VLAN Management
Voice VLAN
Cisco Small Business 200 1.1 Series Smart Switch Administration Guide
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It synchronizes the voice VLAN-related parameters with other Auto Voice
VLAN-enabled switches, using Voice Service Discovery Protocol (VSDP).
The switch always configures itself with the voice VLAN from the highest
priority source it is aware of. The priority is based on the source type and
MAC address of the source providing the voice VLAN information. Source
type priority from high to low are static VLAN configuration, CDP
advertisement, and default configuration based on changed default VLAN,
and default voice VLAN. A numeric low MAC address is of higher priority
than a numeric high MAC address.
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It maintains the voice VLAN until a new voice VLAN from a higher priority
source is discovered or until the Auto Voice VLAN is restarted by the
administrator. When restarted, the switch resets the voice VLAN to the
default voice VLAN and restarts the Auto Voice VLAN discovery.
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When a new voice VLAN is configured/discovered, the switch automatically
creates it, and replaces all the port memberships of the existing voice VLAN
to the new voice VLAN. This may interrupt or terminate existing voice
sessions, which is expected when network topology is altered.
NOTE
If the switch is in Layer 2 mode, it can synchronize with only VSDP
capable switches in the same management VLAN. If the switch is in layer 3
mode, it can synchronize with VSDP capable switches that are in the
directly-connected IP subnets configured at the switch.
Auto Smartport works with CDP/LLDP to maintain the port memberships of the
voice VLAN when voice end-points are detected from the ports:
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When CDP and LLDP are enabled, the switch sends out CDP and LLDP
packets periodically to advertise the voice VLAN to the voice endpoints to
use.
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When a device attaching to a port advertises itself as a voice endpoint
through CDP and/or LLDP, the Auto Smartport automatically adds the port
to the voice VLAN by applying the corresponding Smartport macro to the
port (if there is no other devices from the port advertising a conflicting or
superior capability). If a device advertises itself as a phone, the default
Smartport macro is phone. If a device advertises itself as a phone and host
or phone and bridge, the default Smartport macro is phone+desktop.