Huawei Quidway S7700 Configuration Manual - Ethernet page 82

Quidway S7700 Smart Routing Switch
Configuration Guide - Ethernet
Figure 3-1 Schematic diagram for a typical VLAN application
VLAN-A
This application shows the following VLAN advantages:
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Basic VLAN Concepts and Principles
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Issue 01 (2011-07-15)
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VLAN-B
VLAN-C
Broadcast domains are confined. A broadcast domain is confined to a VLAN. This saves
bandwidth and improves network processing capabilities.
Network security is enhanced. Packets from different VLANs are separately transmitted.
PCs in one VLAN cannot directly communicate with PCs in another VLAN.
Network robustness is improved. A fault in a VLAN does not affect PCs in other VLANs.
Virtual groups are set up flexibly. With the VLAN technology, PCs in different
geographical areas can be grouped together. This facilitates network construction and
maintenance.
802.1Q and VLAN frame format
A conventional Ethernet frame is encapsulated with the Length/Type field for an upper-
layer protocol following the Destination address and Source address fields, as shown in
Figure 3-2.
Figure 3-2 Conventional Ethernet frame format
6bytes 6bytes
Source
Destination
address
address
IEEE 802.1Q is an Ethernet networking standard for a specified Ethernet frame format. It
adds a 32-bit field between the Source address and the Length/Type fields of the original
frame, as shown in Figure
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Router
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2bytes 46-1500bytes 4bytes
Data
Length/Type
3-3.
3 VLAN Configuration
Switch3
FCS
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