) and EF = 46 for low-latency voice.
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