# Dual-run and rollback

- Move one number you can give back.
- Keep the old route until the new path passes a scripted test.
- Rollback is a planned route, not a hope.
- Porting a carrier number is slower than changing a lab route.
- Evidence is a call, a ladder, and a user check.

Dual-run means the same business number can still be delivered the old way while you prove the new way, or that you can return it quickly. Carrier ports do not always allow an instant return. Say which kind of move you are doing before the night of the change.

A DID is translated to Webex Calling for a day, with the CUCM translation pattern saved. The test call fails caller ID. You put the old translation back and attach both INVITEs to the ticket. That is a rollback, not a defeat.

## Sources and go deeper

Independent, free, learning-only student project.

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

- Webex. [Get started with Webex Calling](https://help.webex.com/en-us/article/8jda92/Webex-Calling). last checked 2026-10
- Cisco. [System Configuration Guide for CUCM, Release 15](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/15/systemConfig/cucm_b_system-configuration-guide-15.html). last checked 2026-10
- Webex. [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway). last checked 2026-10
- Community. [Cisco Community, Collaboration knowledge base](https://community.cisco.com/t5/collaboration-knowledge-base/tkb-p/4691-docs-collaboration-voice-video). last checked 2026-10
- Wikipedia. [Voice over IP (Wikipedia)](https://en.wikipedia.org/wiki/Voice_over_IP). last checked 2026-10

Room or sheet file: ../../rooms/sources/dual-run/sources.json