Cisco SR224T Administration Guide - Page 169

VLAN Management Voice VLAN 12 • 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 system mode, it can synchronize with only VSDP capable switches in the same management VLAN. If the switch is in Layer 3 system 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: • 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. • 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. Voice VLAN QoS Voice VLAN can propagate the CoS/802.1p and DSCP settings by using LLDPMED Network policies. The LLDP-MED is set by default to response with the Voice QoS setting if an appliance sends LLDP-MED packets. MED-supported devices must send their voice traffic with the same CoS/802.1p and DSCP values, as received with the LLDP-MED response. You can disable the automatic update between Voice VLAN and LLDP-MED and use his own network policies. Working with the OUI mode, the switch can additionally configure the mapping and remarking (CoS/802.1p) of the voice traffic based on the OUI. By default, all interfaces are CoS/802.1p trusted. The switch applies the quality of service based on the CoS/802.1p value found in the voice stream. For Telephony OUI voice streams, you can override the quality of service and optionally remark the 802.1p of the voice streams by specifying the desired CoS/802.1p values and using the remarking option under Telephony OUI. Cisco Small Business 200 Series Smart Switch Administration Guide 170