Cheat code

QoS cheat sheet

Voice RTP is commonly EF, DSCP 46. Confirm the service parameter.
Cisco designs often mark signaling CS3. RFC 4594 assigns signaling to CS5.
A mark without a priority queue is a label.
G.711 at 20 ms is 80 kbit/s at layer 3 and 87.2 kbit/s with an 18-byte Ethernet header.
G.114 planning talk is about one-way delay around 150 ms.

Sources: RFC 4594 and the CUCM QoS service parameters for the release you run.

Sources and go deeper

Opened 2026-10. A row marked confirm has no link, because that page was not verified.

RFC. RFC 3246, Expedited Forwarding last checked 2026-10
RFC. RFC 4594, DiffServ service classes last checked 2026-10
ITU. ITU-T G.114, one-way transmission time last checked 2026-10
ITU. ITU-T G.711, pulse code modulation of voice last checked 2026-10
Cisco. Cisco Collaboration Preferred Architectures last checked 2026-10
Cisco. System Configuration Guide for CUCM, Release 15 last checked 2026-10
Community. Cisco Community, Collaboration knowledge base last checked 2026-10
Wikipedia. Differentiated services (Wikipedia) last checked 2026-10
Wikipedia. Quality of service (Wikipedia) last checked 2026-10
Cisco. Enterprise QoS SRND book. confirm. The Enterprise QoS SRND path returned HTTP 404. last checked 2026-10