VLAN Configuration Guide, Cisco IOS XE 17.15.x (Catalyst 9300 Switches) - Configuring Voice VLANs

Publisher

Cisco Systems

URL

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/software/release/17-15/configuration_guide/vlan/b_1715_vlan_9300_cg/configuring_voice_vlans.html

Published

2024-08-14

Updated

unknown

Accessed

2026-09-24

HTTP status

200

License

Cisco copyright; all rights reserved; no-redistribution; short excerpts and locators only

Source notes citing this source

• 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. in context
• The Catalyst 9300 voice VLAN guide warns that enabling IEEE 802.1X on an access port can cost the phone up to 30 seconds of connectivity to the switch. in context
• On Catalyst 9300, switchport priority extend trust tells the phone's access (PC) port to trust the priority received from the attached PC, and switchport priority extend cos <0-7> makes the phone override it, with a default of cos 0. in context
• Per the Catalyst 9300 guide, untagged traffic from a device attached to the Cisco IP phone's PC port passes through the phone unchanged, whatever the trust state of the phone's access port. in context
• On Catalyst 9300 with port security on a voice VLAN port, the maximum secure addresses must be set to two plus the maximum allowed on the access VLAN, because the phone needs up to two MAC addresses. in context
• On Catalyst 9300 switches running IOS XE 17.15.x, voice VLAN can be configured only on access ports, not on trunk ports. in context
• On Catalyst 9300 (IOS XE 17.15.x), CDP must be enabled on the port connected to a Cisco IP phone for the switch to send it the voice VLAN configuration, and CDP is globally enabled by default on all interfaces. in context
• The Catalyst 9300 voice VLAN guide says voice traffic carries a default Layer 3 IP precedence of 5 and voice control traffic a default of 3. in context
• On Catalyst 9300, switchport voice vlan dot1p makes the switch accept voice and data 802.1p priority frames tagged with VLAN ID 0 (the native VLAN). in context
• On Catalyst 9300, switchport voice vlan untagged tells the phone to send untagged voice traffic, while switchport voice vlan none lets the phone use its own configuration to send untagged voice traffic. in context
• On Catalyst 9300, switchport voice vlan <vlan-id> tells the phone to send all voice traffic tagged in that VLAN, with a default IEEE 802.1Q priority of 5. in context
• On Catalyst 9300 (IOS XE 17.15.x), configuring a voice VLAN on a port automatically enables PortFast on it. in context
• The Catalyst 9300 (IOS XE 17.15.x) guide says to enable QoS with the trust device cisco-phone interface command before enabling voice VLAN, unless auto-QoS is used, which configures these settings automatically. in context
• On Catalyst 9300 (IOS XE 17.15.x) the voice VLAN must be present and active on the switch for the IP phone to communicate on it. in context

Cite this source record

APA

WarmTransfer. (2024, August 14). VLAN Configuration Guide, Cisco IOS XE 17.15.x (Catalyst 9300 Switches) - Configuring Voice VLANs. WarmTransfer. https://warmtransfer.net/knowledge/sources/cisco-cat9300-1715-voice-vlans

BibTeX

@misc{warmtransfer-cisco-cat9300-1715-voice-vlans,
  title  = {VLAN Configuration Guide, Cisco IOS XE 17.15.x (Catalyst 9300 Switches) - Configuring Voice VLANs},
  author = {{WarmTransfer}},
  year   = {2024},
  url    = {https://warmtransfer.net/knowledge/sources/cisco-cat9300-1715-voice-vlans},
  note   = {Cisco Systems, accessed 2026-09-24}
}