When the Local Gateway and the PSTN gateway are on the same device, Unified CM needs two trunks to it, using different SIP listening ports, so it can tell calls from Webex from calls from the PSTN and give each a different class of service.
Checked 2026-09-24
- Vendor
- Cisco
- Product
- Unified CM
- Subsystem
- trunks
- Deployment
- on-premises
- Region
- not restricted
- Release range
- current as of 2026-09-24
- Checked
- 2026-09-24
Sources
- Configure Unified CM for Webex Calling — Cisco Webex · tier 2 current vendor documentation · Configure SIP Trunk Security Profile for Trunk to Local Gateway
Cite this note
APA
WarmTransfer. (2026, September 24). Building a hybrid Unified CM and Webex Calling environment for a phased migration: source note cucm-webex-calling-hybrid-build-colocated-two-trunks. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-webex-calling-hybrid-build-colocated-two-trunks
BibTeX
@misc{warmtransfer-claim-cucm-webex-calling-hybrid-build-colocated-two-trunks,
title = {Building a hybrid Unified CM and Webex Calling environment for a phased migration: source note cucm-webex-calling-hybrid-build-colocated-two-trunks},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-webex-calling-hybrid-build-colocated-two-trunks},
note = {Source note cucm-webex-calling-hybrid-build-colocated-two-trunks, checked 2026-09-24}
}