ZyXEL Communications OLT2406, Руководство пользователя

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OLT2406 User’s Guide
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C
HAPTER
9
VLAN
9.1 Overview
This chapter shows you how to configure 802.1Q tagged and port-based VLANs. The type of screen you
see here depends on the
VLAN Type you selected in the Switch Setup screen.
9.1.1 What You Can Do
• Use the VLAN Status screen ( Section 9.2 on page 110 ) to view and search all VLAN groups.
• Use the VLAN Detail screen ( Section 9.2.1 on page 110 ) to view detailed port settings and status of the
VLAN group.
• Use the VLAN Port Setting screen ( Section 9.3 on page 111 ) to configure the static VLAN (IEEE 802.1Q)
settings on a port.
• Use the Subnet Based VLANs screen ( Section 9.3.1.1 on page 114 ) to set up VLANs that allow you to
group traffic into logical VLANs based on the source IP subnet you specify.
• Use the Protocol Based VLAN screen ( Section 9.3.2.1 on page 116 ) to set up VLANs that allow you to
group traffic into logical VLANs based on the protocol you specify.
• Use the Static VLAN screen ( Section 9.4 on page 117 ) to configure and view 802.1Q VLAN parameters
for the OLT.
9.1.2 What You Need to Know
Read this section to know more about VLAN and how to configure the screens.
IEEE 802.1Q Tagged VLANs
A tagged VLAN uses an explicit tag (VLAN ID) in the MAC header to identify the VLAN membership of a
frame across bridges - they are not confined to the switch on which they were created. The VLANs can
be created statically by hand or dynamically through GVRP. The VLAN ID associates a frame with a
specific VLAN and provides the information that switches need to process the frame across the network.
A tagged frame is four bytes longer than an untagged frame and contains two bytes of TPID (Tag
Protocol Identifier, residing within the type/length field of the Ethernet frame) and two bytes of TCI (Tag
Control Information, starts after the source address field of the Ethernet frame).
The CFI (Canonical Format Indicator) is a single-bit flag, always set to zero for Ethernet switches. If a
frame received at an Ethernet port has a CFI set to 1, then that frame should not be forwarded as it is to
an untagged port. The remaining twelve bits define the VLAN ID, giving a possible maximum number of
4,096 VLANs. Note that user priority and VLAN ID are independent of each other. A frame with VID
(VLAN Identifier) of null (0) is called a priority frame, meaning that only the priority level is significant and
the default VID of the ingress port is given as the VID of the frame. Of the 4096 possible VIDs, a VID of 0 is