Cisco warns that when network devices give a phone inconsistent VLAN configuration through CDP and LLDP-MED, the phone can reboot repeatedly as it switches between VLANs.
Checked 2026-10-02
Inconsistent configuration and behavior for network connectivity devices for CDP and LLDP-MED modes could result in an oscillating rebooting behavior for the phone due to switching to different VLANs.
- Vendor
- Cisco
- Product
- Cisco IP Phone Multiplatform Firmware
- Subsystem
- LLDP-MED
- Deployment
- multi-tenant, on-premises
- Region
- not restricted
- Release range
- current as of 2026-10-02
- Checked
- 2026-10-02
Sources
- Cisco IP Desk Phone with Multiplatform Firmware (MPP) - Administration Guide - Technical Details — Cisco Systems · tier 2 current vendor documentation · Coexistence with CDP / Final Network Policy Resolution and QoS
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-mpp-oscillating-reboot. WarmTransfer. https://warmtransfer.net/knowledge/claims/ip-phone-dhcp-vlan-troubleshooting-mpp-oscillating-reboot
BibTeX
@misc{warmtransfer-claim-ip-phone-dhcp-vlan-troubleshooting-mpp-oscillating-reboot,
title = {Troubleshooting IP phones that do not get a voice VLAN or DHCP options: source note ip-phone-dhcp-vlan-troubleshooting-mpp-oscillating-reboot},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/ip-phone-dhcp-vlan-troubleshooting-mpp-oscillating-reboot},
note = {Source note ip-phone-dhcp-vlan-troubleshooting-mpp-oscillating-reboot, checked 2026-10-02}
}