TP-Link TL-SG108E TL-SG108E V1 User Guide Easy Smart Configuration Utility 191 - Page 29

VLAN, VLAN Implementation

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Easy Smart Configuration Utility User Guide Chapter 6 VLAN The traditional Ethernet is a data network communication technology based on CSMA/CD (Carrier Sense Multiple Access/Collision Detect) via shared communication medium. Through the traditional Ethernet, the overfull hosts in LAN will result in serious collision, flooding broadcasts, poor performance or even breakdown of the Internet. Though connecting the LANs through switches can avoid the serious collision, the flooding broadcasts cannot be prevented, which will occupy plenty of bandwidth resources, causing potential serious security problems. A Virtual Local Area Network (VLAN) is a network topology configured according to a logical scheme rather than the physical layout. The VLAN technology is developed for switches to control broadcast in LANs. By creating VLANs in a physical LAN, you can divide the LAN into multiple logical LANs, each of which has a broadcast domain of its own. Hosts in the same VLAN communicate with one another as if they are in a LAN. However, hosts in different VLANs cannot communicate with one another directly. Therefore, broadcast packets are limited in a VLAN. Hosts in the same VLAN communicate with one another via Ethernet whereas hosts in different VLANs communicate with one another through the Internet devices such as router, the Lay3 switch, etc. The following figure illustrates a VLAN implementation. Figure 6-1 VLAN Implementation Compared with the traditional Ethernet, VLAN enjoys the following advantages. (1) Broadcasts are confined to VLANs. This decreases bandwidth utilization and improves network performance. (2) Network security is improved. VLANs cannot communicate with one another directly. That is, a host in a VLAN cannot access resources in another VLAN directly, unless routers or Layer 3 switches are used. 26

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Easy Smart Configuration Utility
User Guide
Chapter 6
VLAN
The traditional Ethernet is a data network communication technology based on CSMA/CD (Carrier
Sense Multiple Access/Collision Detect) via shared communication medium. Through the
traditional Ethernet, the overfull hosts in LAN will result in serious collision, flooding broadcasts,
poor performance or even breakdown of the Internet. Though connecting the LANs through
switches can avoid the serious collision, the flooding broadcasts cannot be prevented, which will
occupy plenty of bandwidth resources, causing potential serious security problems.
A Virtual Local Area Network (VLAN) is a network topology configured according to a logical
scheme rather than the physical layout. The VLAN technology is developed for switches to control
broadcast in LANs. By creating VLANs in a physical LAN, you can divide the LAN into multiple
logical LANs, each of which has a broadcast domain of its own. Hosts in the same VLAN
communicate with one another as if they are in a LAN. However, hosts in different VLANs cannot
communicate with one another directly. Therefore, broadcast packets are limited in a VLAN.
Hosts in the same VLAN communicate with one another via Ethernet whereas hosts in different
VLANs communicate with one another through the Internet devices such as router, the Lay3
switch, etc. The following figure illustrates a VLAN implementation.
Figure 6-1 VLAN Implementation
Compared with the traditional Ethernet, VLAN enjoys the following advantages.
1
Broadcasts are confined to VLANs. This decreases bandwidth utilization and improves
network performance.
2
Network security is improved. VLANs cannot communicate with one another directly. That
is, a host in a VLAN cannot access resources in another VLAN directly, unless routers or
Layer 3 switches are used.
26