User's Manual

668 802.1Q VLAN description
To use the LLDP MED network policy TLV to provision the Voice VLAN,
see “802.1ab Link Layer Discovery Protocol” (page 422).
VLAN Configuration Choices
Enhanced VLAN has two main functions
•
Enhance the current Voice VLAN by implementing the hardware VLAN
filter on the IP Phone port (SMP).
•
Use TX High Priority Queue (HPQ) and 802.1P VLAN priority to
enhance the traffic control on the IP Phone and PC network interface.
ATTENTION
VLAN filtering on the telephony port is disabled by default. If tagging is enabled
on the telephony port, you can enable VLAN filtering on the telephony port.
When VLAN filtering is enabled, packets destined for the IP Phone port are
filtered based on the MAC address and the VLAN tag.
If VLAN filtering is not enabled on the telephony port, packets destined for the IP
Phone port are filtered only on the MAC address. Filtering based on the VLAN
tag does not occur. This makes the telephony port susceptible to broadcast
storms and a Denial of Service (DOS) attack.
Enhanced Data VLAN
Enhancements for Data (PC Port) VLAN for the IP Phone include the
following
•
Data (PC Port) VLAN packet handling
— PC Port (Ingress direction)
—
PC Port (Egress direction)
• Data (PC Port) VLAN Tag Stripping
Data (PC Port) VLAN packet handling
Packets processed to and from the PC port operate as follows:
PC Port (Ingress direction)
• Data VLAN disabled—all traffic received on the PC port is switched
based on MAC address. The packets are not modified in any way.
• Data VLAN enabled—all untagged packets received on the PC port
have the 802.1Q header appended and the VLAN ID is set to the value
that was manually configured in the Data VLAN field. Any packet
arriving on the PC port that is already tagged is dropped.
PC Port (Egress direction)
Nortel Communication Server 1000
IP Phones Fundamentals
NN43001-368 05.06 30 April 2010
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