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VLAN（Virtual Local Area Network）
3.5.2
In order to control the impacts brought by broadcast storms, user can divide VLANs into three groups,
namely VLAN1, VLAN2 and VLAN3. There are three kinds of VLANs, including data VLAN, voice VLAN and
management VLAN. Different kinds of VLANs have different messages.
802.1Q
The IEEE 802.1Q standard defines the architecture for Virtual Bridged LANs; the services provided in
Virtual Bridged LANs and the protocols and algorithms are involved in the provisions of those services.
No Quality of Service mechanisms are defined in this standard, but an important requirement for
providing QoS is included in this standard, e.g. the ability to regenerate user priority of received frames
using priority information contained in the frame and the User Priority Regeneration Table for the
reception Port.
802.1P
IEEE 802.1P standard describes important methods for providing QoS at MAC level. IEEE 802.1p is in fact
quite good. Lower priority level packets are not sent, if there are packets in queued in higher level queues.
IEEE 802.1p describes no admission control protocols. It would be possible to give Network Control
priority to all packets and the network would be easily congested.
Figure 3.7-3 VLAN parameter configuration
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4-/8-/16-/24-/32-Port SIP Internet Telephony Gateway
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