On a Catalyst 9300 the voice VLAN is set per access port with switchport voice vlan vlan-id, CDP must be enabled on the port to send that configuration to the phone, and show interfaces interface-id switchport displays it.

Checked 2026-09-24

You must enable CDP on the device port connected to the Cisco IP Phone to send the configuration to the phone
Vendor
Cisco
Product
Catalyst 9300 (IOS XE)
Subsystem
voice VLAN
Deployment
on-premises
Region
not restricted
Release range
IOS XE 17.15.x
Checked
2026-09-24

Sources

Cite this note

APA

WarmTransfer. (2026, September 24). Troubleshooting Cisco IP phone registration: source note cisco-phone-registration-troubleshooting-sw-voice-vlan. WarmTransfer. https://warmtransfer.net/knowledge/claims/cisco-phone-registration-troubleshooting-sw-voice-vlan

BibTeX

@misc{warmtransfer-claim-cisco-phone-registration-troubleshooting-sw-voice-vlan,
  title  = {Troubleshooting Cisco IP phone registration: source note cisco-phone-registration-troubleshooting-sw-voice-vlan},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/cisco-phone-registration-troubleshooting-sw-voice-vlan},
  note   = {Source note cisco-phone-registration-troubleshooting-sw-voice-vlan, checked 2026-09-24}
}

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