HP 6120XG HP ProCurve Series 6120 Blade Switches Advanced Traffic Management G - Page 83

Note Static Virtual LANs (VLANs) Effect of VLANs on Other Switch Features Components of Voice VLAN Operation ■ Voice VLAN(s): Configure one or more voice VLANs on the switch. Some reasons for having multiple voice VLANs include: • Employing telephones with different VLAN requirements • Better control of bandwidth usage • Segregating telephone groups used for different, exclusive purposes Where multiple voice VLANs exist on the switch, you can use routing to communicate between telephones on different voice VLANs. . ■ Tagged/Untagged VLAN Membership: If the appliances using a voice VLAN transmit tagged VLAN packets, then configure the member ports as tagged members of the VLAN. Otherwise, configure the ports as untagged members. Voice VLAN Access Security You can use port security configured on an individual port or group of ports in a voice VLAN. That is, you can allow or deny access to a phone having a particular MAC address. Refer to chapter titled "Configuring and Monitoring Port Security" in the Access Security Guide for your switch. MAC authentication is not recommended in voice VLAN applications. Effect of VLANs on Other Switch Features Spanning Tree Operation with VLANs Depending on the spanning-tree option configured on the switch, the spanning-tree feature may operate as a single instance across all ports on the switch (regardless of VLAN assignments) or multiple instance on a per-VLAN basis. For single-instance operation, this means that if redundant physical links exist between the switch and another 802.1Q device, all but one link will be blocked, regardless of whether the redundant links are in separate VLANs. In this case you can use port trunking to prevent Spanning Tree from unnecessarily blocking ports (and to improve overall network performance). For multiple- 2-57