DSCP & QoS reference
Every DSCP code point with its ToS byte, IP precedence, CoS and Wi-Fi access category, what it is meant for, and ready-made capture filters and marking commands. Type a name, a value or a ToS byte to convert it.
Examples
ToS byte, bit by bit
Click a DSCP bit to flip it. The top three bits are the class (old IP precedence, and the default CoS); for AF code points the next two give the drop precedence. The last two bits belong to ECN, not DSCP.
Details
Filters and marking
All standard code points
| Name | DSCP | ToS byte | Prec. / CoS | Wi-Fi | Typical use |
|---|---|---|---|---|---|
| 0 | 0 (0x00) | 0 | Best effort (UP 0) | Best effort, the default (also called DF) | |
| 1 | 4 (0x04) | 0 | Background (UP 1) | Lower effort: background that yields to everything (RFC 8622) | |
| 8 | 32 (0x20) | 1 | Background (UP 1) | Low-priority data, "scavenger" (backups, updates) | |
| 10 | 40 (0x28) | 1 | Best effort (UP 0) | High-throughput data (bulk transfers) | |
| 12 | 48 (0x30) | 1 | Best effort (UP 0) | High-throughput data, medium drop | |
| 14 | 56 (0x38) | 1 | Best effort (UP 0) | High-throughput data, high drop | |
| 16 | 64 (0x40) | 2 | Best effort (UP 0) | Operations and management (SNMP, SSH, syslog) | |
| 18 | 72 (0x48) | 2 | Best effort (UP 3) | Low-latency data (transactions, interactive apps) | |
| 20 | 80 (0x50) | 2 | Best effort (UP 3) | Low-latency data, medium drop | |
| 22 | 88 (0x58) | 2 | Best effort (UP 3) | Low-latency data, high drop | |
| 24 | 96 (0x60) | 3 | Video (UP 4) | Broadcast video (RFC 4594); call signalling in Cisco's QoS model | |
| 26 | 104 (0x68) | 3 | Video (UP 4) | Multimedia streaming (video on demand) | |
| 28 | 112 (0x70) | 3 | Video (UP 4) | Multimedia streaming, medium drop | |
| 30 | 120 (0x78) | 3 | Video (UP 4) | Multimedia streaming, high drop | |
| 32 | 128 (0x80) | 4 | Video (UP 4) | Real-time interactive (gaming, telepresence) | |
| 34 | 136 (0x88) | 4 | Video (UP 4) | Multimedia conferencing (video calls) | |
| 36 | 144 (0x90) | 4 | Video (UP 4) | Multimedia conferencing, medium drop | |
| 38 | 152 (0x98) | 4 | Video (UP 4) | Multimedia conferencing, high drop | |
| 40 | 160 (0xa0) | 5 | Video (UP 5) | Signalling (SIP, H.323) per RFC 4594; broadcast video in Cisco's model | |
| 44 | 176 (0xb0) | 5 | Voice (UP 6) | Voice-admit: admission-controlled voice (RFC 5865) | |
| 46 | 184 (0xb8) | 5 | Voice (UP 6) | Telephony: voice media (RTP) | |
| 48 | 192 (0xc0) | 6 | Voice (UP 7) | Network control (OSPF, BGP, HSRP/VRRP) | |
| 56 | 224 (0xe0) | 7 | — | Reserved for link-layer and future use; rarely seen |
ToS byte = DSCP × 4: the low two bits are ECN. CoS is the default switch mapping (the top three DSCP bits, the old IP precedence). Wi-Fi follows RFC 8325. Cisco's 12-class model swaps CS3 and CS5 compared with RFC 4594. Markings are usually reset at the trust boundary, so check what each hop trusts.