Transitioning from Unified CM to Webex Calling — Deployment Guide

Publisher

Cisco Systems, Inc. (CTG TME)

URL

https://www.cisco.com/c/dam/en/us/td/docs/solutions/PA/mcp/DEPLOYMENT_CALLING_Unified_CM_to_Webex_Calling.pdf

Published

2025-12

Updated

unknown

Accessed

2026-09-04

HTTP status

200

License

Cisco proprietary documentation, all rights reserved; no-redistribution; short excerpts and locators only

Claims citing this source

• An estate standardised on Cisco 6800 series phones running Enterprise firmware faces hardware replacement rather than firmware conversion, so a migration business case built only on licence costs will understate the true cost. inference in context
• Webex App is the only soft client supported by Webex Calling, whereas Unified CM supports both Webex App and Jabber. fact in context
• Cisco 6800 series IP phones cannot be upgraded from Enterprise firmware to Multiplatform firmware, so a 6800 running Enterprise firmware on Unified CM must be replaced rather than converted. fact in context
• Cisco 7800 and 8800 series phones must be converted from Enterprise firmware to Multiplatform firmware before they can register to Webex Calling. fact in context
• Older 8800 series units with hardware version VID 14 or earlier will register with Webex Calling but may show performance issues arising from hardware limitations. fact in context
• The 8845, 8865 and 8865NR have reached end of sale and Cisco does not recommend migrating them to Webex Calling. fact in context
• The Cisco 9800 series runs PhoneOS, which supports registration to both Unified CM and Webex Calling, so 9800 phones transition without a firmware conversion. fact in context
• The same guide separately lists the 8845, 8865 and 8875 as personal video phones that are supported with Webex Calling. fact in context
• The 8845 and 8865 personal video phones are end-of-sale and not recommended for migration, even though they remain supported with Webex Calling. fact in context
• Only the Cisco 6800, 7800, 8800 and 9800 desk phone series are supported with Webex Calling, which is a subset of the phones supported on Unified CM. fact in context
• Supported Local Gateway hardware includes Cisco IOS XE ISR 1100 and 4000 series routers, Catalyst 8200 and 8300 series, Catalyst 8000V Edge Software, and certified third-party session border controllers; the Local Gateway may be deployed on premises or hosted by a partner. fact in context
• Cisco defines 2 migration approaches: a flash-cut in which all users and devices move in 1 window after which the on-premises estate can be decommissioned, and a phased approach in which groups move over an extended period. fact in context
• The phased architecture is described as Phase 0 with Unified CM only on premises, Phase 1 as a hybrid coexistence state with dual call control split between Unified CM and Webex Calling, and Phase 2 as fully cloud with all users on Webex Calling. fact in context
• Control Hub includes a device eligibility tool named Migrate Your Phone to Webex Calling, and selecting the Generate device license only option performs an eligibility check without adding the devices. fact in context
• Cisco explicitly allows for organisations remaining indefinitely in the Phase 1 dual call control coexistence state with no plan to complete the transition to cloud calling. fact in context
• Cisco lists business reasons to keep call control on premises: phone models unsupported by Webex Calling, numerous or complex integrations without cloud equivalents, complex dial plans or granular classes of service, unreliable internet access, strict data privacy or ownership rules, on-premises or in-country call recording mandates, third-party integrations without a Webex Calling alternative, and contact-centre integrations not yet moving to cloud. fact in context
• Cisco recommends moving users onto Webex App while they are still registered to Unified CM calling, and only then cutting them over to Webex Calling. fact in context
• The target architecture adds Webex Calling as the cloud call service, Cisco Directory Connector or the Entra ID wizard application for identity synchronisation, a Local Gateway for PSTN access and Unified CM interoperation, and a Survivability Gateway for fallback calling during outages; Cisco Calling Plan and Cloud Connect require no on-premises equipment. fact in context
• The recommended project lifecycle has 3 phases distinct from the architecture phases: Pre-Migration covering organisation setup, licensing, user provisioning, network readiness and software upgrades; Migration Prep covering feature definition, Unified CM data extraction, client and phone version planning, testing and pilot; and Migration Rollout and Decommission covering adoption, user and device migration, feature migration and decommissioning the on-premises estate. fact in context
• Phones returning Unknown from the eligibility check are resolved either by reading the product ID and version ID from the physical phone label, or by running a third-party IP Phone Readiness Tool against Unified CM. fact in context
• Cisco's recommended network targets for good voice quality over the internet are 1-way latency below 100 milliseconds, jitter below 10 milliseconds, and packet loss of 0.5 percent or less. fact in context
• Cisco states that the IP Phone Readiness Tool it points to is not an official Cisco tool and is not supported by Cisco TAC, carrying best-effort support only while being free to use. fact in context

Cite this source record

APA

WarmTransfer. (n.d.). Transitioning from Unified CM to Webex Calling — Deployment Guide. WarmTransfer. https://warmtransfer.net/knowledge/sources/cisco-pdf-transitioning-ucm-to-webex-calling

BibTeX

@misc{warmtransfer-cisco-pdf-transitioning-ucm-to-webex-calling,
  title  = {Transitioning from Unified CM to Webex Calling — Deployment Guide},
  author = {{WarmTransfer}},
  year   = {2025},
  url    = {https://warmtransfer.net/knowledge/sources/cisco-pdf-transitioning-ucm-to-webex-calling},
  note   = {Cisco Systems, Inc. (CTG TME), accessed 2026-09-04}
}