Cisco 7800 Series Administration Manual page 52

VLAN Settings
Final Network Policy Resolution and QoS
Special VLANs
VLAN=0, VLAN=1, and VLAN=4095 are treated the same way as an untagged VLAN. Because the VLAN
is untagged, Class of Service (CoS) is not applicable.
Default QoS for SIP Mode
If there is no network policy from CDP or LLDP-MED, the default network policy is used. CoS is based on
configuration for the specific extension. It is applicable only if the manual VLAN is enabled and manual
VLAN ID is not equal to 0, 1, or 4095. Type of Service (ToS) is based on configuration for the specific
extension.
QoS Resolution for CDP
If there is a valid network policy from CDP:
• If the VLAN=0, 1, or 4095, the VLAN will not be set, or the VLAN is untagged. CoS is not applicable,
but DSCP is applicable. ToS is based on the default as previously described.
• If the VLAN > 1 and VLAN< 4095, the VLAN is set accordingly. CoS and ToS are based on the default
as previously described. DSCP is applicable.
• The phone reboots and restarts the fast start sequence.
QoS Resolution for LLDP-MED
If CoS is applicable and if CoS=0, the default is used for the specific extension as previously described. But
the value shown on L2 Priority for TLV for outgoing LLDPDU is based on the value used for extension 1. If
CoS is applicable and if CoS!= 0, CoS is used for all extensions.
If DSCP (mapped to ToS) is applicable and if DSCP=0, the default is used for the specific extension as
previously described. But the value show on DSCP for TLV for outgoing LLDPDU is based on value used
for the extension 1. If DSCP is applicable and if DSCP!= 0, DSCP is used for all extensions.
If the VLAN > 1 and VLAN < 4095, the VLAN is set accordingly. CoS and ToS are based on the default as
previously described. DSCP is applicable.
If there is a valid network policy for the voice application from LLDP-MED PDU and if the tagged flag is
set, the VLAN, L2 Priority (CoS), and DSCP (mapped to ToS) are all applicable.
If there is a valid network policy for the voice application from LLDP-MED PDU and if the tagged flag is
not set, only the DSCP (mapped to ToS) is applicable.
The Cisco IP Phone reboots and restarts the fast start sequence.
Coexistence with CDP
If both CDP and LLDP-MED are enabled, the network policy for the VLAN determines the last policy set or
changed with either one of the discovery modes. If both LLDP-MED and CDP are enabled, during startup
the phone sends both CDP and LLDP-MED PDUs at the same time.
Cisco IP Phone 7800 Series for Third-Party Call Control Administration Guide
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