A Cisco phone on an access port where neither CDP nor LLDP-MED delivers a voice VLAN, and with no manual VLAN set, sends untagged traffic. It therefore lands in the port's access (data) VLAN and takes its DHCP lease and options from the data scope.
inferred · Checked 2026-10-02
- Vendor
- Cisco
- Product
- Cisco IP Phone Multiplatform Firmware
- Subsystem
- voice VLAN
- Deployment
- multi-tenant, on-premises
- Region
- not restricted
- Release range
- current as of 2026-10-02
- Status
- inferred
- Checked
- 2026-10-02
Sources
- Cisco IP Desk Phone with Multiplatform Firmware (MPP) - Administration Guide - Technical Details — Cisco Systems · tier 2 current vendor documentation · Final Network Policy Resolution and QoS (combined with cisco-cat9300-1718-voice-vlans, Prerequisites for Voice VLANs)
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting IP phones that do not get a voice VLAN or DHCP options: source note ip-phone-dhcp-vlan-troubleshooting-infer-untagged-data-vlan. WarmTransfer. https://warmtransfer.net/knowledge/claims/ip-phone-dhcp-vlan-troubleshooting-infer-untagged-data-vlan
BibTeX
@misc{warmtransfer-claim-ip-phone-dhcp-vlan-troubleshooting-infer-untagged-data-vlan,
title = {Troubleshooting IP phones that do not get a voice VLAN or DHCP options: source note ip-phone-dhcp-vlan-troubleshooting-infer-untagged-data-vlan},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/ip-phone-dhcp-vlan-troubleshooting-infer-untagged-data-vlan},
note = {Source note ip-phone-dhcp-vlan-troubleshooting-infer-untagged-data-vlan, checked 2026-10-02}
}