In Unified CM 15, phones with IPv6-only addressing cannot use EMCC; IPv4 or dual-stack addressing is required.
Checked 2026-10-02
- Vendor
- Cisco
- Product
- Cisco Unified Communications Manager
- Subsystem
- Extension Mobility Cross Cluster
- Deployment
- on-premises
- Region
- not restricted
- Release range
- 15 and SUs
- Checked
- 2026-10-02
Sources
- Feature Configuration Guide for Cisco Unified Communications Manager, Release 15 and SUs - Extension Mobility Cross Cluster — Cisco Systems · tier 2 current vendor documentation · Extension Mobility Cross Cluster Restrictions (IPv6)
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting Extension Mobility login failures in Unified CM: source note cucm-extension-mobility-troubleshooting-emcc-ipv6-only. WarmTransfer. https://warmtransfer.net/knowledge/claims/cucm-extension-mobility-troubleshooting-emcc-ipv6-only
BibTeX
@misc{warmtransfer-claim-cucm-extension-mobility-troubleshooting-emcc-ipv6-only,
title = {Troubleshooting Extension Mobility login failures in Unified CM: source note cucm-extension-mobility-troubleshooting-emcc-ipv6-only},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/cucm-extension-mobility-troubleshooting-emcc-ipv6-only},
note = {Source note cucm-extension-mobility-troubleshooting-emcc-ipv6-only, checked 2026-10-02}
}