UC LabFree University

T5 · T5-R03

Locations and call admission control

ExportSVGPNGHTMLSheet

Learn it in 5 minutes

  • A CUCM location names a bandwidth budget between sites.
  • CAC refuses a call. QoS schedules a call that was allowed.
  • Audio and video budgets are separate in current CUCM designs.
  • Refused calls show a cause, not silence.
  • Locations do not mark DSCP.
ExportSVGPNGHTMLSheet

Visual

Locations and call admission control diagram
ExportSVGPNGHTMLSheet

What is going on

If you set the location bandwidth below the real queue, CUCM blocks calls the WAN could have carried. If you set it far above the queue, CUCM admits calls the queue will damage. The two numbers should be designed together.

Confirm before relying. Confirm video bandwidth defaults in your CUCM version.

ExportSVGPNGHTMLSheet

Worked example

Site A to site B is 1 Mbit/s for voice in CUCM and 512 kbit/s in the priority queue. The sixth G.711 call is admitted and then sounds broken. Align the location with the queue, or the reverse, on purpose.

ExportSVGPNGHTMLSheet

Quiz

1. CUCM locations mark RTP as EF.

ExportSVGPNGHTMLSheet

Ecosystem

Sister pieces sit on the ecosystem page: the glossary, the mind map, the integration map, and the sibling labs.

  • Location — A CUCM bandwidth domain for admission control.
  • CAC — Call admission control, the decision to allow a call.

Config. Record location bandwidth and the WAN policy in the same note.

Troubleshooting. A reorder from CUCM with no SIP error on the carrier is often CAC or a CSS, not the PSTN.

Bridge. Webex Calling does not use CUCM locations for cloud media. Keep the words apart.

Mind map, sister technologies, and future hooks live on the ecosystem page.

ExportSVGPNGHTMLSheet

Sources

Product screens move. Confirm the guide for your release before you change a live system.

ExportSVGPNGHTMLSheet

Sources and go deeper

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

sources.json Markdown