XGS-4728F User’s Guide
95
C
H A P T E R
9
VLAN
The type of screen you see here depends on the VLAN Type you selected in the
Switch Setup screen. This chapter shows you how to configure 802.1Q tagged
and port-based VLANs.
9.1 Introduction to 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 for the TPID (Tag Protocol Identifier, residing within the type/
length field of the Ethernet frame) and two bytes for the TCI (Tag Control
Information, starting 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 used to identify
priority frames and the value 4095 (FFF) is reserved, so the maximum possible
number of VLAN configurations is 4,094.
9.1.1 Forwarding Tagged and Untagged Frames
Each port on the Switch is capable of passing tagged or untagged frames. To
forward a frame from an 802.1Q VLAN-aware switch to an 802.1Q VLAN-unaware
TPID
2 Bytes
User Priority
3 Bits
CFI
1 Bit
VLAN ID
12 bits
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Страница 8: ...Safety Warnings XGS 4728F User s Guide 8 ...
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Страница 30: ...Chapter 1 Getting to Know Your Switch XGS 4728F User s Guide 30 ...
Страница 34: ...Chapter 2 Hardware Installation and Connection XGS 4728F User s Guide 34 ...
Страница 42: ...Chapter 3 Hardware Overview XGS 4728F User s Guide 42 ...
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Страница 78: ...Chapter 7 System Status and Port Statistics XGS 4728F User s Guide 78 ...
Страница 92: ...Chapter 8 Basic Setting XGS 4728F User s Guide 92 ...
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Страница 114: ...Chapter 9 VLAN XGS 4728F User s Guide 114 ...
Страница 118: ...Chapter 10 Static MAC Forward Setup XGS 4728F User s Guide 118 ...
Страница 148: ...Chapter 14 Bandwidth Control XGS 4728F User s Guide 148 ...
Страница 162: ...Chapter 17 Link Aggregation XGS 4728F User s Guide 162 ...
Страница 186: ...Chapter 21 Policy Rule XGS 4728F User s Guide 186 ...
Страница 230: ...Chapter 25 AAA XGS 4728F User s Guide 230 ...
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Страница 332: ...Chapter 38 Maintenance XGS 4728F User s Guide 332 ...
Страница 358: ...Chapter 41 Syslog XGS 4728F User s Guide 358 ...
Страница 366: ...Chapter 42 Cluster Management XGS 4728F User s Guide 366 ...
Страница 370: ...Chapter 43 MAC Table XGS 4728F User s Guide 370 ...
Страница 374: ...Chapter 44 IP Table XGS 4728F User s Guide 374 ...
Страница 378: ...Chapter 46 Routing Table XGS 4728F User s Guide 378 ...
Страница 381: ...381 PART VI Troubleshooting Product Specifications Troubleshooting 383 Product Specifications 393 ...
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Страница 402: ...Chapter 49 Product Specifications XGS 4728F User s Guide 402 ...
Страница 403: ...403 PART VII Appendices and Index IP Addresses and Subnetting 409 Legal Information 405 Index 417 ...
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Страница 408: ...Appendix A Legal Information XGS 4728F User s Guide 408 ...